Question

A total of 2.00 mol of a compound is allowed to react with water in a foam coffee cup and the reaction produces 189 g of solution. the reaction caused the temperature of the solution to rise from 21.00 to 24.70 ∘c. what is the enthalpy of this reaction? assume that no heat is lost to the surroundings or to the coffee cup itself and that the specific heat of the solution is the same as that of pure water.

Answer 1

In order to determine the enthalpy change of the reaction, we first calculate the amount of energy that was liberated by the reaction. This is given by:

Q = mcΔT

For water, the specific heat capacity of water (c) is 4.184 Joules per gram

Q = 189 * 4.184 * (24.7 - 21)
Q = 2925.87 Joules

The enthalpy of a reaction is the energy change per mole of reactants, so the enthalpy change is:
2,925.87 / 2 = 1462.935

The enthalpy change of the reaction is -1462.94 Joules per mole.