A

A. What is the identity of the metal cation: Ca 2+ , Sr 2+ , Ba 2+?B. (a)NH4NO3 (s) → NH4+ -

When a 4.25-g sample of solid ammonium nitrate dissolves in 60.0 g of water in a coffee-cup calorimeter, the temperature drops from 22.0? to 16.9?. Calculate ΔH (in kJ/mol NH4NO3 ) for the solution process

(aq) + NO3 (aq)

Assume that the specific heat of the solution is the same as that of pure water (4.184 J/g?). (b) Is this process endothermic or exothermic?

C. From the enthalpies of reaction

2 C (s) + O2 (g) → 2 CO (g) ΔH = -221.0 kJ

2 C (s) + O2 (g) + 4 H2 (g) → 2 CH3OH (g) ΔH = -402.4 kJ

calculate ΔH for the reaction CO (g) + 2 H2 (g) → CH3OH (g