Imagine you were doing a calorimetry experiment to measure the molar enthalpy change for dissolving ammonium chloride (NH4Cl(s)) in water, H2O(l) to create an aqueous NH4Cl (aq) solution.

What would you need to measure in order to calculate the molar enthalpy in kJ/mol?

Explain if the coffee cup calorimeter is an open, closed or isolated system.

How is the 1st Law of Thermodynamics applied when we do calculations with the coffee cup calorimeter? What assumptions do you make?

If the theoretical molar enthalpy of solution for NH4Cl(aq) is +14.7 KJ/mol, what mass of NH4Cl is needed to decrease the temperature of 100.0g of water by -20.0oC?

Write a thermochemical equation for this process, including the energy term.

What would be the molar enthalpy for the reaction used to produce ammonium chloride, as shown below? Use the enthalpies of formation (on the last page) to find this.

NH3(g) + HCl(g)→ NH4Cl(s) .