Question

When 5.6g of solid KOH was added to 100gof water, the solid completely dissolves. This was accompanied by a rise of 13℃in the water temperature. Calculate the heat of solution of KOH in kJ/mol of KOH

Answer 1

= 57.7kJ/mol

Step-by-step explanation:

The heat of dissolution is the heat produced when all KOH is dissolved:

KOH(aq) → K⁺(aq) + OH⁻(aq)

To find the heat of solution that is the heat released per mole of KOH we need to convert the mass of KOH to moles and using the equation:

Q = -m×C×ΔT

- Q = Heat; m the mass of solution; C specific heat (We can use specific heat of water 4.184J/g°C), and ΔT change in temperature-

To solve the heat released we can find the heat of solution

Moles KOH -Molar mass: 56g/mol-:

5.6g KOH * (1mol /56g) = 0.1 moles KOH

Heat released:

Q = -106g* 4.184J/g°C* 13°C

Q = -5766J = -5.77kJ

Heat of solution:

5.77kJ / 0.1mol

= 57.7kJ/mol