IB Chemistry SL Final Review

Atomic Theory

All matter is composed of atoms. Atoms can’t be created or destroyed and are instead rearranged.

Matter

Something that occupies space, has a mass, and is made up of particles, atoms, or molecules

Solids

• fixed shape and volume

• can’t be compressed

• attractive forces between particles hold particles in a closed-pack arrangement

• particles vibrate in fixed condition

liquids

• fixed volume, but no fixed shape

• can’t be compressed

• forces between particles are weaker than solids

• particles vibrate, rotate, and translate(move around)

Gases

• no fixed volume or shape

• can be compressed

• forces between particles are taken at zero

• particles vibrate, rotate, and translate faster than a liquid

Absolute Zero

The temperature at which all movement of particles stops. It is zero on the kelvin scale(-273°C).

Condensation

gas →liquid

Freezing

liquid →solid

Vaporization

liquid →gas

Evaporation

vaporization at temperatures below boiling points

sublimation

solid →gas

deposition

gas →solid

melting

solid → liquid

Which changes of state are exothermic?

condensation, freezing, and deposition

Which changes of state are endothermic?

evaporation, melting, and sublimation

element

contains an atom of one type

compound

two or more elements bonded together in a fixed ratio

particle

smallest unit of something

mixture

2+ types of particles

pure substance

1 substance only, has constant composition, and chemical properties are distant and consistent

homogeneous mixture

can’t see the difference, uniform composition and properties

heterogeneous mixture

can see difference, non-uniform

ions

charged particle. Unequal number of electrons and protons

cation

positively charged ions

anion

negatively charged ions

synthesis reaction

reactions involving combination of two or more substances to produce a singular product(A + B → AB)

Decomposition reaction

reactions involving a single compound of being broken down into two or more particles(AB → A + B)

Single replacement reaction

reactions occur when one element replaces another in a compound(A + BC → B + AC)

Double replacement reaction

two compounds on the reaction side and two compound on the product side switch. Form insoluble substances and weak or non-electrolytes(AB + CD → AD + BC)

Combustion

reaction with organic material and O2 to produce carbon dioxide/monoxide and water vapor(CH4 + O2 → CO2 + H2O)

chemical stoichiometry

relationship between the amounts of the reactants and products in a chemical reaction

Avogadro’s Constant

6.022 x 10^23 mol^-1

Mol

fixed amount of a substance. Can be applied to atoms, molecules, etc.

Isotopes

atoms of the same element that have the same number of protons, but a different number of neutrons. Have different mass number

Relative Abundance

measure of percentage of each isotope that occurs in a natural sample of the element

Relative Atomic Mass(Ar)

Mass of an atom relative to the 12C isotope having a value of 12

Relative Molecular Mass(Mr)

determined by combining Ar values of the individual atoms or ions

True or False? If the question asks for “relative” something, you don’t put units

true

Molar mass

mass of one mole of a substance with the unit gmol^-1

How do you calculate moles?

• mols = mass/molar mass

• mols = molarity x volume

empirical formula

simple whole number ratio of atoms or amount(in mols) of each element present in a compound

molecular formula

actual number of atoms or amount(in mols) of elements in one structural unit or one mole of a compound

stoichiometry

quantitative measure of examining the relative amounts of reactants and products

limiting reactant

most expensive reactant

solution

homogeneous mixture of where one substance dissolved in another

solute

gets dissolved by the solvent

solvent

does dissolving of another substance

True or False? When water is a solvent, it is an aqueous solution

true

molar concentration

amount of substance dissolved in 1dm^3 of solvent

percent yield equation

experimental yield/theoretical yield x 100%

Kinetic Theory of Gas

1. gases are made up of very small particles, separated by large distances. Most of the volume occupied by a gas is empty space

2. Gaseous particles are constantly moving in straight lines, but random directions

3. Gaseous particles undergo elastic collisions with each other and the walls of the container. No loss of kinetic energy occurs

4. Gaseous particles exert no force of attraction on other gases

Avogadro’s Law

equal volumes of any gas measured at the same temperature and pressure contain the same number of molecules

Boyle’s Law

inverse relationship between pressure and volume

Charlie's Law

Direct relationship between volume and temperature

Gay-Lussac’s Law

Direct relationship between pressure and temperature

Ideal gas equation

pV = nRT (R= 8.31 JK^-1 mol^-1)

Rate of reaction

the change in concentration of reactants or products per unit time

How can you measure a change in concentration?

1. Change in pH(acid-base reactions)

2. Change in conductivity(reaction involving electrolytes)

3. Change in mass or volume(reactions involving solid or gas)

4. Change in color(reactions involving transition metals)

True or False? When t=0, the instantaneous rate = the initial rate

true

activation energy

The minimum kinetic energy of colliding particles required for a successful collision

Collision Theory

1. Particles must collide

2. Particles must collide with sufficient energy

3. Particles must collide with the proper orientation

What factors affect collision rate?

• concentration

• surface area

• gas

• temperature

• catalyst

How does increasing surface area affect reaction rates?

More surface area means more area fort the particles to be in contact and therefore increase collisions.

How does concentration of reactants affect reaction rates?

With more particles, the particles have a greater chance of colliding and therefore a greater chance of successfully colliding.

How does pressure(for gas) affect reaction rates?

Increasing the pressure is the same as increasing concentration. Collision frequency increases

How does temperature affect reaction rates?

As temperature increases, the rate of reaction exponentially increases. Molecules have more energy and move faster. Higher frequency of particles colliding and they collide harder. Increases the number of particles that will have sufficient activation energy.

catalysts

Increases the rate of reaction without being consumed in the reaction. Lowers the activation energy.

Intermediate

unstable species formed temporarily during a reaction

homogeneous catalysts

In the same physical state as the reactants

heterogeneous catalysts

in different states as the reactants

True or False? A change in color, temperature, and volume can all be used to measure the rate of reaction.

False. Only a change in color and temperature can be used

True or False? The activation energy of a reaction is NOT affected by temperature

true

Equilibrium

Both forward and reverse reactions occur simultaneously with products and reactants constantly being interconverted

Dynamic Equilibrium

Macroscopic properties are constant(concentrations of all reactants and products remain constant) and the rate of the forward reaction is equal to the rate of the reverse reaction

The relative rate of forward and reverse reactions depend on…

• temperature

• pressure

• concentration

• catalyst

True or False? At equilibrium, forward and reverse reactions occur at equal rates

True

True or False? At equilibrium there is a change in the concentration or reactants and products

False

True or false? At equilibrium, there is a change in properties such as color and density?

false

True or False? At equilibrium the reaction can be approached from either the forward or reverse direction

true

Equilibrium Constant Equation

Kc = [products]/[reactants]

If K>1

products are favored

If K<1

reactants are favored

If ΔH = -KJ then the forward reaction is ___ and KJ will be on the _____ side

exothermic, product

If ΔH = +KJ then the forward reaction is ___ and KJ will be on the _____ side

endothermic, reactant