Making a reaction go faster -part 2 9.1 3

Question 1

molecules in a sample of gas

Answer 1

have a wide range of energies.to estimate what fraction of collisions will have required activation energy need to know the energy distribution

Question 2

Maxwell-Boltzmann distribution curves

Answer 2

see fig a pg.256
important points
neither curve is symmetrical
both curves start at the origin and finish by approaching the x axsis asymptotically
the area under each curve is the same since the number of molecules has not changed
peak of t2 is displaced to the right and lower than t1
x=energy E
y=fraction of molecule with energy E

Question 3

fig b pg 256

Answer 3

see book

Question 4

how does an increase in temperature increase rate of reaction

Answer 4

increases the fraction of molecules that possess the required activation energy
the number of successful collisions per second increases

Question 5

draw a molecular energy curve instead of a collision distribution curve

Answer 5

assumes fraction of collisions with activation energy is equal to the fraction of molecules with this energy

Question 6

gas

Answer 6

molecules moving at high speed so frequently collide

Question 7

solution

Answer 7

more closely packed than gas .in low to medium concentrations most of the solution is solvent so solute molecules tend to be entirely surrounded by solvent molecules . these molecules are trapped in a “solvent cage”

Question 8

gas vs solution

Answer 8

a number of solute molecules may become trapped in a solvent cage this increases the collision rate

Question 9

Two stages to a reaction in solution

Answer 9

1. molecules have to come together by process of diffusion into the same solvent cage
2. they have to react

Question 10

for simple reactions involving two species

Answer 10

chance of them encountering each other in solution is proportional to their concentrations just like gas phase kinematics is the sane