Chemistry

Problem

When

2.00\,\text{g}

of solid

\mathrm{NaOH}

is dissolved in

100.0\,\text{g}

of water initially at

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

, the temperature of the solution rises to

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

. Assume the specific heat capacity of the solution is

4.18\,\text{J}\,\text{g}^{-1}\,^{\circ}\!\text{C}^{-1}

and the calorimeter absorbs negligible heat. What is the enthalpy change per mole,

\Delta H_{\text{solution}}

, for

\mathrm{NaOH(s)}

(in

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

)? a)

+62.7

-31.3

-62.7

-125