Chem 106 Exam 3 Notes review With Correct
Answers
1st order rate law - Correct Answer -Rate = k[A]; linear
2nd order rate law - Correct Answer -rate = k[A]^2; nonlinear
1st order half life - Correct Answer -time required for 1/2 of reactant to react
radioactive decay - Correct Answer -The breakdown of a radioactive element, releasing particles and
energy
well known 1st order process; radioactive isotopes characterized according to half life (carbon dating)
collision model - Correct Answer -a model based on the idea that molecules must collide to react; used
to account for the observed characteristics of reaction rates
only certain orientations lead to reactions
What does k depend on in the Arrhenius Equation? - Correct Answer -1. fraction of molecules w/ Ea or
greater
-Maxwell-boltzmann distribution
2. # of collisions per second (z)
3. fraction of collisions w/ correct orientation (p)
(A=pz; k=Ae^-Ea/rt)
Activation energy - Correct Answer -the minimum amount of energy required to start a chemical
reaction, energy barrier
Maxwell-Boltzmann distribution - Correct Answer -Shows the spread of energies (distribution of
velocities) that molecules of gas or liquid have at a particular temperature
, What happens to maxwell-boltzmann distribution as temp increases? - Correct Answer -the distribution
of kinetic energies flattens and broadens and the position of the peak increases
Catalyst - Correct Answer -substance that speeds up the rate of a chemical reaction without being
consumed
homogenous catalyst - Correct Answer -a catalyst that is in the same phase as all the reactants and
products in a reaction system
heterogenous catalyst - Correct Answer -a catalyst that exists in a different physical state than the
reaction it catalyzes
Enzyme - Correct Answer -biological catalyst, specific protein
How do catalysts speed up reactions? - Correct Answer -by lowering the activation energy
SN1 mechanism - Correct Answer -2 step, slow unimolecular(1st order) 1st step, dissociative
SN2 mechanism - Correct Answer -1 step, bimolecular (2nd order) process, associative
Entropy - Correct Answer -(S) a measure of the distribution of energy in a system at a specific temp
2nd law of thermodynamics - Correct Answer -the total S of the universe increases in an spontaneous
process
Microstate - Correct Answer -(omega) a unique distribution of particles among energy levels
Standard molar entropies - Correct Answer -a measure of the energy dispersed into one mole of a
substance at a particular temperature
Answers
1st order rate law - Correct Answer -Rate = k[A]; linear
2nd order rate law - Correct Answer -rate = k[A]^2; nonlinear
1st order half life - Correct Answer -time required for 1/2 of reactant to react
radioactive decay - Correct Answer -The breakdown of a radioactive element, releasing particles and
energy
well known 1st order process; radioactive isotopes characterized according to half life (carbon dating)
collision model - Correct Answer -a model based on the idea that molecules must collide to react; used
to account for the observed characteristics of reaction rates
only certain orientations lead to reactions
What does k depend on in the Arrhenius Equation? - Correct Answer -1. fraction of molecules w/ Ea or
greater
-Maxwell-boltzmann distribution
2. # of collisions per second (z)
3. fraction of collisions w/ correct orientation (p)
(A=pz; k=Ae^-Ea/rt)
Activation energy - Correct Answer -the minimum amount of energy required to start a chemical
reaction, energy barrier
Maxwell-Boltzmann distribution - Correct Answer -Shows the spread of energies (distribution of
velocities) that molecules of gas or liquid have at a particular temperature
, What happens to maxwell-boltzmann distribution as temp increases? - Correct Answer -the distribution
of kinetic energies flattens and broadens and the position of the peak increases
Catalyst - Correct Answer -substance that speeds up the rate of a chemical reaction without being
consumed
homogenous catalyst - Correct Answer -a catalyst that is in the same phase as all the reactants and
products in a reaction system
heterogenous catalyst - Correct Answer -a catalyst that exists in a different physical state than the
reaction it catalyzes
Enzyme - Correct Answer -biological catalyst, specific protein
How do catalysts speed up reactions? - Correct Answer -by lowering the activation energy
SN1 mechanism - Correct Answer -2 step, slow unimolecular(1st order) 1st step, dissociative
SN2 mechanism - Correct Answer -1 step, bimolecular (2nd order) process, associative
Entropy - Correct Answer -(S) a measure of the distribution of energy in a system at a specific temp
2nd law of thermodynamics - Correct Answer -the total S of the universe increases in an spontaneous
process
Microstate - Correct Answer -(omega) a unique distribution of particles among energy levels
Standard molar entropies - Correct Answer -a measure of the energy dispersed into one mole of a
substance at a particular temperature
