Question

In a coffee-cup calorimeter experiment, 10.00 g of a soluble ionic compound was added to the calorimeter containing 75.0 g h2o initially at 23.2°c. the final temperature of the solution was 31.8°c. what was the change in enthalpy for the dissolution of this compound? give your answer in units of joules per gram of compound. assume that the specific heat of the solution is the same as that of pure water, 4.18 j ⁄ g ⋅ °c.

Answer 1

The total heat gained by the solution is: q = mc(dT), where m = 75.0 g H2O, c = 4.18 J/g-C, and dT = 31.8 - 23.2 = 8.6 C. This gives a value of q = (75.0)(4.18)(8.6) = 2696.1 J.

If there were 10.00 g of the compound, then the heat of dissolution of the compound is: 2696.1 J / 10.00 g = 269.61 J/g.