Question

Which of the following would have the highest average kinetic energy?

Cl2 gas at 35 °C

F2 gas at 15 °C

O2 gas at 25 °C

N2 gas at 50 °C

Answer 1

N₂ gas at 50 °C.

Step-by-step explanation:

• From the postulates of the kinetic theory of gases; all gases at a given temperature have the same average kinetic energy.

• The average kinetic energy of gases can be calculated from the relation: K =
  `(3 R)/(2NA)` T.

Where, K is the average kinetic energy (measured in Joule),

R is the general gas constant (R = 8.314 J/mol.K)

NA is Avogadros number (6.023 x 10²³ atoms/mol)

T is the temperature (measured in Kelvin).

• It is clear from the relation that K depends only on the temperature.

• So, N₂ gas at 50 °C has the highest average kinetic energy since it is at the higher temperature than other gases.