A rigid container initially holds of water vapor at 100 °C

CHEMISTRY · Single correct · AP · Chemistry · Thermochemistry · Thermochemistry

Problem

A rigid container initially holds

1.50\,\text{mol}

of water vapor at 100 °C. The system cools until

0.75\,\text{mol}

remain as vapor while the other

0.75\,\text{mol}

first condense at 100 °C and then freeze at 0 °C. Neglect heat capacities and use

\Delta H_{\text{vap}}=+40.7\,\text{kJ mol}^{-1}

(100 °C) and

\Delta H_{\text{fus}}=+6.01\,\text{kJ mol}^{-1}

(0 °C). What is the total heat released by the system during this process? (a)

+35\,\text{kJ}

(b)

-31\,\text{kJ}

(c)

-26\,\text{kJ}

(d)

-35\,\text{kJ}