Two salts are being considered for a single-use cold pack

CHEMISTRY · Subjective · A Level · Chemistry · Thermodynamics · Thermodynamics

Problem

Two salts are being considered for a single-use cold pack. •

\text{MgCl}_2

\Delta H_{lattice}=+2523\,\text{kJ mol}^{-1}

\Delta H_{hydration}=-2460\,\text{kJ mol}^{-1}

•

\text{NH}_4\text{NO}_3

\Delta H_{lattice}=+648\,\text{kJ mol}^{-1}

\Delta H_{hydration}=-630\,\text{kJ mol}^{-1}

Assuming no heat exchange with the surroundings, which salt will produce the larger magnitude of temperature change when

0.10\,\text{mol}

of the salt is dissolved in

100\,\text{g}

of water at

25\,\text{°C}

? Support your choice with a brief calculation of the enthalpy change (in kJ) for the amount dissolved.