Answer to Question #131504 in Organic Chemistry for Deborah Kajinaki

Question

When 25.0 mL of 0.25 mol/L LiOH and 25.0 mL of 0.25 mol/L HCl are mixed together, the temperature warms 15.8o C. What is the molar enthalpy of neutralization for LiOH? (3 marks)

Answer 1

Solution.

$LiOH + HCl = LiCl + H2O$

n(LiOH) = n(HCl)

$m(solution) = V(solution) \times \rho$

m(solution) = 50 g

$Q = c \times m \times \Delta T$

$\Delta H =- Q$

$Q = 4200 \times 0.05 \times 15.8 = 3318 \ J$

$\Delta H = -3318 \ J$

$\Delta H(molar) = \frac{\Delta H}{n(LiOH)}$

$\Delta H(molar) = \frac{-3318}{0.25*0.025} = 530.9 \ kJ/mol$

Answer:

$\Delta H(molar) = 530.9 \ kJ/mol$