5.1.1 How Fast

Question 1

Half life definition

Answer 1

time taken for half of a reactant to be used up

Question 2

what type of half life do first order reactions have

Answer 2

constant
concentration halves every half life

Question 3

exponential decay

Answer 3

1st order relationship can be confirmed by concentration time graph measuring successive half lives

Question 4

how to work out order from half life

Answer 4

measure several half lives
check if they’re constant
zero/ second order are not constant

Question 5

rate equation using graph

Answer 5

= K [position of tangent]

Question 6

what is the rate determining step

Answer 6

slowest step

Question 7

Arrhenius equation

Answer 7

K = A x e^-(Ea/RT)

Question 8

what does the A stand for in the arrhenius equation

Answer 8

frequency factor
constant that represents number of collisions per second with correct orientation to react

Question 9

y = mx + c for arrhenius equation

Answer 9

lnk = (-Ea/R)(1/T) + lnA

Question 10

what graph does a zero order create

Answer 10

straight line with negative gradient

Question 11

what graph does first order create

Answer 11

downward curve with decreasing gradient overtime

Question 12

what graph does second order create

Answer 12

downward curve, steeper at start but tails off more slowly

Question 13

zero order definition

Answer 13

when concentration has no effect on rate

Question 14

first order definition

Answer 14

conc and rate both doubled or both tripled

Question 15

second order definition

Answer 15

conc doubled rate is quadrupled

Question 16

overall order

Answer 16

sum of all orders
m+n

Question 17

methods of contiuous monitoring of rate

Answer 17

gas collection
mass loss
colour change by eye or colorimeter

Question 18

what happens to half life if you double the concentration

Answer 18

No change

Question 19

what happens to rate constant if you increase temperature

Answer 19

rate increases so value of K also increases

Question 20

what happens to K if increase temp by 10

Answer 20

doubles

Question 21

what must be in reaction mechanism for it to be valid

Answer 21

reactant in RDS must be consistant with rate equation
sum of all steps must give overall reaction equation