8. Thermochemistry
Heat Capacity
8. Thermochemistry Heat Capacity
36PRACTICE PROBLEM
Instant cold packs are used to ice athletic injuries on the field by separating a thin plastic divider. It contains ammonium nitrate and water. When the divider is broken, the ammonium nitrate dissolves according to the endothermic reaction:
NH4NO3(s) → NH4+(aq) + NO3-(aq)
In the reaction, 2.55 g of NH4NO3 is dissolved in enough water to make 59.0 mL of solution. The initial temperature is 30.8 °C and the final temperature is 24.9 °C. Calculate the change in enthalpy for the reaction in kJ. (Use 1.0 g/mL as the density of the solution and 4.18 J/g°C as the specific heat capacity.)
Instant cold packs are used to ice athletic injuries on the field by separating a thin plastic divider. It contains ammonium nitrate and water. When the divider is broken, the ammonium nitrate dissolves according to the endothermic reaction:
NH4NO3(s) → NH4+(aq) + NO3-(aq)
In the reaction, 2.55 g of NH4NO3 is dissolved in enough water to make 59.0 mL of solution. The initial temperature is 30.8 °C and the final temperature is 24.9 °C. Calculate the change in enthalpy for the reaction in kJ. (Use 1.0 g/mL as the density of the solution and 4.18 J/g°C as the specific heat capacity.)