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 7.80°C? (The specific heat of the solution is 3.74 joules/gramK.) A. -7.43 kJ

328.4KJ

Explanation:

Before we move on to calculate enthalpy change, we calculate the amount of heat Q

Q= mcΔT

m = density * volume = 250 * 1.25 = 312.5g

c = 3.74J/g.k

ΔT = 7.80 + 273.15K = 280.95K

Q= 312.5 * 3.74 * 280.95 = 328,360.312 J= 328.4KJ(1000J = 1KJ, so divide by 1000)

The enthalpy change in the reaction is same as amount of heat transferred = 328.4KJ