3.15 mol of an unknown solid is placed into enough water to make 150.0 mL of solution. The solution's temperature increases by 11.81°C. Calculate ∆H, in kJ/mol, for the dissolution of the unknown solid. (The specific heat of the solution is 4.184 J/g･°C and the density of the solution is 1.20 g/mL).

for the reaction 2 Hg (l) + O2 (g) →2 HgO (s), ∆H = - 43 kcal/mol Does entropy increase or decrease in this process? Explain.

5.21 g of MgSO₄ is placed into 100.0 mL of water. The water's temperature increases by 6.70°C. Calculate ∆H, in kJ/mol, for the dissolution of MgSO₄. (The specific heat of water is 4.184 J/g･°C and the density of the water is 1.00 g/mL). You can assume that the specific heat of the solution is the same as that of water.

3.15 mol of an unknown solid is placed into enough water to make 150.0 mL of solution. The solution's temperature increases by 19.21°C. Calculate ∆H for the dissolution of the unknown solid. (The specific heat of the solution is 4.18 J/g･°C and the density of the solution is 1.20 g/mL). Make sure answer is in the correct number of significant figures.