What is the enthalpy change (in kJ) of a chemical reaction that raises the temperature of 250.0 mL of solution having a density of 1.25 g by 10.2 °C? (The specific heat of the solution is 3.733 J .)

Question

What is the enthalpy change (in kJ) of a chemical reaction that raises the temperature of 250.0 mL of solution having a density of 1.25 g  by 10.2 °C? (The specific heat of the solution is 3.733 J   .)

Quizplus · Accepted Answer

First, we need to find the mass of the solution:
density = mass/volume
1.25 g/mL = mass/250.0 mL
mass = 312.5 g

Next, we can use the equation:
q = mcΔT
where q is the heat transferred, m is the mass of the solution, c is the specific heat, and ΔT is the change in temperature.

We need to convert mL to L and J to kJ:
q = (312.5 g) (3.733 J/g°C) (10.2°C) / 1000 = -11.9 kJ

The enthalpy change is equal in magnitude but opposite in sign to the heat transferred, so the enthalpy change is:
ΔH = -q = 11.9 kJ (rounded to 2 significant figures)

Therefore, the correct answer is D) -11.9 kJ.

What Is the Enthalpy Change (In KJ) of a Chemical