Rate equation

Question 1

rate of reaction

Answer 1

change in the concentration of reactants or products per unit time

Question 2

unit of rate

Answer 2

moldm-3s-1

Question 3

why does doubling the temperature have a greater affect on rate than doubling [A]

Answer 3

Reaction occurs when molecules have E ≥ Ea
Doubling temperature makes many more particles have this E
Doubling [A] only doubles the number of particles with this E

Question 4

rate equation

Answer 4

Rate = k[A]m[B]n

Question 5

what is m and n

Answer 5

the orders with respect to reactants A and B = 0, 1, and 2

Question 6

what is k

what can it be affected by

Answer 6

rate constant (can only be changed by a change in temperature: ↑T = ↑k)

Question 7

order of reaction

Answer 7

order of reaction with respect to a reactant is the power of the concentration of a particular species in the rate equation

Question 8

overall order

Answer 8

= m + n

Question 9

zero order

Answer 9

[A]0, so if [A] doubles = rate remains constant

Question 10

first order

Answer 10

[A]1, so if [A] doubles = rate doubles

Question 11

second order

Answer 11

[A]2, so if [A] doubles = rate quadruples

Question 12

rate determining step (3)

Answer 12

same proportion of species involved in or before the rate-determining step also appear in the rate equation

components which appear after the RDS do not appear in the rate equation

slowest step which controls the overall rate of reaction

Question 13

Arrhenius equation

Answer 13

k=Ae^(-Ea/RT)

k: rate constant
A: Arrhenius constant 
e: 2.71
Ea: activation energy J/mol
R: gas constant 8.31

Question 14

log Arrhenius equation

Answer 14

lnk = -Ea/RT + lnA

Question 15

which equation is used to find Ea
Axis on the graph
what does the y intercept mean
what does the gradient mean

Answer 15

lnk = -Ea/R x 1/T + lnA

y axis = lnk or ln(rate)
gradient m = -Ea/R
x axis = 1/T
y intercept c = lnA

Question 16

rearranged Arrhenius equation for Ea

Answer 16

Ea=RT(lnA-lnk )

Question 17

which equation is used to find rate order
axis on the graph
what does y intercept mean
what does the gradient mean

Answer 17

rate = k[A]n
log(rate) = n log[A] + log(k)

y axis = log(rate)
gradient m = rate order n
x axis = log [A]
y intercept c = log(k)

Question 18

partial pressure

Answer 18

pressure that a gas in a mixture would have if it alone occupied the volume occupied by the whole mixture

Question 19

what is Kp only affected by

Answer 19

Kp is only affected by temperature: e , Kp↑

Question 20

Kp equation

Answer 20

K_p= (p(C)^r p(D)^s)/(p(A)^p p(B)^(q ) )= (pressure of products)/( pressure of reactants)

Question 21

mole fraction equation

Answer 21

mole fraction= (number of equilibrium moles of gas A)/(total number of equilibrium moles)

Question 22

partial pressure of gas A equation

Answer 22

partial pressure of gas=mole fraction of gas A x total pressure