What is the change in temperature when 3.00 grams of calcium chloride is dissolved in 100 mL of water?

5.19

oC

Given the change in the temperature from adding 3.00 grams of calcium chloride to 100.00 mL of water (5.19), calculate the enthalpy of solution for calcium chloride in units of kJ/mol.

kJ/mol

82.74 kJ/mol

Explanation:

Mass of Water = 100 mL = = 100 g

Mass of CaCl₂ = 3 g

Total solution mass = H₂O mass + CaCl₂ mass = 103 g

Heat capacity is same as that of water 4.184 J/g °C

∴ Heat released on dissolution = Mass x Specific heat x ΔTemperature

= 103 g x 4.184 J/g °C x 5.19 °C

= 2236.64 J

Molar mass of CaCl₂ = 110.98 g/mol

∴ Heat released on dissolution of a mol of CaCl₂

= (2236.64 J / 3.0 g) x 110.98 g/mol

= 82740.769 J/mol

In KiloJoules = 82.74 kJ/mol