Question

In a coffee-cup calorimeter, 1.70 g of NH4NO3 is mixed with 76.0 g of water at an initial temperature of 25.00°C. After dissolution of the salt, the final temperature of the calorimeter contents is 23.71°C. Assuming the solution has a heat capacity of 4.18 J/°C · g and assuming no heat loss to the calorimeter, calculate the enthalpy change for the dissolution of NH4NO3 in units of kJ/mol.

Answer 1

heat lost = mass H2O x specific heat H2O x (Tfinal-Tinitial) = q
delta H NH4NO3 = q/1.70 for delta H/g. Multiply by molar mass NH4NO3 to convert to delta H/mol. Convert from J to kJ.