Astudent added 5.350 g of ammonium chloride to 100.00 cm3 of water. the initial temperature of the water was 25.55℃ but it decreased to 21.79℃. calculate the enthalpy change that would occur when 1 mol of the solute is added to 1.0000 dm3 of water.

The enthalpy change that would occur when 1 mole of the solute is added to 1.0000 of water is 157.168 kJ/mol.

Explanation:

Amount of ammonium chloride added = 5.350 g

Moles of ammonium chloride =

Let heat absorbed by the 0.1 mole of solute be Q.and heat lost by water be Q'.

Q = -Q'

Volume of water,V =

Mass of water = m

Density of water ,d= 1 g/mL

Change in temperature of the water  =ΔT = 21.79°C- 25.55°C = -3.76°C

Specific heat capacity of water = c = 4.18J/g°C

Q= -Q'=-(-1571.68 J)=1571.68 J

0.1 mole of solute absorbed 1571.68 Joules of heat from of water .

When 1 mole of solute is dissolved in of water :

15716.8 Joule of heat is absorbed when 1 mole of solute is dissolved in of water

Heat absorbed when 1 mole of solute is dissolved in of water :

The enthalpy change that would occur when 1 mole of the solute is added to 1.0000 of water is 157.168 kJ/mol.