chapter 13

Question 1

what are reaction rates? rate laws?

Answer 1

how we measure rates

how the rate depends on amount of reactants

Question 2

what are integrated rate laws?

Answer 2

How to calc amount left or time required for rxn.

Question 3

what is a half life?

Answer 3

How long it takes to react 50% of reactants.

Question 4

what is arrhenius equation?

Answer 4

rate constant vs T

Question 5

what are mechanisms and catalysts?

Answer 5

Rates vs molecular processes.

Speeding up processes

Question 6

what is kinetics?

Answer 6

the study of REACTION RATES and their relation to the way the reaction proceeds, i.e., its MECHANISM

Question 7

3 types of reactions

Answer 7

Not thermodynamically favored (reactant favored) 
Thermodynamically favored (product favored), but not kinetically favored (slow)
Thermodynamically favored (product favored) and kinetically favored (fast)

Question 8

thermodynamically favored vs kinetically

Answer 8

Thermodynamically favored (product favored) kinetically favored (fast)

Question 9

how does concentration of reactants affect reaction rates?

Answer 9

increase concentration of reactants

increases likelihood molecules will coll

Question 10

how does temperature affect reaction rates?

Answer 10

Higher temperatures, more kinetic energy, move faster, and collide more often withgreater energy

Question 11

how do catalysts affect reaction rates?

Answer 11

Speed rxn by changing mechanism

Question 12

what change is a reaction rate?

Answer 12

change in concentration of a reactant or product with time.

Question 13

3 kinds of reaction rates?

Answer 13

initial rate, average rate, and instantaneous rate

Question 14

what do we need to determine reaction rate? how is it measured?

Answer 14

To measure reaction rate, need concentration of either a reactant or product at several time intervals.
The concentrations are measured using titrations, spectroscopic method or pressure (for a gas) to name a few.

Question 15

definition of reaction rate

Answer 15

Reaction rate: changes in a concentration of a product or a reactant per unit time

Question 16

what can the reaction order be?

Answer 16

The exponents m, n,  
•	are the reaction order
•	can be 0, 1, 2 or fractions (negative?)
May include products and catalyst
•	must be determined by experiment!!!

Question 17

overall reaction order

Answer 17

sum of orders

Question 18

what happens as conc of zero order changes?

Answer 18

Reactant that is zero order

– no change in the rate with increasing concentration

Question 19

what happens as conc of first order changes?

Answer 19

any change in concentration identically changes rate increase concentration by 7.2 times
results in rate increase of 7.2 times

Question 20

what happens as conc of second order changes?

Answer 20

Reactant that is 2nd order
-rate of reaction changes as the square of the
change in concentration increase concentration by 7.2 times
results in rate increase of (7.2)2 = 52 times

Question 21

first order rate law + integrated rate law

Answer 21

• (D [A] / D time) = k [A]1

ln[A]t = ln[A]0 - kt

Question 22

fraction of reactant first order

Answer 22

[A] / [A]0 = fraction of reactant A remaining after time t has elapsed.

Question 23

how can we tell order on a graph?

Answer 23

All 1st order reactions have straight line plot for ln [A] vs. time with the slope = -k.
(k is always positive so slope is negative)