GEN CHEM 162 EXAM 1 QUESTIONS
AND ANSWERS
Solution - ANSWER-a homogeneous mixture (uniform and consistent composition
throughout the sample) composed of solute(s) dissolved in a solvent
Solubility - ANSWER-Amount of a substance (solute) that dissolves in another (solvent)
Soluble - ANSWER-When one substance (solute) dissolves in another (solvent)
Ex: NaCl in water
Miscible - ANSWER-Describes two liquids that are soluble in each other (a solute liquid
dissolves in solvent liquid)
Insoluble - ANSWER-When one substance (solute) doesn't dissolve in another (solvent)
Ex: Oil in water (creates two distinct layers)
Common polar solvents - ANSWER-Water (H2O)
Acetone (CH3COCH3)
Methanol (CH3OH)
Ethanol (CH3CH2OH)
Factors Impacting Collision Rate - ANSWER-1. Concentration of Reactants (higher
concentration= more frequent collisions)
2. Temperature of Reaction (higher temperature= more frequent and more energetic
collisions)
3. Structure and Orientation of Colliding Particles (particles must have correct
orientation to be able to react)
Generalized Reaction Rate (aA + bB --> cC + dD) - ANSWER--1/a (ΔA/ΔT)= -1/b
(ΔB/ΔT)= 1/c (ΔC/ΔT)= 1/d (ΔD/VT)
*Multiply reactants by a negative since their concentrations decrease over time*
the order of a reactant reflects - ANSWER-the rate's sensitivity to changing that
reactant's concentration
i.e. rates of reactions with high orders are much more sensitive to changes in
concentration
Rate Constant Units - ANSWER-Zero order: M/s
First order: 1/s
, Second order: 1/ M*s
Zero order reaction - ANSWER-rate=k[A]^0 --> rate=k
k units: M/s
reaction rate is independent of concentration
First order reaction - ANSWER-rate=k[A]^1
k units: 1/s
rate is directly proportional to the reactant concentration
Rate of first-order reaction decreases as the reaction proceeds since the concentration
of reactant decreases
Second order reaction - ANSWER-rate=k[A]^2
k units: 1/Ms
rate is directly proportional to the square of the reactant concentration
Rate of 2nd order is more sensitive to changes in the concentration of a first-order
reaction
Reaction Plots - ANSWER-Zero-order: rate is constant (horizontal line)
First-order: rate slows down at constant (linear)
Second-order: rate slows down at a faster pace
Integrated Rate Law - ANSWER-Used for determining the amount of reaction
present/remaining at a certain time (only used for reactions with one reactant)
Linear Relationships of Integrated Rate Laws - ANSWER-Zero order: [A]t v. t, slope= -k
First Order: ln[A]t v. t, slope= -k
Second Order: 1/[A]t v. t, slope= k
Half life - ANSWER-the amount of time it takes for an initial concentration of a species
to decrease by 50%
Zero Order Half Life Equation - ANSWER-t1/2 = [A]k
First Order Half Life Equation - ANSWER-t1/2 = ln2/k
Second Order Half Life Equation - ANSWER-t1/2 = 1 / k[A]0
Successive Half Lives - ANSWER-Zero Order: time decreases by x2
First Order: no change in time (concentration is constant)
Second Order: time increase by x2
Activation Energy (Ea) - ANSWER-the minimum amount of energy required to initiate a
chemical reaction (energy needed to overcome the activation barrier of a reaction)
- ENDOTHERMIC (energy must be supplied)
- large Ea= slow reaction
AND ANSWERS
Solution - ANSWER-a homogeneous mixture (uniform and consistent composition
throughout the sample) composed of solute(s) dissolved in a solvent
Solubility - ANSWER-Amount of a substance (solute) that dissolves in another (solvent)
Soluble - ANSWER-When one substance (solute) dissolves in another (solvent)
Ex: NaCl in water
Miscible - ANSWER-Describes two liquids that are soluble in each other (a solute liquid
dissolves in solvent liquid)
Insoluble - ANSWER-When one substance (solute) doesn't dissolve in another (solvent)
Ex: Oil in water (creates two distinct layers)
Common polar solvents - ANSWER-Water (H2O)
Acetone (CH3COCH3)
Methanol (CH3OH)
Ethanol (CH3CH2OH)
Factors Impacting Collision Rate - ANSWER-1. Concentration of Reactants (higher
concentration= more frequent collisions)
2. Temperature of Reaction (higher temperature= more frequent and more energetic
collisions)
3. Structure and Orientation of Colliding Particles (particles must have correct
orientation to be able to react)
Generalized Reaction Rate (aA + bB --> cC + dD) - ANSWER--1/a (ΔA/ΔT)= -1/b
(ΔB/ΔT)= 1/c (ΔC/ΔT)= 1/d (ΔD/VT)
*Multiply reactants by a negative since their concentrations decrease over time*
the order of a reactant reflects - ANSWER-the rate's sensitivity to changing that
reactant's concentration
i.e. rates of reactions with high orders are much more sensitive to changes in
concentration
Rate Constant Units - ANSWER-Zero order: M/s
First order: 1/s
, Second order: 1/ M*s
Zero order reaction - ANSWER-rate=k[A]^0 --> rate=k
k units: M/s
reaction rate is independent of concentration
First order reaction - ANSWER-rate=k[A]^1
k units: 1/s
rate is directly proportional to the reactant concentration
Rate of first-order reaction decreases as the reaction proceeds since the concentration
of reactant decreases
Second order reaction - ANSWER-rate=k[A]^2
k units: 1/Ms
rate is directly proportional to the square of the reactant concentration
Rate of 2nd order is more sensitive to changes in the concentration of a first-order
reaction
Reaction Plots - ANSWER-Zero-order: rate is constant (horizontal line)
First-order: rate slows down at constant (linear)
Second-order: rate slows down at a faster pace
Integrated Rate Law - ANSWER-Used for determining the amount of reaction
present/remaining at a certain time (only used for reactions with one reactant)
Linear Relationships of Integrated Rate Laws - ANSWER-Zero order: [A]t v. t, slope= -k
First Order: ln[A]t v. t, slope= -k
Second Order: 1/[A]t v. t, slope= k
Half life - ANSWER-the amount of time it takes for an initial concentration of a species
to decrease by 50%
Zero Order Half Life Equation - ANSWER-t1/2 = [A]k
First Order Half Life Equation - ANSWER-t1/2 = ln2/k
Second Order Half Life Equation - ANSWER-t1/2 = 1 / k[A]0
Successive Half Lives - ANSWER-Zero Order: time decreases by x2
First Order: no change in time (concentration is constant)
Second Order: time increase by x2
Activation Energy (Ea) - ANSWER-the minimum amount of energy required to initiate a
chemical reaction (energy needed to overcome the activation barrier of a reaction)
- ENDOTHERMIC (energy must be supplied)
- large Ea= slow reaction
