Question

How would I find the quantity of heat absorbed or released when 2.0g of LiOH is dissolved in 100g of H₂0 when the enthalpy of the solution is -23.6KJ/mol?

Answer 1

1.97kJ of energy are released.

Step-by-step explanation:

The dissolution of LiOH in water is:

LiOH(s) → Li⁺(aq) + OH⁻(aq) ΔH = -23.6kJ

That means, when 1 mole of LiOH is dissolved, there are released (Because of the - in the enthalpy) 23.6kJ

2.0 g of LiOH (Molar mass: 23.95g/mol) are:

2.0g LiOH × (1 mol / 23.95g) =0.0835 moles of LiOH.

As 1 mole of LiOH release 23.6kJ, 0.0835moles release:

0.0835moles × (-23.6kJ / 1mole) = 1.97kJ of energy are released