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1. A sample consists of 4 molecules with a total energy E-58. Each molecule can

ID: 2304294 • Letter: 1

Question

1. A sample consists of 4 molecules with a total energy E-58. Each molecule can occupy any one of a set of evenly spaced energy levels: 0, E, 28, 38, 48, 58 a. Identify how many different ways the total energy E-5? can be distributed among these molecules: ie. identify all these different "distributions" by describing how many particles, Nj are in the jth energy level with energy je. (Hint: there should be a total of 6 distinct "distributions" - label them as Di, D2, ..D b. For each of the distributions, calculate the number of possible microstates W c. For the "distribution" that has 3 molecules each with an energy , draw diagrams to show all the possible ways (there are W of them) that distribution can be achieved.

Explanation / Answer

a)

Energy levels

D1

D2

D3

D4

D5

D6

5?

O

4?

O

3?

O

O

2?

O

OO

O

?

O

OO

O

OOO

0

OOO

OO

OO

O

O

W


4


12


12


12


12


4

b)
General formula to calculate the number of microstates = N! / (n1! x n2!...)
Where N is the total number of particles. Here N = 4
n1, n2 ... are the number of particles in each state.

Total number of microstates for D1, W1 = 4!/(3! x 1!) = 4
For D2, W2 = 4!/(2! x 1! x 1!) = 4 x 3 = 12
For D3, W3 = 4!/(2! x 1! x 1!) = 4 x 3 = 12
For D4, W4 = 4!/(2! x 1! x 1!) = 4 x 3 = 12
For D5, W5 = 4!/(2! x 1! x 1!) = 4 x 3 = 12
For D6, W6 = 4!/(3! x 1!) = 4

c)
Consider that each molecules are a, b, c and d.

Energy levels

D6
(i)

D6
(ii)

D6
(iii)

D6
(iv)

5?

4?

3?

2?

d

c

b

a

?

abc

abd

acd

bcd

0

Energy levels

D1

D2

D3

D4

D5

D6

5?

O

4?

O

3?

O

O

2?

O

OO

O

?

O

OO

O

OOO

0

OOO

OO

OO

O

O

W


4


12


12


12


12


4