(Solved): 2. b. When a solid dissolves in water heat evolved or absorbed, known as the heat of dissolution, c ...

2. b. When a solid dissolves in water heat evolved or absorbed, known as the heat of dissolution, can be determined using a coffee cup calorimeter. A general chemistry student finds that when $2.597\mathrm{g}$ of anhydrous cobalt chloride (molar mass: 129.839 $\mathrm{g}/\mathrm{mol}$ ) is dissolved in $125.00\mathrm{mL}$ of water, the temperature of the solution increases from $24.50^{\circ }\mathrm{C}$ to $27.75^{\circ }\mathrm{C}$. The calorimeter constant (the heat capacity of calorimeter) was determined, in a separate experiment, to be $1.70\mathrm{J}/{}^{\circ }\mathrm{C}$. Assume that - the density of the solution is $1.02\mathrm{g}/\mathrm{mL}$; the specific heat of the solution is equal to the specific heat of water $=4.18\mathrm{J}/{}^{\circ }\mathrm{C}.\mathrm{g}$ Calculate the following: (i) Heat loss: (ii) Heat gain: (iii) enthalpy of dissolution of ${\mathrm{CoCl}}_2$ in $\mathrm{kJ}/\mathrm{mol}$.