Question

The $C_p$ of an ideal gas is $10.314 \text{ J} \text{mol}^{-1} \text{K}^{-1}$. One mole of this gas is expanded against a constant pressure of $p \text{ atm}$. The change in temperature during expansion is $1.0 \text{ K}$. The values of $q$ (in J) and $\Delta H$ (in $\text{J} \text{mol}^{-1}$) are respectively

• A. $10.314, 10.314$
• B. $2.000, 10.314$
• C. $10.314, 2.000$
• D. $2.000, 2.000$

Hint:

In thermodynamics, for any process, the change in enthalpy is given by $\Delta H = n C_p \Delta T$. For an ideal gas, this is true regardless of whether the pressure is constant. However, the heat exchanged ($q$) is only equal to $\Delta H$ when the process is performed at constant pressure ($q_p = \Delta H$). Given the context of a competitive exam, the question intends for this equality to hold.

Answer 1

The Correct Option is A