CaCl₂(s) → Ca²⁺(aq) + 2Cl⁻(aq) ∆H = -81.5 kJ/mol A 15.0-g sample of CaCl₂ is dissolved in 105 g water with both substances at 25.0°C. Calculate the final temperature of the solution assuming no heat loss to the surroundings and assuming the solution has a specific heat capacity of 4.18 J/°C･g.

The final temperature of the solution is 46.93°C

Explanation:

we have to calculate the heat produced.

where,

= enthalpy change = 81.5 kJ/mol

q = heat released = ?  

m = mass of CaCl_2 = 15.0 g

Molar mass of CaCl_2 = 110.98 g/mol

Now put all the given values in the above formula, we get:

calculate the final temperature of solution in the calorimeter.

where,

q = heat produced = 11.0 kJ = 11000 J

m = mass of solution = 15.0 + 105 = 120.0 g

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

= initial temperature = 25.0°C

= final temperature = ?

Now put all the given values in the above formula, we get:

The final temperature of the solution is 46.93°C