Question

3. How much heat (in kl) is released when 1.65 mol NaOH(s) is dissolved in water? (The molar heat of solution of NaOH is -445.1 kJ/mol.)

a. -1.36x 10-3 kJ
b. -7.34 x 10^2 km
c. -2.69 x 10^1 km
d. -2.80 x 10^2 km

Answer 1

The heat released : b. -7.34 x 10² kJ

Further explanation

Given

1.65 mol NaOH

The molar heat of solution of NaOH is -445.1 kJ/mol

Required

Heat released

Solution

ΔH solution = Q : n

ΔH solution = enthalpy of solution(-=exothermic, +=endothermic)

Q = heat released/absorbed

n = moles of solute

Input the value :

Q = ΔH solution x n

Q = -445.1 kj/mol x 1.65 mol

Q = -734.415 kJ