Question

0.700 moles of an unknown solid is placed into water to make 150.0 ml of solution. The solution's temperature decreases by 10.01 °C. Calculate ΔH, 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 1.02 g/ml).

Answer 1

To calculate the ΔH, or enthalpy change, for the dissolution of the unknown solid, use the formula ΔH = q/n, where q is the heat transferred and n is the number of moles of the unknown solid. Calculate q using the formula q = mCΔT, where m is the mass of the solution, C is the specific heat of the solution, and ΔT is the change in temperature. Finally, divide q by the number of moles to find the ΔH in kJ/mol.

Step-by-step explanation:

To calculate the ΔH, or enthalpy change, for the dissolution of the unknown solid, we can use the formula ΔH = q/n, where q is the heat transferred and n is the number of moles of the unknown solid.

First, we need to calculate q, the heat transferred. We can use the formula q = mCΔT, where m is the mass of the solution, C is the specific heat of the solution, and ΔT is the change in temperature.

Using the given information, we can calculate q and then divide it by the number of moles of the unknown solid to find the ΔH in kJ/mol.