When of (molar mass ) dissolves in of water inside a calorimeter with

CHEMISTRY · Single correct · A Level · Chemistry · Energetics · Energetics

Problem

When

3.50\,\text{g}

\mathrm{NH_4NO_3}

(molar mass

80.0\,\text{g}\,\text{mol}^{-1}

) dissolves in

50.0\,\text{g}

of water inside a calorimeter with

C_{\text{cal}} = 28.5\,\text{J}\,^\circ\!\text{C}^{-1}

, the temperature of the mixture decreases by

2.9\,^\circ\!\text{C}

. What is the enthalpy of dissolution per mole of

\mathrm{NH_4NO_3}

? (a)

+12\,\text{kJ}\,\text{mol}^{-1}

(b)

-17\,\text{kJ}\,\text{mol}^{-1}

(c)

+17\,\text{kJ}\,\text{mol}^{-1}

(d)

+23\,\text{kJ}\,\text{mol}^{-1}