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/ml by 9.20°C? (The specific heat of the solution is 3.74 J/g ∙ K.)
A) -7.20 kJ
B) 12.7 kJ
C) 8.80 kJ
D) -10.8 kJ
E) 6.40 kJ

Question

Quizplus · Accepted Answer

The enthalpy change can be calculated using the formula q = mcΔT. First, calculate the mass: 250.0 mL * 1.25 g/mL = 312.5 g. Then, q = 312.5 g * 3.74 J/g∙K * 9.20 K = 10779.75 J = 10.8 kJ. Since the temperature is raised, the reaction is exothermic, so the enthalpy change is negative: -10.8 kJ.

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