Chapter U3.17, Problem 8E

Interpretation Introduction

Interpretation: Whether the pressure of He and O₂ gas will be same or different needs to be determined if number of moles of both gases is 1 mol, volume is 22.4 L and temperature is 273 K.

Concept Introduction: The ideal gas equation is represented as follows:

  $PV=nRT$

Here, P is pressure, V is volume, n is number of moles and T is temperature of the gas.

R is Universal gas constant with value $0.082\text{ L atm/K mol}$ .

Answer to Problem 8E

Both He and oxygen gas have same pressure.

Explanation of Solution

The ideal gas equation is represented as follows:

  $PV=nRT$

On rearranging,

  $P=\frac{nRT}{V}$

Here, pressure is calculated using number of mol, volume and temperature which is same for both He and O₂ gas. Also, R is Universal gas constant which is same for all the gases. Therefore, for gases with same number of moles, volume and temperature, the pressure of the gas will be same.

The pressure can be calculated as follows:

  $P=\frac{\left(1\text{ mol}\right)\left(0.082\text{ L atm/K mol}\right)\left(273\text{ K}\right)}{\left(22.4\text{ L}\right)}=0.99\text{ atm}$

Conclusion

Thus, both helium and oxygen gas have same pressure that is 0.99 atm.