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 change in enthalpy for the dissolution of the ionic compound is 269.19 J/g, indicating an exothermic reaction where the temperature increased from 23.2°C to 31.8°C.

Step-by-step explanation:

To find the change in enthalpy for the dissolution of the soluble ionic compound, we can use the formula q = m × c × ΔT, where q is the heat absorbed or released, m is the mass of water plus the mass of the solute, c is the specific heat capacity, and ΔT is the change in temperature.

First, calculate the change in temperature: ΔT = 31.8°C - 23.2°C = 8.6°C.

Next, calculate the total heat change using the mass of water, as the mass of the compound is negligible in comparison: q = (75.0 g × 4.18 J/g°C × 8.6°C) = 2691.9 J.

Then, convert the heat change to joules per gram of compound: 2691.9 J / 10.00 g = 269.19 J/g.

The reaction is exothermic since the temperature increased, indicating that heat was released during the dissolution of the ionic compound into the water.