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

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

Step-by-step 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)=(3RT)/(2N_A)`

`E_(avg)=(3R* 288.15 K)/(2N_A)`

`E_(avg)=(3* 8.314 J /mol K* 288.15 K)/(2* 6.022* 10^(23))=5.967* 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)=(3RT')/(2N_A)`

`E'_(avg)=(3R* 215 K)/(2N_A)`

`E'_(avg)=(3* 8.314 J /mol K* 215 K)/(2* 6.022* 10^(23))=4.452* 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.