Apparatus

1. Thermometer to measure initial and final temperature
2. Insulated container(plastic/Styrofoam) to prevent heat loss or gain during reaction
3. Electronic balance(weigh mass of reactant)
4. Measuring cylinders to measure volume of solvent
5. The solute should be properly dissolved and the heat should be evenly distributed throughout the solution as best as possible. Hence a stirring rod should be used

Assumption

1. 1ml of water or aqueous solution is equal to 1 gram
2. Specific heat capacity of a dilute solution is the same as water=4.2J/g/K
3. Specific heat capacity of a container is negligible
4. It is also assumed that no heat is lost or gained to or from the solution

H=M Δ θ C,

Where m is the mass of the solvent, C is the specific heat capacity of water or dilute solution and  Δθ is the change in temperature.