437,338 views
33 votes
33 votes
Using a Boltzmann distribution, find the fraction of atoms in the excited state versus the ground state (i.e. the relative population) in a plasma source and a flame source. Assume that the lowest energy of a sodium atom lies at 3.371x10-19 J above the ground state, the degeneracy of the excited state is 2, whereas that of the ground state is 1, and the temperature of the flame is 3000 K and 10,000 K for plasma.

User Evgeniy Kuzmin
by
2.5k points

2 Answers

24 votes
24 votes

Final answer:

The relative population of sodium atoms in excited vs ground state can be found using the Boltzmann distribution, which involves the energy difference between states and the temperature. By inputting the given energy levels, degeneracies, and temperatures for the flame (3000 K) and plasma (10,000 K), we can calculate the ratios of populations for each source.

Step-by-step explanation:

The relative population of sodium atoms in the excited state compared to the ground state can be determined using the Boltzmann distribution. The Boltzmann distribution relates the probability of an atom being in a particular energy state at a given temperature. The probability P(n) of an atom being in the energy level n is given by:

P(n) = Ce-εn/kT

where C is a normalization constant, εn is the energy of level n, k is Boltzmann's constant, and T is the temperature in kelvins. Since we're interested in the relative population between the excited state (n=1) and ground state (n=0), we can set the ratio:

P(1)/P(0) = (g₁/g₀)e-(E₁-E₀)/kT

where g₀ and g₁ are the degeneracies of the ground and first excited states, respectively, and E₁-E₀ is the energy difference between these states. Given that E₀ = 3.371x10-19 J, g₀ = 1, g₁ = 2, and the temperatures for our flame and plasma sources are 3000 K and 10,000 K respectively, the relative populations can be calculated for each source.

For example, for the flame source at 3000 K:

P(1)/P(0) = (2/1)e-(3.371x10-19)/(1.38x10-23x3000)

This calculation can be repeated for the plasma source at 10,000 K to find the relative populations in that case.

User Swapnil Sonawane
by
3.1k points
5 votes
5 votes

Answer:

0.174 plasma


image flame

Step-by-step explanation:

Given :

Energy :


image J per atom


image (degenraci of excited state)

g = 1 (degenraci of excited state)

Boltzmann Distribution


image

where,


image = atoms in excited state

N = atoms in lower energy level

k =
image J/K

Therefore,

Relative population in plasma

T = 10,000 K


image


image


image


image


image

Relative population in flame

T = 3000


image


image


image


image


image

User Schematic
by
2.4k points