Question

How does a sample of helium at 15 °C compare to a sample of helium at 215 K? The helium at 15 °C has a higher average kinetic energy than the sample at 215 K. The helium at 15 °C has lower nuclear energy than the sample at 215 K. The helium at 15 °C has slower-moving atoms than the sample at 215 K. The helium at 15 °C has smaller atoms than the sample at 215 K.

Answer 1

The answer is A: The helium at 15C has a higher average kinetic energy than the sample at 215 k.

Answer 2

Answer:

The correct answer is: 'The helium at 15 °C has a higher average kinetic energy than the sample at 215 K'.

Explanation:

Average kinetic energy of the helium atom at 15 °C .

Temperature of the gas = T = 15 °C = 288.15 K

Average kinetic energy is determined by formula:

$E_{avg}=\frac{3RT}{2N_A}$

$E_{avg}=\frac{3R\times 288.15 K}{2N_A}$

$E_{avg}=\frac{3\times 8.314 J /mol K\times 288.15 K}{2\times 6.022\times 10^{23}}=5.967\times 10^{-21} J$

Average kinetic energy of the helium atom at 215 K.

Temperature of the gas = T' = 215 K

Average kinetic energy is determined by formula:

$E'_{avg}=\frac{3RT'}{2N_A}$

$E'_{avg}=\frac{3R\times 215 K}{2N_A}$

$E'_{avg}=\frac{3\times 8.314 J /mol K\times 215 K}{2\times 6.022\times 10^{23}}=4.452\times 10^{-21} J$

$E_{avg}>E'_{avg}$

The helium at 15 °C has a higher average kinetic energy than the sample at 215 K.Hence, it is the correct option.