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All About Matter
Upon completion of this lesson, the students should be able to:
- describe the classification of matter
- identify the properties of matter
- compare the changes of matter
- distinguish the different laws governing matter
Nature shows itself to us in two different ways: as matter and as energy. All objects are composed of matter. Objects may differ widely from one another. But they have one thing in common – they all occupy space. Scientists usually define matter as anything that occupies space. All matter has inertia. This means that it resists any change in its condition of rest or of motion. Mass is the quantity of matter in an object. According to scientists, mass is a measure of inertia. The gravitational attraction of the earth for a given mass gives matter its weight. Gravity’s pull on an object decreases as it moves away from the center of the earth. Because of this, object that moves from the earth into outer space “lose weight” even though their masses remain the same.
When people, animals and machines work, when we feel the heat from the sun, or see light from the electric bulb, we become aware of energy. All of these involve energy. Scientists define energy as the ability to do work, or to move matter. The most familiar form of energy is heat. All other kinds of energy maybe changed into heat. Matter can be changed into energy and energy into matter.
Classification of Matter
Matter is classified according to origin or source, state and composition.
According to the origin or source, matter is classified as organic and inorganic matter. Organic matter comes from living things, while inorganic matter comes from non-living things.
Chemists have studied that all forms of matter may be classified into three general classes on the basis of their compositions. These are the elements, compounds and mixtures.
- Element is a substance, which cannot be decomposed by ordinary means. Atom is the smallest part of an element that can enter into combination with other elements.
- Compound is a substance, which can be decomposed into two or more simpler substances by ordinary chemical means.
- Mixture is a material composed of two or more substances each of which retains its own characteristic properties. a. Heterogeneous mixture is one which has parts possessing different properties. b. Homogeneous mixture is one which has similar properties throughout. Substance is a homogeneous material composed of one particular kind of matter.
Classification of Matter
Physical States of Matter
Matter can ordinarily exist in three physical states – solid, liquid, and gas. A fourth state of matter exists under special conditions, called plasma.
- Solid has definite shape and volume has the greatest amount of mass per unit of volume or density. It has form, hardness or rigidity, or the ability to oppose a change of shape. The atoms in almost all solids are arranged in regular patterns, called crystals.
- Liquid assumes the shape of its container and has definite volume. It takes the shape of its container in which it is placed. It fills it only when its volume equals that of the container. Examples are water, oil, and gasoline.
- Gas has no definite shape and volume. Because of its free-flowing characteristic of liquids and gasses, it is known collectively as fluid.
- Plasma make up the fourth state of matter and cannot be seen by people in their everyday lives. Plasmas are formed in the interior of stars, in outer space, and in some laboratory experiments. Plasmas result when the atoms in a gas become ionized (electrically charged). Electrical forces between the gas atoms give the gas new physical properties.
Learn about the states of matter, solids, liquids and gases, how they're different and where they're found in everyday life.
Physical States of Matter
Properties of Matter
Matter can be recognized in terms of characteristics or properties.
A. Physical Properties
We recognize certain kinds of matter by its properties: specific and accidental.
Specific properties are those features, which definitely distinguish one substance from another. Some of these are the following:
1. Density is the weight of a unit volume of a substance.
2. Specific gravity is the ratio of the weight of a given volume of a substance to the weight of the same volume of water at the same temperature.
3. Hardness is the ability of the substance to resist scratching.
4. Odor is the characteristics odor of a given substance.
5. Color is the characteristics color of a given substance.
Accidental physical properties are those features as weight, dimensions, and volume. They have nothing to do with the nature of the substance, but they enable us to find out how much of a given substance we have.
B. Chemical Properties
Chemical properties of a substance describe how a substance acts when it undergoes change. They describe its ability to form new substances under given conditions. A chemical change or a chemical reaction is a change from one substance to another. Nevertheless, the chemical properties of a substance may be considered to be a listing of all the chemical reactions of a substance and the conditions under which the reactions occur. Some of the chemical properties are: combustibility, stability, relative activity, response to test reaction, and ionization.
The Physical Properties and Chemical Properties of Matter - Chemistry
Intrinsic and Extrinsic Properties
- Intrinsic (intensive) Properties are properties that do not depend on the size of the sample. Examples are color, odor, boiling point, and electrical conductivity.
- Extrinsics (Extensive) Properties are properties that depend on the size or amount of the sample. Examples are mass and volume.
Changes in Matter
Physical Changes are those in which the identifying properties of substances remain unchanged. Examples are melting of ice, boiling of water and freezing of liquids.
Chemical Changes are those in which new substances with new properties are formed. Examples are burning of woods, rusting of iron and decaying of plants.
Chemical changes involve energy. Substances possess energy because of their composition and structure. This is a kind of potential energy, which chemists generally refer to as chemical energy. Any chemical change, which absorbs heat energy as it progresses, is said to be endothermic. An example is the production of calcium carbide in the intense heat of the electric furnace. Any chemical change, which liberates heat energy as it proceeds, is said to be exothermic. An example is the burning of fuels.
Law of Conservation of Mass
The Law of Conservation of Mass state that mass is neither created nor destroyed. An example is shown in the complete combustion of gasoline. The relationship is true within the limits of one’s ability to determine the weights of the reacting substances and the products of the reaction:
Gasoline + oxygen ----> carbon dioxide + water vapor
Weight of reactants weight of products
Law of Definite Proportion
The Law of Definite Proportion states that any pure compound is always composed of the same elements combined in a proportion by weight.
Water always contains 8 parts by weight of oxygen to 1 part by weight of hydrogen.
O = 16/18 x 100% = 88.88%
H = 2/18 x 100% = 11.11%
Law of Multiple Proportions
The Law of Multiple Proportion states that when the same two elements unite to form two or more different compounds, if the amount of one element is constant, the weights of the other element in the series of compounds will be in the ratio of small whole numbers.
H2O = 1g of H and 8g of O
H2O2 = 1g of H and 16g of O
Properties of Matter
The Properties of Matter The general properties of matter result from its relationship with mass and space. Because of its mass, all matter has
- States of Matter -- Solid, Liquid, Gas, Plasma
I. Identify whether the following are physical or chemical changes:
___________________1. welding metals
___________________2. ripening of fruits
___________________3. grinding rice
___________________4. dissolving sugar in water
___________________5. burning gas
___________________6. magnetizing iron nails
___________________7. melting of butter
___________________8. hair bleaching
___________________9. souring of milk
___________________10. brewing of coffee
II. Classify the following as either an element, a compound, or a mixture:
___________________2. dry ice
___________________3. aluminum wire
___________________5. lead pencil
___________________10. rubbing alcohol
III. Classify the following properties as intrinsic or extrinsic:
___________________5. freezing point
___________________6. electrical conductivity
___________________9. boiling point
IV. Answer the following:
- Name several substances that exist in all three states of matter.
- State the following: Law of Conservation of Mass, Law of Definite Proportion, and the Law of Multiple Proportions.
- What do you think is the reason why iron and sulfur unite in definite proportions to form iron sulfide?
- How do you decide whether a certain change is physical or chemical?