Question

You have two flasks of equal volume. Flask A contains H2 at 0 °C and 1 atm pressure. Flask B contains CO2 gas at 25 °C and 2 atm pressure. Compare these two gases with respect to each of the following: (a) average kinetic energy per molecule (b) root mean square speed (c) number of molecules(d) mass of gas

Answer 1

Answer:

(a) CO2 will have more average kinetic energy per molecule.

(b) The root mean square speed for H2 is greater than CO2.

(c) The number of molecules will remain the same in each case.

(d) The density of CO2 will be greater than the density of H2.

Explanation:

(a) The formula of Average Kinetic Energy is:

$K=\frac{3}{2}*\frac{R}{n_{moles}}*T$

In this case, the higher the temperature, the higher the energy, so CO2 will have more average kinetic energy per molecule.

(b) The formula of Root mean square speed:

$v=\sqrt{\frac{3*R*T}{M}}$

Replacing the values of constant gases (R), temperature (T) and molar mass (kg/mol) for each compound, we can calculate the root mean square speed.

The root mean square speed for H2 is 2,609.4m2/s2 and for CO2 is 410.96m2/s2.

(c) The number of molecules will remain the same in each case since the volume is constant.

(d) Using the formula of density (density=mass/volume), and knowing that the volume remains the same, the density of CO2 will be greater than the density of H2 since the pressure is higher in the flask of CO2.