# Free PRAXIS II Physics and Chemistry Science Study Guide

Updated on March 19, 2014

## How to Pass the Science PRAXIS II Test | Practice PRAXIS II Questions | Chemistry & Physics PRAXIS II Study Guide

This PRAXIS II study guide specifically covers the chemistry and physics portions of the PRAXIS II Middle School Science (0439) and PRAXIS II General Science: Content Knowledge (0435) exams.

Here you'll find detailed information about physics and chemistry, which can also help you prepare for the PRAXIS II Chemistry: Content Knowledge (0245) and PRAXIS II Physics: Content Knowledge (0265) exams.

Since the PRAXIS II science exams measure your knowledge of so many scientific topics, this free PRAXIS II study guide is split into four parts. Click to visit Part 1, Part 2 and Part 3 of the study guide!

Image Credit: zhouxuan12345678

Though this portion of the study guide is still under construction, I've decided to share it anyway because what is already complete will help aspiring science teachers pass their PRAXIS II exams. Check back soon for the complete Physics and Chemistry study guide!

## 100% Original Content

I created this study guide when preparing to take the PRAXIS II Middle School Science (0439) exam. I used a variety of sources to research these topics and rewrote what I learned in my own words. No part of this study guide has been copied from Wikipedia or any other source.

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## Physics: Mechanics

### Motion, Newton's Laws, Weight, Mass, Friction, Work, Energy, Power, Simple Machines, Momentum, Gravity and Fluids

A. Demonstrate understanding of (the variables involved in) straight-line motion, projectile motion, circular motion, and periodic motion

• STRAIGHT-LINE MOTION:
• PROJECTILE MOTION:
• CIRCULAR MOTION:
• PERIODIC MOTION:
B. Demonstrate understanding of Newton's laws of motion
• NEWTON'S LAWS OF MOTION:
C. Distinguish between weight and mass
• WEIGHT:
• MASS:
D. Demonstrate understanding of friction
• FRICTION:
E. Distinguish among work, energy, and power
• WORK:
• ENERGY:
• POWER:
F. Demonstrate understanding of simple machines and torque
• SIMPLE MACHINES:
• TORQUE:
G. Demonstrate understanding of linear momentum
• LINEAR MOMENTUM:
H. Demonstrate understanding of the conservation of energy and the conservation of linear momentum
• CONSERVATION OF ENERGY:
• CONSERVATION OF LINEAR MOMENTUM:
I. Demonstrate understanding of angular momentum and angular momentum conservation
• ANGULAR MOMENTUM:
• ANGULAR MOMENTUM CONSERVATION:
J. Demonstrate understanding of the force of gravity
• GRAVITY:
K. Demonstrate understanding of pressure and Pascal's principles for fluids
• PRESSURE:
• PASCAL'S PRINCIPLES FOR FLUIDS:
L. Demonstrate understanding of Archimedes' principle (buoyancy)
• ARCHIMEDES' PRINCIPLE:
M. Demonstrate understanding of Bernoulli's principle for fluids
• BERNOULLI'S PRINCIPLE FOR FLUIDS:

## Physics: Electricity & Magnetism

### Electric Charges, Currents, Circuits, Ohm's Law, EMF, Magnets, Transformers and Motors

A. Demonstrate understanding of the repulsion and attraction of electric charges

B. Demonstrate understanding of the characteristics of current electricity and simple circuits (for example, resistance, and Ohm's law, electromotive force, potential difference capacitance, current)

• RESISTANCE:
• OHM'S LAW:
• ELECTROMOTIVE FORCE:
• POTENTIAL DIFFERENCE CAPITANCE:
• CURRENT:
C. Compare and contrast series and parallel circuits
• SERIES CIRCUITS:
• PARALLEL CIRCUITS:
D. Compare and contrast conductors and insulators
• CONDUCTORS:
• INSULATORS:
E. Apply Ohm's law to series and parallel circuits

F. Compare and contrast direct current and alternating current

• DIRECT CURRENT:
• ALTERNATING CURRENT:
G. Identify sources of EMF (for example, batteries, photo cells, generators)
• SOURCES OF ELECTROMOTIVE FORCE:
H. Demonstrate understanding of magnets, magnetic fields, and magnetic forces
• MAGNETS:
• MAGNETIC FIELDS:
• MAGNETIC FORCES:
I. Demonstrate understanding of how transformers and motors work
• TRANSFORMERS:
• MOTORS:

## Physics: Waves

### Transverse & Longitudinal Waves, Light, Doppler Effect, Polarization, Sound, Color and the Electromagnetic Spectrum

A. Define and use the terms speed, amplitude, wavelength, and frequency

• SPEED (v): a scalar quantity that defines how fast something is moving; measures the rate of change in distance over time; unlike velocity, there is no direction associated with speed; v = d/t;
• AMPLITUDE (a): the maximum displacement of the medium from its equilibrium
• WAVELENGTH (l): the distance between two corresponding points on a wave train
• CYCLE: one complete pattern of wave, vibration or other periodic phenomenon
• PERIOD (T): the time it takes to complete one cycle; measured per second (s); period is inversely proportional to frequency; T=1/f;
• FREQUENCY (f): the number of cycles completed per unit time (usually per second); the frequency of a wave is inversely proportional to its period (f = 1/T); measured in hertz (1 Hz = 1 cycle/second);
B. Distinguish between the characteristics of transverse and longitudinal waves
• TRANSVERSE WAVES: a wave in which the medium vibrates - like a jump rope - in a direction perpendicular to the direction in which the wave travels (i.e. light)
• LONGITUDINAL WAVES: a wave in which the medium vibrates - like a slinky - in a direction parallel to the direction in which the wave travels (i.e. sound)
C. Demonstrate understanding of reflection, refraction, dispersion, absorption, transmission, scattering, and superposition
• REFLECTION: occurs when light bounces off of a surface; all surfaces are reflective;
• INCIDENT RAY: the ray of light that strikes a reflective surface
• REFLECTED RAY: the ray of light that bounces back from a reflective surface
• ANGLE OF INCIDENCE: the angle between the normal (a line perpendicular to the reflective surface) and the incident ray; angle of incidence = angle of reflection;
• ANGLE OF REFLECTION: the angle between the normal and the reflected ray
• REFRACTION: the bending of light as it passes from one medium into another; occurs when some of the incident ray travels through rather than bounces back from a surface; results from light traveling at different speeds through different media;
• light refracts toward the normal when moving into a denser medium (gas > liquid)
• light refracts away from the normal when moving into a less dense medium (liquid > gas)
• INDEX OF REFRACTION (n): a measure of how much the speed of light is reduced while traveling through a particular substance; transparent materials (air, water, glass) have lower indices of refraction than denser materials;
• DISPERSION: a refractive process by which polychromatic (multicolored) light is separated into its constituent colors; the spectrum produced by a prism is a result of dispersion;
• ABSORPTION: the transfer of a wave's energy to the matter through which it passes
• the energy of a wave is equal to the square of its amplitude
• transparent substances absorb only a small fraction of a wave's energy
• opaque substances absorb all of a wave's energy
• substances are selectively absorptive (i.e. green glass is transparent to green light but opaque to red and blue light; rubber is transparent to infrared and X rays but opaque to visible light)
• TRANSMISSION:
• SCATTERING: the color of the sky is a direct result of scattering;
• SUPERPOSITION: two or more waves in the same place are superimposed upon one another; proves that one wave cannot alter the direction, frequency, wavelength or amplitude of another;
D. Demonstrate understanding of diffraction and interference
• DIFFRACTION: the bending of light around obstacles
• INTERFERENCE: the effect produced by two or more waves passing simultaneously through a region
• CONSTRUCTIVE INTERFERENCE: the amplification of one wave by another identical wave; ocurrs when interfering waves are "in phase;"
• DESTRUCTIVE INTERFERENCE: the cancellation of one wave by another; both waves remain in tact once they have passed each other;
E. Demonstrate understanding of the Doppler Effect
• DOPPLER EFFECT: the variation in observed frequency caused by the relative motion between a source and a receiver
• the observed f increases when the distance between a source and a receiver decreases
• the observed f decreases when the distance between a source and a receiver increases
• changes in sound frequency are observed as changes in pitch
• changes in light frequency are observed as changes in color
F. Demonstrate understanding of polarization
• POLARIZATION: a process that aligns a wave of light so that it oscillates in one dimension rather than two
• transverse waves can be polarized
• longitudinal waves cannot be polarized
• does not affect the direction of a wave
G. Recognize the characteristics of sound waves (for example, pitch, loudness, speed)
• PITCH:
• LOUDNESS:
• SPEED:
H. Demonstrate understanding of how sound waves are produced by the vibrations of air columns and strings

I. Characterize the electromagnetic spectrum (gamma rays to radio waves)

• ELECTROMAGNETIC SPECTRUM:
• RADIO WAVES: longest length; lowest frequency;
• MICROWAVES:
• INFRARED RAYS:
• ROYGBIV: visible light
• ULTRA-VIOLET RAYS:
• X RAYS:
• GAMMA RAYS: shortest length; highest frequency;
J. Demonstrate understanding of color and the visible spectrum (for example, addition and subtraction, relationship to wave frequency)

K. Demonstrate understanding of geometric optics (mirrors, lenses, prisms, fiber optics)

• MIRRORS:
• LENSES:
• PRISMS:
• FIBER OPTICS:

## The Cartoon Guide to Chemistry

The Periodic Table of Elements

A. Demonstrate understanding of the meaning of chemical periodicity

• CHEMICAL PERIODICITY:

B. Demonstrate understanding of periodic trends in chemical and physical properties

• GROUP: columns;
• PERIOD: rows;

## Chemistry: The Mole & Chemical Bonding

### Mole Concept, Chemical Composition, Chemical Formulas, Organic & Inorganic Compounds, Bonds and Electron Dot Diagrams

A. Demonstrate understanding of the mole concept and chemical composition

• MOLE CONCEPT:
B. Interpret and use chemical formulas
• CHEMICAL FORMULAS:
C. Demonstrate understanding of the systematic nomenclature of inorganic compounds

D. Demonstrate understanding of the nomenclature of simple organic compounds

E. Identify the various types of bonds

• IONIC BONDS: occur when two or more oppositely charged atoms exchange electrons to create a negative ion (ANION) and a positive ion (CATION)
• occur between atoms with low electronegativity (mostly empty valence shells) and high electronegativity (mostly full valence shells)
• form between metals and nonmetals
• ionic compounds dissolve easily in water and other polar solvents, conduct electricity in solution and tend to form crystalline solids with high melting temperatures
• Example: sodium chloride; sodium gives up its one valence electron to chlorine, which needs only one electron to complete its shell; the oppositely charged ions are then held together by electrostatic forces;
• COVALENT BONDS: occur when two or more atoms share electrons
• NONPOLAR COVALENT BONDS: occur when atoms share electrons equally; example: when two atoms of the same element bond;
• POLAR COVALENT BONDS: occur when atoms share electrons unequally; example: water molecules;
• covalent molecules are not strongly attracted to each other and exist primarily as liquids or gases
• commonly occur between nonmetals, which have a tendency to gain electrons;
• Example: hydrogen atoms, which have one valence electron
• HYDROGEN BONDS: occur when the partially charged regions of polar molecules like water are electrostatically attracted to the oppositely charged regions of other polar molecules; weaker than a covalent bond;
• Example: multiple hydrogen bonds hold together the DNA double helix
F. Interpret electron dot and structural formulas
• ELECTRON DOT DIAGRAMS: use dots to visually depict an atom's valence electrons (which can be determined by an element's group number on the periodic table) and the bonds they form
• STRUCTURAL FORMULAS: use lines to visually depict an atom's valence electrons and the bonds they form

## Chemistry: The Kinetic Theory & States of Matter

### Kinetic Molecular Theory, Phase Changes, Gases and Crystals

A. Demonstrate understanding of kinetic molecular theory

• KINETIC MOLECULAR THEORY: states that (1) gases are composed of molecules that behave like hard, spherical objects in a state of constant, random motion; (2) these molecules have negligible volume; (3) these molecules do not attract or repel each other; (4) collisions between these molecules are perfectly elastic, meaning energy is neither gained nor lost; (5) the average kinetic energy of the gas molecules is directly proportional to the absolute temperature of the gas;
B. Demonstrate understanding of phase changes
• PHASE CHANGES: the conversion of a material from one physical state to another
• FREEZING: liquid > solid
• MELTING: solid > liquid
• CONDENSATION: gas > liquid
• VAPORIZATION: liquid > gas (occurs at the boiling point)
• EVAPORATION: liquid > gas (occurs below the boiling point)
• SUBLIMINATION: solid > gas
C. Demonstrate understanding of the relationships among temperature, pressure, volume, and number of molecules of a gas
• IDEAL GAS LAW: PV=nRT (PV/T is constant)
• P = pressure
• V = volume
• n = moles of a gas
• R = universal gas constant
• T = absolute temperature
• TEMPERATURE: the average kinetic energy of the gas molecules is directly proportional to the absolute temperature of the gas; temperature increases as pressure increases and vice versa;
• PRESSURE: arises from the force exerted by gas molecules as they collide with the walls of a container; pressure increases as volume decreases and vice versa;
• VOLUME: volume increases as pressure decreases and vice versa; volume increases when temperature increases;
• NUMBER OF MOLECULES: the number of molecules remains constant despite temperature, pressure and volume
D. Demonstrate understanding of the characteristics of crystals
• CRYSTALS: a solid material whose atomic structure is arranged in an orderly, repeating and three-dimensional pattern (i.e. gemstones, metals); commonly formed by the cooling of magma and the evaporation of mineral-rich solutions; the slower the formation process, the larger the crystal;

## Chemistry: Chemical Reactions

### Chemical Equations, Chemical Reactions and Electrochemistry

A. Demonstrate ability to balance chemical equations

• Example A: _ C2H6 + _ O2 >> _ H2O + _ CO2 = 2 C2H6 + 7 O2 >> 6 H2O + 4 CO2
• Example B: _ NH3 + _ O2 >> _ NO + _ H2O = 4 NH3 + 5 O2 >> 4 NO + 6 H2O
B. Identify the various types of chemical reactions
• CHEMICAL REACTIONS:
• COMBUSTION: occurs when oxygen combines with another compound to form water and carbon dioxide; exothermic;
• Example: the burning of naphthalene ... C10H8 + 12 O2 >> 10 CO2 + 4 H2O
• SYNTHESIS: occurs when two or more simple compounds combine to form a more complicated one (A + B >> AB)
• Example: the combination of iron and sulfur to form iron sulfide ... 8 Fe + S8 >> 8 FeS
• DECOMPOSITION: occurs when a complex compound breaks down into simpler parts (AB >> A + B)
• Example: the electrolysis of water into oxygen and hydrogen gas ... 2 H2O >> 2 H2 + O2
• SINGLE DISPLACEMENT: occurs when one element trades places with another in a compound (A + BC >> AC + B)
• Example: the combination of zinc with hydrochloric acid ... Zn + 2 HCl >> ZnCl2 + H2
• DOUBLE DISPLACEMENT: occurs when the anions and cations of two different molecules switch places, forming two entirely different compounds (AB + CD >> AD + CB)
• Example: the combination of sodium chloride and silver nitrate to form sodium nitrate and silver chloride ... NaCl(aq) + AgNO3(aq) >> NaNO3(aq) + AgCl(s)
• ACID-BASE: a special kind of double displacement reaction that occurs when the H+ ion of an acid reacts with the OH- ion of a base; typically produces ionic salt and water;
• Example: the combo of hydrobromic acid and sodium hydroxide ... HBr + NaOH >> NaBr + H2O
C. Distinguish between endothermic and exothermic chemical reactions
• ENDOTHERMIC: reactions that absorb energy (i.e. photosynthesis); cannot occur spontaneously;
• EXOTHERMIC: reactions that release energy in the form of heat, light or sound (i.e. the combination of sodium and chlorine to create table salt); may occur spontaneously;
D. Demonstrate understanding of the effects of temperature, pressure, concentration, and the presence of catalysts on chemical reactions
• FACTORS THAT AFFECT CHEMICAL REACTIONS:
• TEMPERATURE: an increase in temperature speeds up a reaction because molecules possess more thermal energy at a higher temperature; a reaction's rate will typically double for each 10*C rise in temperature;
• PRESSURE: an increase in pressure increases the concentration, therefore raising the reaction rate;
• CONCENTRATION: a high concentration of reactants raises the reaction rate by increasing the number of molecular collisions;
• CATALYSTS: the presence of catalysts lowers the activation energy of a reaction and ultimately increases the reaction rate;
E. Demonstrate understanding of practical applications of electrochemistry
• ELECTROCHEMISTRY:

## Chemistry: Solutions & Solubility

### Solutions, Solvents, Solubility, Acids, Bases, Salts, pH and Buffers

A. Demonstrate understanding of solution terminology and distinguish among types of solutions

B. Demonstrate understanding of various types of solvents and factors affecting the dissolving process

C. Demonstrate understanding of the effect of temperature and pressure on the solubility of a solute

D. Demonstrate understanding of the physical and chemical properties of acids, bases, and salts

• ACIDS:
• BASES:
• SALTS:
E. Demonstrate knowledge of the meaning of pH and the effects of buffers
• pH: a measure of a solution's acidity; the pH scale ranges from 0 (very acidic; i.e. battery acid) to 14 (very alkaline; i.e. bleach); a pH of 7 is neutral (i.e. water);
• BUFFERS: solutions that resist changes in pH when small quantities of an acid or base are added to it; used to maintain a certain pH level; example: blood;
• ACIDIC BUFFERS: composed of a weak acid and its conjugate base; pH < 7;
• ALKALINE BUFFERS: composed of a weak base and its conjugate acid; pH > 7;

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