Kinetics

Question 1

Define ‘rate of reaction’ (rA)

A –> B

Answer 1

The number of moles of A reacting (disappearing) per unit volume per unit time. (mol/m3 s)

Question 2

How do you calculate the rate of appearance of B for the following irreverible reaction?
2A –> B

Answer 2

rB = vB/vA x rA
rB = 1/2 rA

Question 3

Derive a rate expression for the following non-gaseous reaction.
2A –> 3B

Answer 3

rA = kC X CA^n

Question 4

Derive a rate expression for the following gaseous reaction.

2A –> 3B

Answer 4

rA = kP x PA^n

Question 5

What does it mean if a reaction has 0 order?What are the units for kC in this case?

Answer 5

The rate of reaction is independent of the concentration of the reactants. mol/m^3 s

Question 6

What does it mean if a reaction is 1st order? What are the units for kC in this case?

Answer 6

The rate of reaction is dependent on the concentration of one reactant. 1/s

Question 7

What are the units for a second order reaction?

Answer 7

m^3/mol s

Question 8

Assuming the ideal gas law applies, how does kC relate to kP?

Answer 8

kC =kP(RT)^n

Question 9

Describe a system at equilibrium.

Answer 9

System is in a dynamic state where forward & backward reaction occurs at the same rate.

Question 10

How do you calculate the net rate of disappearance of A for a reversible reaction?
A B

Answer 10

rA = rA1 - rA-1

Question 11

For a reversible reaction at equilibrium, how do you define the equilibrium constant?
A B

Answer 11

K = k1/k-1 = CB/CA

Question 12

Define a general mole balance for a reactor system at equilibrium

Answer 12

Acc = moles in - moles out - moles reacted
0 = nA0 - nA - rA V

Question 13

Does a reversible reaction depend on concentration alone?

Answer 13

No.