A2 Rate Of Reaction

Question 1

Rate of reaction

Answer 1

Change in amount or come net ration of a reactant or product per unit time

Question 2

4 factors affecting rate of reaction

Answer 2

1)temperature
2)surface area
3)pressure
4)catalyst
5)concentration

Question 3

Rate of reaction equation

Answer 3

Amount of reactant used up or amount of product formed /time taken
The change in concentration of reactants or products over time

Question 4

what does rate depend on

Answer 4

rate is dependent upon the concentration of all the reactant species
each reactant doesnt have the same contribution to rate

Question 5

the rate expression

Answer 5

the rate expression describes how the rate of reaction at a given temprature depends on the cocnetration of the species involved
a catalyst doesnt appear in the equation

Question 6

a+b=c if we change a conc there ar three posisble outcomes

Answer 6

a= no effect
a=has an effect eg. double a double rate
a=double a quadruple rate

Question 7

a has no effect

Answer 7

rate directly proportional [a]0
(1) no effect
change a for a constant
rate = k[a]0
0 order

Question 8

double a double rate

Answer 8

rate directly proporitonal [a]1
rate= k[a]1
1st order

Question 9

double a qudruple rate

Answer 9

rate direclty proportional [a]2
rate=k[a]2
2nd order

Question 10

overall rate equation

Answer 10

rate=k[A]^m[B]^n

k=rate contant the bigger it is the faster the reaction it increases with temperature

A=increases with temp
B=Increases with temp
m+n=order of reaction

Question 11

co efficents in rate equation

Answer 11

no revelence in rate expression only in chem equation
catalysts which arent in the chemical equation may appear in ate expression

Question 12

calculating untis for the rate constant- 0 order

Answer 12

units for k very depending on the overall order of the reaction
rate=k
units for rate are mol dm-3s-1
so units for k are mol dm-3s-1

Question 13

first order units

Answer 13

rate=k[a]
k=rate/[a]
s-1

Question 14

second order

Answer 14

rate=k[a][b]
k=rate/[a][b]
units= mol-1dm3s-1

Question 15

third order

Answer 15

rate=k[a][b]2
k=rate/[a][b]2
units = mol-2dm6s-1

Question 16

the initial rate method

Answer 16

-experiments conducted at constant temperature
-each with a different concentrations of reactants and catalysts
-concentration of one reactant vs time graph drawn
-tangent drawn at t=o , gradient is the initial rate
- at the initial rate the concnetration of all the substances are known exactly at this time
-compare the intial rates for pairs of experiments to find order with respect to each reactant

Question 17

effect of temperature

Answer 17

-small changes in temp gives large change in rate
-rough rule- for ever 10k increases rate doubles
-rate=k{a}{b}
concnetration doesnt change with temp only k increases with temp

Question 18

arrhenius equation

Answer 18

how temp affects k
k=Ae^-Ea/RT

Question 19

e

Answer 19

natural log constant

Question 19

K

Answer 19

rate constant

Question 20

A

Answer 20

pre exponential frequency factor
takes into account the frequency of collisions with the correct orientation
A has the same units as K

represents the proportion of molecules that exceed Ea

Question 21

-Ea

Answer 21

activation energy
if this increases k decreases and then rate decreases

Question 22

R

Answer 22

gas constant

Question 23

T

Answer 23

temperature
as temperature increases k increases so rate increases

Question 24

inverse of arrhenius equation

Answer 24

K= -Ea/RT + ln A
y= m x+ c