1. Determination of the Heat Solution
Experiment (3)
Determination of the Heat Solution

2. Theory Heat of Solution
The amount of heat absorbed or evolved when a definite weight of solute dissolved in a definite weight or volume of solvent to produce a solution of definite concentration.

3. Procedure Weight dry calorimeter (W1).
Measure 150 ml of water by using measuring cylinder and transfer it into the calorimeter and re-weights the calorimeter and its contents (W2).
Measure the temperature of water in the calorimeter (Ti).
Weight 3g of NH4Cl, introduce it in the calorimeter then cover it and stir the content about 15 min until complete dissolution.
Read the temperature until the temperature become constant (Tf).
Repeat the above steps using 6,9 and 12g of NH4Cl with the same 150 ml water.

4. Procedure Calculate the heat of solution in each case.
Plot a graph between the heat of solution and the concentration (mole/l).
Calculate the heat of the solution at infinite dilution by extrapolation to zero concentration.

5. Results W1 = Weight of the system (Dry Calorimeter).
W2 = Weight of the system (Calorimeter) + H2O.
Ti = Initial temperature.
Tf = Final temperature of solution after dissolution.

6. Results W3 = W2 – W1 (H2O) W4 (NH4Cl) W5 = W3 + W4 Ti Tf ΔT
qcalorimeter
qsolution
qheat of solution M
3 g
6 g
9 g
12 g

7. Calculations qsystem = qcalorimeter + qs + qheat of solution
The system is isolated => qsystem = 0
qheat of solution = - ( qcalorimeter + qs )
qs = S NH4Cl × W5 × ΔT
= 0.95 × (W3 + W4) × (Tf – Ti)
qcalorimeter = Ccalorimeter × ΔTcalorimeter

8. Calculations
𝑀= 𝑊 𝑁𝐻 4 𝐶𝑙 × 1000 𝑀 𝑤𝑡 × 𝑉(𝑚𝑙) * V = 150 ml.