What is the average kinetic energy of a molecule of oxygen at a temperature of 300 k?

We have: Average Kinetic Energy(E) = 3/2 kT
Here, k (Boltzmann constant) = 1.38 × 10⁻²³
T (Temperature) = 300 K

Substitute their values into the expression:
E = 3/2 × 1.38 × 10⁻²³ × 300
E = 6.21 × 10⁻²¹ J

Finally, correct answer would be 6.21 × 10⁻²¹ J

Hope this helps!