Energetics, Kinetics & Thermodynamics

Question 1

What, other than the energy of the molecules, determines if a collision is successful?

Answer 1

Collision geometry

Question 2

What does the Maxwell-Boltzman curve look like?

Answer 2

Question 3

What does the area under the curve on a Maxwell-Boltzmann curve represent?

Answer 3

Total number of particles.

Question 4

What are effects of:

1. Temperature
2. Concetration
3. Catalyst on the Maxwell-Boltzmann curve?

Answer 4

1. Peak lower and displaced to the right
2. Curve displaced upwards (still goes through origin)
3. Curve doesn’t change but the activation energy decreases (shifts to left)

Question 5

How can the rate determining step be identified?

Answer 5

• The slowest step
• The step that appears in the rate equation

Question 6

What do the graphs look like for 0, 1st and 2nd order reactions?

[x=log(volume), y=log(1/t)]

Answer 6

Question 7

How does the rate constant (k) vary with temperature?

Answer 7

Question 8

What is psuedo zero order?

Answer 8

When the concentration of on reactant is so high that increasing it has no observable effect on the rate

Question 9

Why are 3^rd and 4^th order reactions almost exclusively multistep reactions?

Answer 9

It is unlikely that 3/4 particles will all collide at the same time with sufficient energy and in the correct orientation

Question 10

When is a reaction feasible/spontaneous?

Answer 10

Question 11

Even if a reaction is thermodynamically spontaneous, why might the rate of reaction be slow?

Answer 11

High activation energy