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Chemical Calculations (Stoichiometry)

Updated on February 21, 2015
Stoichiometry is the process of  calculating the relative quantities of reactants and products in chemical reactions.
Stoichiometry is the process of calculating the relative quantities of reactants and products in chemical reactions.

Objectives

Upon completion of this lesson, the students should be able to:

  1. describe a mole
  2. determine molar and molecular masses
  3. calculate the percentage composition of a compound
  4. calculate the empirical and molecular formulas

Introduction

The branch of chemistry, which deals with the numerical relationships of elements and compounds and the mathematical proportions of reactants and products in chemical transformations, is known as stoichiometry. An understanding of the mole concept together with some skills in writing and balancing chemical equations enable us to solve stoichiometric problems involving mass relations of reactants and products in chemical reactions.

Stoichiometry deals with the numerical relationships of elements and compounds and the mathematical proportions of reactants and products in chemical transformations.
Stoichiometry deals with the numerical relationships of elements and compounds and the mathematical proportions of reactants and products in chemical transformations.

The Mole Concept

In chemical calculations it is necessary to consider quantities of substances in terms of the number of atoms, ions or molecules present. The unit devised by chemists in expressing these numbers of atoms, ions, or molecules is called the mole.

Mole is the unit of measurement used in chemistry in expressing amounts of a chemical substance. It has a value of 6.02214129(27)×1023elementary entities of the substance. Chemists use mole to express the amounts of reactants or of products in chemical reactions instead of units of mass or volume.

A mole is defined as that quantity of a substance that contains the same number of ultimate particles (atom, ions, or units of ions) as present in 12g of Carbon -12.

Mole is the unit of measurement used in chemistry in expressing amounts of a chemical substance.
Mole is the unit of measurement used in chemistry in expressing amounts of a chemical substance.

What is molar mass?

The molar mass is the sum of the masses of the atoms present in one mole of a substance, which can be an element or a compound. It can be expressed as a unit of mass per mole like grams/mol, kg/mol.

Examples:
1. Find the molar mass of: Al, H2O, Ca(OH)2
a. Al = 27 g/mol

b. H2O = 18 g/mol

H = 2 at x 1g/mol  =   2g
O = 1 at x 16g/mol =  16g 
                      18g/mol

c. Ca(OH)2­ = 74 g/mol

Ca = 1 at x 40g/mol = 40g
O =  2 at x 16g/mol = 32g
H =  2 at x 1g/mol  =  2g 
                      74g/mol

2. How many moles are present in: 5.4 g of Al, 180 g of H2O?

a. 5.4 g x 1 mol/27g = 0.2 mol
b. 180 g x 1 mol/18g = 10 mol

3. What is the mass of: 5 mol of Ca(OH)2 and 2 mol of Al ?

5 mol of Ca(OH)2

Ca = 1 x 40 = 40
 O = 2 x 16 = 32
 H = 1 x 2 =   2 
             74g

5 mol x 74g/mol = 370g

2 mol of Al

2 mol x 27g/mol = 54 g

Examples on how to calculate molar mass...
Examples on how to calculate molar mass...
 Lorenzo Romano Amedeo Carlo Avogadro di Quaregna e di Cerreto  was an Italian scientist noted for his contributions to molecular theory  and the Avogadro's law.
Lorenzo Romano Amedeo Carlo Avogadro di Quaregna e di Cerreto was an Italian scientist noted for his contributions to molecular theory and the Avogadro's law.
Known as the Avogadro constant,  which is one of the seven SI base units. It is the number of elementary entities (atoms, molecules, ions or other particles) in 1 mole of a substance.
Known as the Avogadro constant, which is one of the seven SI base units. It is the number of elementary entities (atoms, molecules, ions or other particles) in 1 mole of a substance.

Avogadro's Number

The number of molecules in a mole of any molecular substance is the same as the number of atoms in a gram-atom of any number. This number of atom is called the Avogadro’s number, the accepted value of which is 6.02214129(27)×1023 atoms/gram-atom of any element. In other words, a mole is the amount of substance that contains as Avogadro’s number of particles equal to 6.02214129(27) ×1023 or simply expressed as 6.02 x 1023. The particles can be atoms, molecules, or ions.

Examples:

There are 6.02 x 1023 atoms in 1 mol of carbon

There are 6.02 x 1023 molecules in 1 mol of H2­O

There are 6.02 x 1023 Na

6.02 x 1023 Cl in 1 mol of NaCl

The Mole and Avogadro's Number

Mole

Unit system
International System of Unit (SI base unit)
Unit of
Amount of substance
Symbol
mol

Examples:

1. How many atoms are present in:

a. 5 mol of copper

5 mol x 6.02 x 1023 atoms/mol = 30.10 or 3.01x 1023 atoms

b. 48 g of carbon

48 g x 1 mol/12g x 6.02 x 1023 atoms/mol = 24.08 x 1023 or 2.408 x 1023 atoms

2. How many g of H2O will contain 3.01 x 1024 molecules?

3.01 x 1024 molecules x 1 mol/6.02 x 1023 molecules x 18 g/mol = 90g

Percentage Composition

Percentage composition is a statement indicating the percentage of each element present in a compound. In chemistry, this composition is always on a weight basis unless specifically stated otherwise. Sometimes the composition of the mixture of gases is given on a volumetric basis. The computation of the percentage composition from the formula of the compound is based upon the meaning of the symbols and formulas. Each symbol stands for one atomic weight’s worth of the element it represents, and each formula stands for one molecular weight’s worth of the compound it represents.

1. What is the percentage composition of water?

  % H  =  2g/18g  x  100%  =   11.11%
  % O  = 18g/18g  x  100%  =   88.89%
                              100.00%   


2. What is the percentage composition of H2SO4?

  % H  =  2g/98.1g   x  100%  =   2.0%
  % S  =  32g/98.1g  x  100%  =  32.7%
  % O  =  64g/98.1g  x  100%  =  65.3%
                                100.0% 

Empirical Formula

Empirical Formula is a chemical formula denoting the constituent elements of a substance and relative number of atoms of each. It gives the simplest ratio of the number of the atoms.

Example:

What is the empirical compound formula of a compound which contains 2.05% H, 32.65% S, and 65.30% O?

Basis: 100 g of the compound

H = 2.05/100 x 100 g = 2.05 g X 1 at/1g = 2.05 at

S = 32.55/100 x 100 g = 32.65 g x 1 at/32g = 1.02 at

O = 65.30/100 x 100 g = 65.30 g x 1 at/16g = 4.08 at

The formula is not H2.05 S1.02 O4.08. Subscripts are small whole numbers, but they are not rounded off but are divided by the smallest number. The correct formula is H2SO4

H2.05 ­ S1.02 O4.08 = H2SO4

Molecular Formula

Molecular formula is a chemical formula denoting the constituent elements of a substance and the number of atoms of each composing one molecule. It gives the actual ratio of the number of the atoms in a mole of the compound.

Example:

A compound is 85.69% C and 14.31% H. If the molar mass is 56 g/mol. What is the molecular formula of the compound?

Basis: 100 g of the compound

Determine the empirical formula:

C = 85.69 g x 1 at/12 g = 7.14 at

H = 14.31 g x 1 at/1 g = 14.31 at

Empirical Formula = C7.14 H14.31/7.14 = CH2

How to Calculate Percent Composition, Empirical Formulas and Molecular Formulas - Chemistry

Self-Progress Test:

Part I

Solve the following:

  1. What is the mass in grams of:
    1. 2 moles of AlCl3
    2. 8 moles of CaCO3
    3. 5 moles of (NH4)2SO4
    4. 4 moles of C6H12O6
    5. 3 moles of KNO3

Part II

  1. Calculate the number of moles in each of the following:
    1. 68.4 g of sucrose C12H22H11
    2. 80 g of NaOH
    3. 3.01 x 1023 atoms of Al
    4. 6.02 x 1024 molecules of CO2
    5. 12 g of O2

Part III

  1. Find the percentage composition of the following:
    1. Sugar C12H22O11
    2. hydrated copper sulfate CuSO4 5HO
    3. sulfuric acid H2SO4
    4. hematite Fe2O3

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    • profile image

      Teddy Gullem 2 months ago

      Stoichiometry involves using relations between reactants and/or products in a chemical reaction to determine desired quantitative data. Stoichiometry is part of chemistry that studies amounts of substances that are involved in reactions.

    • Camille San Mateo profile image

      Camille San Mateo 2 months ago

      SAN MATEO, CAMILLE C.

      BSN-1

      The study of quatitative aspects of chemical reactions that deals with the numerous relation. It is important because it is the heart of the production of many things that can be use in our everyday lives. Those things are chemically produced through chemical reactions.

    • Bianca Bernardo profile image

      Bianca Bernardo 2 months ago

      Stoichiometry is the quantitative qualities of a chemical reaction. It is used in getting the amount of molecules in a compound or an element, the total masses in a reaction, and even the percentage that each element plays in a reaction. It is essential for us to know the basics in stoichiometry as we should know how much of a reactant will affect a reaction and how much we should only use. This also goes for giving medicines to patients as all chemicals have different reactions to different bodies and knowing how to solve for the percentage or amount of atoms in a reaction will give us a guideline on how much medicine a patient is only supposed to take.

    • profile image

      Christian Paul V. Ogorida BSCE 2 months ago

      Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equals the total mass of the products leading to the insight that the relations among quantities of reactants and products typically form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of product can be empirically determined, then the amount of the other reactants can also be calculated.

    • profile image

      RUSSELL BERNARDINO 2 months ago

      Knowing stoichiometry can help us find out the composition of molecules and general proportions of how to combine things to get them to react completely.

      Stoichiometry is exactly that. It is the quantitative relation between the number of moles (and therefore mass) of various products and reactants in a chemical reaction.

      Having the right proportions of things gets pretty important when you don't have a whole lot of reactants to waste (cost reduction), or when you're in the field of pharmacy (preventing overdose and death).

      Additionally, the skills you get from learning how to do stoichiometry problems are probably THE most important thing to take away from a chemistry class. Dimensional analysis (aka. unit cancellation) will help you in every single science class you ever take - especially physics - and can often help you get a correct answer on a problem you don't completely understand as long as you know your answers has the correct units.

    • Gil Calderon profile image

      Gil Calderon 2 months ago

      What stoichiometry is, it allows us to do is to start comparing the quantities of reactants and product together. So that when we have certain amount of reactant we can figure out how product we can produced, or if we know how much product is produced we can turn how much reactant must have been used up in order to produced that product. However, what we relies on is to understand not only the numbers in a balance equation but also the masses of those component. What can we do is to count out and take quantity of a large number them so that we can mass say an electronic balance a large number of these molecules or compound in an atom.

    • davejshv profile image

      Dave Joshua Villangca 2 months ago

      VILLANGCA, DAVE JOSHUA B.

      BSN-I

      Stoichiometry also means chemical computations. Studying this chapter is quite difficult but knowing the mole concepts, how to balance an equation and understanding the molecular mass of elements and compounds makes it easier for us to solve stoichiometric problems. When it comes to relevance of this topic to my course, which is nursing, is that we can understand more the compositions, numbers of molecules and percentage composition of the medications that we will be giving to our future clients. Because of that, we will be able to prevent errors that may cause the patient to suffer more or worst, death.

    • profile image

      TORIBIO, PAULINE LOUISE A. 2 months ago

      TORIBIO, PAULINE LOUISE A.

      BSN-I

      Stoichiometry is the process of calculating the number of reactants and products of a reaction. This chapter of chemistry may be hard but useful for a nursing student like me. As of what I have read, I can relate this to medical dispensing. For example, some medications are given based on weight and age. We have to re-calculate the weight or age with the medicine that a patient will take. A wrong calculation may lead to overdose. That is why this chapter is important for us.

    • profile image

      Denise arceo 8 months ago

      Denise R. Arceo

      BAC- II

      Stoichiometry deals with the computation in chemistry- it talks about chemical computations based on molar masses and ratios. Balancing out the chemicals and reactants using equations and computations.

      In communication, we can use the value of balancing our time to be productive and release our creative juices in our respective fields and to balance our time efficiently.

    • profile image

      Aldrinsntg 8 months ago

      Aldrin L Santiago BSPSY II

      stoichiometry deals with chemical calculations, it's hard to understand it but as we go along in the lesson we can understand how to calculate the molar mass molecular mass and the percentage calculations of an element. It talks about the quantitative measurement. I can use these calculations in my future field.

    • profile image

      Aldrin L Santiago 8 months ago

      Aldrin L Santiago BSPSY II

      stoichiometry is hard to understand, but as we get along the lesson proper, we can say that it is important in our daily lives. It talks about the chemical calculations- how to compute the molar mass, molecular mass, and the percentage composition of an element. I can use this in my future field for me to handle different patients. How to hold my temper and calm myself.

    • profile image

      jerson maniego BSHM-4 8 months ago

      Stoichiometry

      Stoichiometry is simply the math behind chemistry. Given enough information, one can use stoichiometry to calculate masses, moles, and percents within a chemical equation.

    • profile image

      Luisito Dimagiba 8 months ago

      BSHM

      Is an expression which states the number and type of atoms present in a molecule of a substance. The type of atom is given using element symbols. The number of atoms is indicated by a subscript following the element symbol.

    • Rafael Adriano profile image

      Rafael Adriano 9 months ago

      Stoichiometry measures these quantitative relationships, and is used to determine the amount of products/reactants that are produced/needed in a given reaction. Describing the quantitative relationships among substances as they participate in chemical reactions is known as reaction stoichiometry. As an ABCOM student we need to be accurate for everything from simplex up to the most complex and doing it with proper information dissemination.

    • Jahna Carmella profile image

      Jahna Carmella 9 months ago

      Jahna Carmella B. Galvez

      BEED-II (Inorganic Chemistry/ TF/ 12:30-2:00)

      Stoichiometry is important in production of a lot of things like what we see in our daily life. Soap, medicines, chemicals, gasoline, and also chocolate bars are just a few examples we use that are produced through chemical reactions.

    • profile image

      Mary Grace Gonzales 9 months ago

      BU BSTM 4 Sci 202 T-F 7:30-12:00

      In a chemical reaction, matter can neither be created nor destroyed, so the products that come out of a reaction must equal the reactants that go into a reaction. Stoichiometry is the measure of the elements within a reaction.[1] It involves calculations that take into account the masses of reactants and products in a given chemical reaction. Stoichiometry is one half math, one half chemistry, and revolves around the one simple principle above - the principle that matter is never lost or gained during a reaction. The first step in solving any chemistry problem is to balance the equation.

    • mariseperez08 profile image

      mariseperez08 9 months ago

      Perez, Nina Marise V.

      BEED- II (TF/ 12:30-2:00/ CAS 105)

      Stoichiometry means "element measurement" in Greek and is also known as Mass Relations. The principles of stoichiometry are based on the Law of Conversation of Mass, the Law of Multiple Proportions, and the Law of Constant Composition. In order to satisfy all three laws, every chemical reaction and corresponding equation needs to have a set molar ratio for its reactants and products that explains how it proceeds to completion every time. Once determined, the molar ratio for an equation does not change as long as the equation itself is untouched and no other chemicals are added to the reaction.

      Because the calculations in stoichiometry are based on molar ratios, the molar masses of the products can be used to determine theoretical yields and limiting reagents. Stoichiometry can also help determine the concentrations of solutions that were used, provided that enough variables are accounted for. A proper stoichiometric molar ratio functions forwards and backwards so that calculating values for the reactants can be performed if the corresponding values for the products are known.

      Stoichiometry is important because it explains the relationships of reactants and products in chemical reactions. Without stoichiometry, it would be impossible to determine how much of a certain chemical is needed to yield a result or what molar amounts of each reactant and product are present in a completed reaction.

      Stoichiometry is important because it explains the relationships of reactants and products in chemical reactions. Without stoichiometry, it would be impossible to determine how much of a certain chemical is needed to yield a result or what molar amounts of each reactant and product are present in a completed reaction.

    • profile image

      frances birco 9 months ago

      Frances Birco

      BAC-II

      Stoichiometry is the process of calculating the relative quantities of reactants and products in chemical reactions. In being a field reporter in the future, we should verify and simplify the information for the audience to easily understand the news and not having so much time reporting a news to avoid confussion and misunderstanding.

    • Elize Bantang 14 profile image

      Elize Bantang 14 9 months ago

      Eliza B. Merle BEEd-ll

      Stoichiometry is the section of chemistry that involves using relationships between reactants and products in a chemical reaction to determine desired quantitative data. In Greek, stoikhein means element and metron means measure, so Stoichiometry literally translated means the measure of elements. In chemical calculations it is necessary to consider quantities of substances in terms of the number of atoms, ions or molecules present. The unit devised by chemists in expressing these numbers of atoms, ions or molecules is called the mole. Mole is the unit of measurement used in chemistry in expressing amounts of a chemical substance. The molar mass is the sum of the masses of the atoms present in one mole of a substance, which can be an element or a compound. It can be expressed as a unit of mass per mole like grams/mol. Kg/mol. Empirical formula is a chemical formula denoting the constituent elements of a substance and relative number of atoms of each. It gives the simplest ratio of the number of the atoms. Stoichiometry is very useful in my course because in the future I am the assessor of my student's learning by computing their grades and also measuring their attitudes and characters inside the classroom.

    • JosephineLopez04 profile image

      JosephineLopez04 9 months ago

      Lopez, Josephine V.

      BEEd-II (BSC206B) (TF/ 12:30-2:00/ CS 105)

      The term stoichiometry was first used by Jeremias Benjamin Richter in 1792 when the first volume of Richter's Stoichiometry or the Art of Measuring the Chemical Elements was published. Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equals the total mass of the products leading to the insight that the relations among quantities of reactants and products typically form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of product can be empirically determined, then the amount of the other reactants can also be calculated.

    • profile image

      Amira Ismail 9 months ago

      Amira Ismail

      GENERAL CHEMISTRY

      BAC-II

      he word stoichiometry derives from two Greek words: stoicheion (meaning "element") and metron (meaning "measure"). Stoichiometry deals with calculations about the masses (sometimes volumes) of reactants and products involved in a chemical reaction. It is a very mathematical part of chemistry, so be prepared for lots of calculator use.

    • Maryn Pineda profile image

      Maryn Pineda 9 months ago

      MARY NOELLE PINEDA BAC-II GENERAL CHEMISTRY TF 7:30-12:00 We have learned from reading the slides about the balancing equations and enabling us to solve stoichiometric problems involving mass relations of reactants and products of chemical reactions. We have learned about the mole concept, molar mass, about the Avogadro's number, the percentage composition, the empirical formulas and molecular formulas for of course, solve numerical problems. This part of the lesson is necessary to an AB Communication student for information dissemination, determining molar and molecular masses, calculate percentage composition of a compound, the empirical and molecular formulas.

    • Nik Miranda profile image

      Nik Miranda 9 months ago

      Miranda, Nixieline

      BAC II

      Using a balanced chemical equation to calculate amounts of reactants and products is called stoichiometry. It is a super technical-sounding word that simply means using ratios from the balanced equation. In this article, we will discuss how to use mole ratios to calculate the amount of reactants needed for a reaction.

    • profile image

      Jannilene Tubon BAC II 9 months ago

      Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equals the total mass of the products leading to the insight that the relations among quantities of reactants and products typically form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of product can be empirically determined, then the amount of the other reactants can also be calculated.

    • AZ08 profile image

      AZ08 9 months ago

      Eimeren Grace DC. Soriaga (Bs-PsyII)

      For me Stoichiometry is important because it allows us to predict how much of reactant is consumed in a chemical reaction, or how much unwanted product is generated. This is especially important in medicine, because we would want the amount of toxic side products formed from the biochemical processes acting on the consumed medicine in our body to be minimal.

    • Maria Luz Mendoza profile image

      Maria Luz Mendoza 9 months ago

      Ma. Luz C. Mendoza BEED II

      Stoichiometry means "element measurement" in Greek and is also known as Mass Relations. The principles of stoichiometry are based on the Law of Conversation of Mass, the Law of Multiple Proportions, and the Law of Constant Composition. In order to satisfy all three laws, every chemical reaction and corresponding equation needs to have a set molar ratio for its reactants and products that explains how it proceeds to completion every time. Once determined, the molar ratio for an equation does not change as long as the equation itself is untouched and no other chemicals are added to the reaction. Because the calculations in stoichiometry are based on molar ratios, the molar masses of the products can be used to determine theoretical yields and limiting reagents. Stoichiometry can also help determine the concentrations of solutions that were used, provided that enough variables are accounted for. A proper stoichiometric molar ratio functions forwards and backwards so that calculating values for the reactants can be performed if the corresponding values for the products are known.

    • Zipagan profile image

      Zipagan 9 months ago

      Dhaina Marie B. Zipagan (BAC-II)

      Stoichiometry involves quantitative relationships in achemical reaction. Stoichiometric factors also called mole ratios, are based on the coefficients in the balanced equation and are used to relate moles of one reactant or product to another. The subject of stoichiometry involves quantitative calculations based on chemical formulas and chemical equation: Molecular masses and formula masses are the masses, expressed in atomic mass units (u), of individual molecules and formula units. They are calculated from the masses of the atoms represented in the molecular or empirical formulas, respectively. Molecular mass applies only to molecular compounds; formula mass is appropriate for ionic compounds; The Mole and Avogadro’s Number-A mole (mol) is an amount of substance containing a number of elementary entities (atoms, molecules, formula units, etc.) equal to the number of atoms in exactly 12 g of carbon-12; The Mole and Molar Mass-The mass, in grams, of one mole of substance is called the molar mass; it is numerically equal to an atomic, molecular, or formula mass but carries the unit g/mol. Conversions between the number of moles and the number of grams of a substance require molar mass as a conversion factor. Calculations involving volume, density, and numbers of atoms or molecules can also be used to determine molar quantities.

      Apart from the regular and necessary use of stoichiometry in just about every single industrial application which uses chemical reactions in the world.... here are a couple everyday household examples;-

      Say you have a cookie recipe that makes a dozen cookies. The "chemical" equation for this might look something like this;-4 cups flour + 2 eggs + 200g butter + 1 cup sugar = 12 cookies.

      But you only have 1 egg. So, how much of each of the other ingredients do you need and how many cookies will the new recipe make?Well, if you divided each of the ingredients by two, the new equation would be;2 cups flour + 1 eggs + 100g butter + 1/2 cup sugar = 6 cookies.

    • profile image

      Patricia Ann T. Cruz BSTM lll 9 months ago

      Stoiciometry involves quantitative relationship in a chemical reaction. Stoiciometry also called mole rations are based on the coefficients in the balance equation and are use to relate moles of one reactant or product to another. And almost all stoiciometry problems can be solved in just four simple steps balance the equation, convert units of a given substance moles, using the mole ratio, calculate the moles substance yielded by the reaction

    • profile image

      Karen Mañalac. BAC IV 9 months ago

      Stoichiometry measures these quantitative relationships, and is used to determine the amount of products/reactants that are produced/needed in a given reaction. Describing the quantitative relationships among substances as they participate in chemical reactions is known as reaction stoichiometry.

      Stoichiometry is important because it explains the relationships of reactants and products in chemical reactions. Without stoichiometry, it would be impossible to determine how much of a certain chemical is needed to yield a result or what molar amounts of each reactant and product are present in a completed reaction.

    • Cristina Perez profile image

      Cristina Perez 9 months ago

      Perez, Ma. Cristina M.

      BEEd-II (BSC206B) (TF/ 12:30-2:00/ CS 105)

      Stoichiometry is at the heart of the production of many things you use in your daily life. Soap, tires, fertilizer, gasoline, deodorant, and chocolate bars are just a few commodities you use that are chemically engineered, or produced through chemical reactions. Chemically engineered commodities all rely on stoichiometry for their production.

      But what is stoichiometry? Stoichiometry is the calculation of quantities in chemical equations. Given a chemical reaction, stoichiometry tells us what quantity of each reactant we need in order to get enough of our desired product. Because of its real-life applications in chemical engineering as well as research, stoichiometry is one of the most important and fundamental topics in chemistry.

    • Maniella de Leon profile image

      Maniella de Leon 9 months ago

      De Leon, Maniella Assumpta M.

      BEEd-II (BSC206B) (TF/ 12:30-2:00/ CS 105)

      In chemistry it is very important to understand the relationship between reactants and products in a reaction. Stoichiometry is exactly that. It is the quantitative relation between the number of moles (and therefore mass) of various products and reactants in a chemical reaction. Reaction stoichiometry allows us to determine the amount of substance that is consumed or produced by a reaction. The following video considers the first part of this: how much of a reactant is consumed in a chemical reaction. Product formation is discussed elsewhere. Knowing stoichiometry can help you find out the composition of molecules and general proportions of how to combine things to get them to react completely.

    • Carmela Perez profile image

      Carmela Perez 9 months ago

      Perez, Ma. Carmela M.

      BEED- II (TF/ 12:30-2:00/ CAS 105)

      Stoichiometry is the accounting, or math, behind chemistry. Given enough information, one can use stoichiometry to calculate masses, moles, and percents within a chemical equation. Stoichiometry is a section of chemistry that involves using relationships between reactants and/or products in a chemical reaction to determine desired quantitative data. In Greek, stoikhein means element and metron means measure, so stoichiometry literally translated means the measure of elements. In order to use stoichiometry to run calculations about chemical reactions, it is important to first understand the relationships that exist between products and reactants and why they exist, which require understanding how to balanced reactions. As a future teacher, stoichiometry is somewhat relevant to our course because it deals with numerical figures and computations wherein in assessing the learners we need to know how to compute properly their grades and make it reasonable, balanced, and precisely.

    • Jucel Salvador profile image

      Jucel Salvador 9 months ago

      Salvador, Jucel Roma M.

      BEEd-II (TF/12:30-2:00/CS 105)

      The branch of chemistry which deals with the numerical relationships of elements and compounds and the mathematical proportions of reactants and products in chemical transformations is known as stoichiometry. This allows us to make predictions about the outcomes of chemical reactions. We can predict the mass of a product or the volume of a gas. Without the help of stoichiometry, it would be difficult for the students to determine how much chemicals or molar ammounts are needed to complete a reaction because the calculations in stoichiometry are based on molar ratios. As a student, stoichiometry is quite difficult to learn yet challenging. This gives us the ability to learn different chemicals and formulas to calculate.

    • Nikki Villaroman profile image

      Nikki Villaroman 9 months ago

      Villaroman Nikki D.C. Beed III

      T/F BSC206b cas 105 12:30-2:00

      Stoichiometry measures these quantitative relationships, and is used to determine the amount of products/reactants that are produced/needed in a given reaction. Describing the quantitative relationships among substances as they participate in chemical reactions. As a future educator i should be able to give learners grade measured to their performance and be able to explain of how they were able to acquire that certain grade.

    • Maricar Ramos profile image

      Maricar Ramos 10 months ago

      Maricar Ramos BspsyII

      Stoichiometry in chemistry, the study of the quantitative relationships between the weights (volumes) of reacting substances. Stoichiometry includes the derivation of chemical formulas and chemical equations, and its principles are used in the calculations of chemical analysis. The major postulates of stoichiometry are derived from Avo- gadro’s law, Gay-Lussac’s law of combining volumes, the law of multiple proportions, the law of definite proportions, the principle of the conservation of mass, and the law of equivalent proportions. The rules of stoichiometry govern all calculations related to chemical equations. Stoichiometric calculations are widely used in chemical engineering and metallurgy.

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      ChristianAnthonyRValino BSPsy II (7:30-12:00 T\F) 10 months ago

      Stoichiometry is at the heart of the production of many things we use in our daily life. Soap, tires, fertilizer, gasoline, deodorant, and chocolate bars are just a few commodities you use that are chemically engineered, or produced through chemical reactions. Chemically engineered commodities all rely on stoichiometry for their production. It is know as a branch of chemistry, which deals with the numerical relationships of elements and compounds and the mathematical proportions of reactants and products in chemical transformations.

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      Chella P. Maniquiz BSTM TF-7:30-12:00 10 months ago

      Stoichiometry is important because it explains the relationships of reactants and products in chemical reactions. Without stoichiometry, it would be impossible to determine how much of a certain chemical is needed to yield a result or what molar amounts of each reactant and product are present in a completed reaction.

      It is relevant in our course, especially in baking because we have to be certain in the amount of ingridients that we are going to mix.

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      Jerson G Maniego BSHM-4 (7:30-12:00 T\F) 10 months ago

      Stoichiometry is the study of the quantitative relationships or ratios between two or more substances undergoing a physical change or chemical change (chemical reaction). The word derives from the Greek words: stoicheion (meaning "element") and metron (meaning "to measure"). Most often, stoichiometry calculations deal with the mass or volumes of products and reactants.

    • Vivianjane Mempin profile image

      Vivianjane Mempin 10 months ago

      Vivian Jane M. Mempin

      BAC-II

      Gen.Chemistry

      TF/7:30-12:00/CS301

      Stoichiometry deals with the calculation of the relative quantities of reactants and products in chemical transformations. This is necessary when it comes to laboratory experiments to produce a desired chemical reaction. Why or How? Because knowing how to balance equations, knowing the appropiate proportion or percentage of elements and compounds in a given substance, knowing the simple and exact ratio of number of atoms in a mole of a given compound, will lead you the desired result of your experiment. Failure to do so may result to lab accidents and wrong solutions.

      In Communication, we have to balance out every information we receive from various sources. We have to know what percentage of it are true and what portion of it are lies. We also have to make sure that every composition of our news report is equally proportioned so that we could give our audience or listeners a good and accurate news report. Having done it may guarantee high ratings for our network.

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      Shara Mae T. Rivera BSHM 4-1 SCI 202 (TF 7:30-12:00) 10 months ago

      In chemistry, it is often important to know how efficient a reaction is. This is because when a reaction is carried out, the reactants may not always be present in the proportions written in the balanced equation. As a result, some of the reactants will be used, and some will be left over when the reaction is completed.

    • PatrickTan33BUHM profile image

      PatrickTan33BUHM 2 years ago

      Patricktan33BUHM

      stoichiometry is Help in our field HM, because it can help us to know the kinds of chemicals that we will be using in cleaning. We can know of the chemicals that we are using are safe especially to our customer. As an HM student, stoichiometry really helps us a lot in our field. This deals with the interaction of chemicals to each other that we are dealing with in the future. this is a token for dealing with our future guests. Telling things to them that is accurate is thwir pleasure. This will be very helpful in pur field, it will let us know the kinds of chemical related in to our course.

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      MonicSarmiento 2 years ago

      31Sarmiento, MDC BUHM

      As we all know, Stoichiometry is all about measuring of elements. In our field, Hospitality Management, Stoichiometry is very much useful especially in Housekeeping Department and Food and Beverage Department. In cleaning. we uses different chemicals wherein we must use an exact amount for its good reaction. In preparing foods, we must also know to use right amount of ingredients specifically those additives that may harm to our costumers. Having knowledge about Stoichiometry really help our job easier and better.

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      MonicSarmiento 2 years ago

      31Sarmiento, MDC BUHM

      As we all know, Stoichiometry is all about measuring of elements. In our field, Hospitality Management, Stoichiometry is very much useful especially in Housekeeping Department and Food and Beverage Department. In cleaning. we uses different chemicals wherein we must use an exact amount for its good reaction. In preparing foods, we must also know to use right amount of ingredients specifically those additives that may harm to our costumers. Having knowledge about Stoichiometry really help our job easier and better.

    • Jole Ymenel Tila profile image

      Jole Ymenel Tila 2 years ago from Pulilan, Bulacan

      Tila Jole Ymenel F. BUHM

      The quantitative relationship among reactants and products is called stoichiometry. Stoichiometry is very important in chemical equations because it tells you the relationship between substances in the same chemical equation. A balanced chemical equation is not just a qualitative description of a reaction, it is also quantitative. It tells us not just what the reactants and products are, but also the relative amounts of reactants and products that are involved in the reaction. The coefficients in the balanced equation tell us the relative number of formula units for each compound that participate in or are produced by the reaction.

    • SarmientoMonic profile image

      Monic dela Cruz Sarmiento 2 years ago from San Miguel, Bulacan

      31Sarmiento, MDC BUHM

      As we all know, Stoichiometry is all about measuring of elements. In our field, Hospitality Management, Stoichiometry is very much useful especially in Housekeeping Department and Food and Beverage Department. In cleaning. we uses different chemicals wherein we must use an exact amount for its good reaction. In preparing foods, we must also know to use right amount of ingredients specifically those additives that may harm to our costumers. Having knowledge about Stoichiometry really help our job easier and better.

    • Paulo Tomas profile image

      Paulo Tomas 2 years ago

      TOMAS JP BUHM

      Stoichiometry is the art of figuring how much stuff you'll make in a chemical reaction from the amount of each reagant you start with especially important in medicine, because we would want the amount of toxic side products formed from the biochemical processes.

    • Castro F C BUTM profile image

      Fatima Cruz Castro 2 years ago

      7 CASTRO F C BUTM 2014

      Stochiomestry is important in our field, and it is a part of chemistry and they having a relationship of moles to atomic weights, this matter is also interesting but we need to give time to understand this and i think we need this in our working career.

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      kennethcorpuz 2 years ago

      30 corpuz kenneth B. TM

      chemical calculation is contribute of calculate molecular and stoichiometry is a learn and about weight and atomic weight and control of experimental and use of laboratory apparatuses.

    • Rad Mesina profile image

      Rad Mesina 2 years ago from Calumpit, Bulacan

      23 MESINA, DJ BUHM

      Stoichiometry is important in us hospitality management students. and it is also important to know how to balance the chemical that you apply in our food.

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      Clarenz Maximo 2 years ago

      21 MAXIMO, CR BUTM

      Stoichiometry is the calculation of quantitative (measurable) relationships of the reactants and products in chemical reaction.

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      Phoebe Sp 2 years ago

      Stoichiometry is a branch of chemistry where we can determine the percentage composition of a compound. Stoichiometry is very essential because it helps us know the molecular and empirical formulas of compounds. It is important because without it, we wouldn't be able to know and determine the moles of a chemical formula.

      SAN PEDRO, PM BUTM 35

    • jairafulgencio profile image

      jairafulgencio 2 years ago

      FULGENCIO JM BUTM 2014

      Stoichiometry is the part of chemistry that studies amounts of substances that are involved in reactions. You might be looking at the amounts of substances before the reaction.

    • Rollyne Munsayac profile image

      Rollyne Munsayac 2 years ago

      23 MUNSAYAC, RE BUTM 2014

      Stoichiometry is the part of chemistry that studies amounts of substances that are involved in reactions. We should know the proper and right amount and mixture of ingredients.

    • yuriannesantos profile image

      yuriannesantos 2 years ago

      35, Santos YA BUTM 2014

      Stoichiometry is the branch of chemistry, which deals with the numerical relationships of elements and compounds and the mathematical proportions of reactants and products in chemical transformations. We need to study stoichiometry because we are dealing with some chemicals and we need to know how to handle the appropriate amount in mixing and making some chemicals in a certain food.

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      28Quizon,CA BUTM 2 years ago

      Stoichiometry which deals with the numerical relationships of elements and compounds and the mathematical proportions of reactants and products in chemical transformations,

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      Zyrine Mae Taruc 2 years ago

      Taruc, Z.D BUTM 2014

      Stoichiometry having a relationship of moles to atomic weights, the ratios that are arrived at by stoichiometry can be used to determine quantities by weight in a reaction described by a balance equation.

    • Jonna Mae Book profile image

      Jonna Mae Book 2 years ago

      BOOK, JM BUTM 2015

      Stoichiometry rests upon the very basic laws that help to understand it better, the law of multiple proportions and the law of reciprocal proportions. In general, chemical reactions combine in definite ratios of chemicals. Since chemical reactions can neither create nor destroy matter, nor transmute one element into another, the amount of each element must be the same throughout the overall reaction. For example, the number of atoms of a given element X on the reactant side must equal the number of atoms of that element on the product side, whether or not all of those atoms are actually involved in a reaction.

    • Elli Rose Gabriel profile image

      Elli Rose Gabriel 2 years ago

      1 BALELA, E.G BUTM 2014

      In my field as a tourism student, knowing stoichiometry can help you find out the composition of molecules and general proportions of how to combine things to get them react completely.

    • Melanie Samson profile image

      Melanie Samson 2 years ago

      SAMSON, MH BUTM2014-2015

      Calculation of Chemicals is very important in my chosen field because Tourism Management as sister of Hospitality Management, we may be involved in restaurants as a cook and by this, this lesson will be a big help for us for the calculation of ingredients and other sources available for cooking.

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      27 PARUNGAO, GT BUTM 2 years ago

      Stoichiometry involves quantitative calculations based on chemical formulas and chemical equations. In this lesson you will learn all about conversion factors and how to use them. You will use them to solve general problems and then, to solve the stoichiometry problems.

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      Marife DG. Montejo 2 years ago

      Stoichiometry is really hard but when you started to understand it and do the correct steps you can solve the problems. Just also like in reality all you need to do is analyze your problems well and do things in the right way to solve it.

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      Mary Rose Banzon 2 years ago

      Stoichiometry is the process of calculating the relative quantities of reactants and products in chemical reactions. This matter was interesting yet it hard to understand but in time as a tourism student i think we really need this in our industry.

    • Capanas MJ BUHM profile image

      Capanas MJ BUHM 2 years ago

      Capanas MJ BUHM

      The chemical bonding in our daily lives is that we have to learn how to be independent.

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      MarjorieLansanganBSHM 2 years ago

      Stoichiometry is a section of chemistry that involves using relationships between reactants and/or products in a chemical reaction to determine desired quantitative data.stoichiometry we can help in Hospitality management to balance the chemical and food or alcohol.

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      Reniel Carillo 2 years ago

      stoichiometry we can help in Hospitality management to balance the chemical and food or alcohol.

    • Adrienne DelaCruz profile image

      Adrienne DelaCruz 2 years ago

      As a bshm student,stoichiometry It helps to balance the amount of chemical or ingredients we can mix food clearly.

    • Julien Villanueva profile image

      Julien Villanueva 2 years ago

      Villanueva, Julien / BUHM 2014-2015

      Stoichiometry is important because it allows us to predict how much of reactant is consumed in a chemical reaction, or how much unwanted product is generated. This is especially important in medicine, because we would want the amount of toxic side products formed from the biochemical processes acting on the consumed medicine in our body to be minimal.

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      john angelo ortega BSHM2 2 years ago

      stoichiometry is very important component of chemistry, especially in our field as a bshm student, it was very useful when I start working as a chef, having a knowledge about this can help me to know the proper amount of ingredients i needed to make a specific food. also in cleaning a hotel being a housekeeper it can help me by knowing the balance amount of chemicals needed to clean a specific part of a hotel

    • Carlo Buencamino profile image

      Jan Carlo Buencamino 2 years ago from Banga 2nd Plaridel Bulacan

      Stoichiometry .

      In Hospitality Management it helps us to know how many / how much of certain ingredients must be added

    • Trisha Vanguardia profile image

      Patrisha Anne D.Vanguardia 2 years ago from San Ildefonso,Bulacan

      Stoichiometry helps us to balance equations.

      as a Hospitality Management student it helps us to calculate the foods or dishes that we can make with our available amount of ingredients in the kitchen.

    • Glenric Samaniego profile image

      Glenric Samaniego 2 years ago

      It is very helpful for our course because it helps us know the amount to be added in a certain beverage or meal.

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      john andrew Cabrera 2 years ago

      Stoichiometry is in relevance on our chosen field because it is the calculation of quantities in chemical equations. it is important in field of Hospitality Management because it can hepl us to balance how many chemicals we can use and we can mix beverage properly by computing it.

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      jessa pantan 2 years ago

      Stoichiometry is important in field of Hospitality Management because it can hepl us to balance how many chemicals we can use and we can mix beverage properly by computing it. There are so many way that Stoichiometry can help us.

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      Eimon Paolo 2 years ago

      Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equals the total mass of the products leading to the insight that the relations among quantities of reactants and products typically form a ratio of positive integers.

    • simplyariannejoy profile image

      simplyariannejoy 2 years ago

      17 Flores, AJ BUHM

      Stoichiometry is a section of chemistry that involves using relationships between reactants and/or products in a chemical reaction to determine desired quantitative data. In relation to our course, we often use chemicals and we should know the difference between the two, reatants and products and what products or reactants that may harm our beloved guest and customers. Stoichiometry is really important because it allows us to predict how much of reactant is consumed in a chemical reaction, or how much unwanted product is generated.

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      Johnmarverickr 2 years ago

      Knowing stoichiometry can help you find out the composition of molecules and general proportions of how to combine things to get them to react completely.Having the right proportions of things gets pretty important when you don't have a whole lot of reactants to waste (cost reduction), or when you're in the field of pharmacy (preventing overdose and death.

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      mikaela igaya 2 years ago

      18 IGAYA MC BUTM

      Stoichiometry is important because it allows us to predict how much of reactant is consumed in a chemical reaction, or how much unwanted product is generated. This is especially important in medicine, because we would want the amount of toxic side products formed from the biochemical processes acting on the consumed medicine in our body to be minimal. So they want to know about this topic because is it very important and need in our life.

    • renzocauzon profile image

      renzocauzon 2 years ago

      09 Cauzon,RA BUHM

      Stoichiometry is important because it allows us to predict how much of reactant is consumed in a chemical reaction. As a HM student it helps us to calculate the foods or dishes that we can make with our available amount of ingredients in the kitchen. It may help us to do our job properly.

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      Miguel Panlilio 2 years ago from Baliuag Bulacan

      Panlilio, Miguel Austin R. BUHM14

      this is very helpful to my course, we should know the proper and right amount and mixture of ingredients whether it is food or chemicals. we should know how to balance them. knowing the right mixture and balance will help me do my job properly and successful.

    • Winnie Aquino profile image

      winnie rose inoncillo aquino 2 years ago from San Rafael, Bulacan

      2 Aquino, WR BUHM 2014

      Stoichiometry is a study that you have to really understand and know the different objectives of it, likewise in one course, Hospitality Management in particular, it is a field that you also have to understand well to be able to perform you have to do without any wrong move and with a serious knowledge involve.

    • simplyariannejoy profile image

      simplyariannejoy 2 years ago

      17 Flores, AJ BUHM

      Stoichiometry is a section of chemistry that involves using relationships between reactants and/or products in a chemical reaction to determine desired quantitative data. In relation to our course, we often use chemicals and we should know the difference between the two, reatants and products and what products or reactants that may harm our beloved guest and customers. Stoichiometry is really important because it allows us to predict how much of reactant is consumed in a chemical reaction, or how much unwanted product is generated. Stoichiometry is a pretty fundamental concept and is often used for such things like balancing equations and determining flow rates of a chemical process.

    • Richmond V profile image

      Richmond V 2 years ago from Bustos, Bulacan

      Stoichiometry is very important in order for us to understand the relationship between reactants and products in a reaction. It can also help us on how to figure out the right proportions of things.

    • paguiligan julia profile image

      Julia Ann 2 years ago

      37 Paguiligan, JAT BUHM

      Stoichiometry is also very important in the field of HM student because it helps us to calculate the recipe of the foods that we cooked and also it's help to manage our time.

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      HoneygraceSalonga 2 years ago

      SALONGA, HG. C BUHM 15

      Chemical Calculation:

      As stated above, stoichiometry deals with the numerical relationships of elements and compounds. Its relevance to our course is that through understanding the mole concept fusioned with the ability to balance chemical equations, we would be able to solve stoichometric problems and thus we could determine the limitations of the amount or dosages of substances that we can combine before reaching a high level of toxicity that could be potentially harmful

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      Arel Zcirem Canimo 2 years ago

      08 AZ CANIMO BUHM1-2 15

      stoichiomistry is produced of weight and atomic weight. as a Hospitality Management student it helps us to calculate the foods or dishes that we can make with our available amount of ingredients in the kitchen. Stoichiometry is very important and helpful to my course because we should to know what kind of substance to add in another substance.

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      Sanguyo nicko 2 years ago

      The relevance of this in the field of Hospitality Management is we should be think what the guest will felt when we do an action. we should be maintain our good relationship in our guest.

    • mchristinelopez profile image

      mchristinelopez 2 years ago

      LOPEZ MARIE CHRISTINE , BUHM

      stoichiometry is important because it provides accurate ratios of the amounts of two substances required to react. Chemical equations are an indispensable way of representing reactions. They are routinely used to calculate masses of reactants and products.

    • Klaudine Bianca profile image

      2AlcantaraMMBUHM 2 years ago

      stoichiometry can help you find out the composition of molecules and general proportions of how to combine things to get them to react completely.Having the right proportions of things gets pretty important when you don't have a whole lot of reactants to waste cost reduction or when you're in the field of pharmacy (preventing overdose and death).

      02 Alcantara KB BUHM

    • Patricia Rivera profile image

      Patricia Rivera 2 years ago

      Patricia Rivera

      BSTM-1-1

      Stoichiometry is a section of chemistry that involves using relationships between reactants and/or products in a chemical reaction to determine desired quantitative data. In my field Stoichiometry is important because we need to know the safety pre cautions in making and preparing food also in airline industry in ticketing agent.

    • Cess Capulong profile image

      Cess Capulong 2 years ago

      Stoichiometry is applying math in everything does without even knowing it. Dialing our phones, searching through internet, parting in the streets, and slicing ingredients etc. It involves solving.

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      19 Garcia R. BUHM 2 years ago

      The stoichiometry is important in our life specially in my course because it help us to know different reaction when we use chemicals in hotel & restaurant.

    • Joyce De Guzman profile image

      Joyce De Guzman 2 years ago from San Ildefonso, Bulacan

      Stoichiometry is a section of chemistry that involves using relationships between reactants and/or products in a chemical reaction to determine desired quantitative data. In relation to our course, we often use chemicals and we should know the difference between the two, reatants and products and what products or reactants that may harm our beloved guest and customers.

    • Steph San profile image

      Steph San 2 years ago

      SANTIAGO STEPHANY BUHM

      We often use a stoichiometry calculation in everyday life without even realizing it, especially while cooking, preparing a grocery list or building something.

    • PatrickTan33BUHM profile image

      PatrickTan33BUHM 2 years ago

      33 TAN BUHM

      stoichiometry is Help in our field HM, because it can help us to know the kinds of chemicals that we will be using in cleaning. We can know of the chemicals that we are using are safe especially to our customer.

    • AlmiraEvangelista profile image

      AlmiraEvangelista 2 years ago

      Evangelista, Almira

      BSTM l-l

      Stochiometry has a connection in my field Tourism Management because it is about balancing and calculation. As a Tourism Student I must study how to balance my temper in interacting different attitudes of people.

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      kennethcorpuz 2 years ago

      stoichiomistry is produced of weight and atomic weight. and connect of tourism management because the food and beverage is chemical reaction and consider of weight about scientist learn of chemical from the calculate and many many processes and work of student tourism and connect of the kitchen like chicken kilos of food and etc..

    • gelo hernandez profile image

      gelo hernandez 2 years ago

      Hernandez Angelo BSHM

      Stoichiometry helps us to balance equations which is we need in our profession as a Hospitality Management student because it helps us to calculate the foods or dishes that we can make with our available amount of ingredients in the kitchen. We should really study Stoichiometry when you are taking the course Hospitality Management.

    • AndreaBarcita profile image

      AndreaBarcita 2 years ago

      3 BARCITA AR M. BUHM14

      Stoichiometry is important because in bartending we calculate the different kinds of drinks we examine if the percent of liquid is fine. If we put too much, the drink that we create might affect something to the guest.

    • Cea Castillo profile image

      Cea Castillo 2 years ago

      Stoichiometry is really important because it allows us to predict how much of reactant is consumed in a chemical reaction, or how much unwanted product is generated.

    • Johnrenz Santos profile image

      Johnrenz Santos 2 years ago from Candaba, Pampanga

      24 JRA SANTOS BSHM14

      Chemical Calculations one of the main heart of science all experiment that help and search for advancing of medical technology also student need to learn this kind of education in science.