Answer:
Explanation:
The average kinetic energy of gas particles depends only on the temperature. Thus you must expect that the average kinetic energies of both helium gas and methane gas at 25ºC are equal.
1. Kinetic energy of helium molecules
The mass of 1 mole of molecules of helium is 4 grams. Convert to kg, to use SI units: 0.004 kg
Convert the velocity to m/s: 1.26×10⁵ cm/s = 1.26 × 10³ m/s
[tex]KE=\dfrac{1}{2}mv^2=\dfrac{1}{2}(0.004kg/mol)(1.26\times 10^3m/s)=3.18\times 10^3J/mol[/tex]
2. Kinetic energy of methane molecules
The mass of 1 mole of molecules of methade is 416 grams. Convert to kg, to use SI units: 0.016 kg
Convert the velocity to m/s: 6.30×10⁴ cm/s = 6.30 × 10⁴ m/s
[tex]KE=\dfrac{1}{2}mv^2=\dfrac{1}{2}(0.016kg/mol)(6.30\times 10^2m/s)=3.18\times 10^3J/mol[/tex]
As expected both average kinetic energies are the same.
