Question

The enthalpy change for 2KClO3 = 2KCl +3O2

Answer 1

To calculate the enthalpy change for the given reaction, we need to consider the enthalpy values of the reactants and products.

The balanced equation for the reaction is:
2KClO3 → 2KCl + 3O2

Given:
- The enthalpy change of formation for KClO3 (ΔHf°) = -395 kJ/mol
- The enthalpy change of formation for KCl (ΔHf°) = -436 kJ/mol
- The enthalpy change of formation for O2 (ΔHf°) = 0 kJ/mol (since it is an element in its standard state)

The enthalpy change (ΔH) for the reaction can be calculated using the following formula:

ΔH = ∑(nΔHf° products) - ∑(nΔHf° reactants)

Where n is the stoichiometric coefficient of each species in the balanced equation, and ΔHf° is the standard heat of formation.

For the reactants:
ΔH = (2mol)(-436 kJ/mol) + (3mol)(0 kJ/mol) - (2mol)(-395 kJ/mol)
= -872 kJ/mol + 0 kJ/mol + 790 kJ/mol
= -82 kJ/mol

Therefore, the enthalpy change (∆H) for the given reaction is -82 kJ/mol.