24. Hydrogen peroxide can decompose to water and oxygen according to:



2H2O2 (l) + -----------> 2H2O (l) + O2 (g) ^ H = -196 kJ



What is the enthalpy change accompanying the reaction of 5.00 g H2O2 (l) according to the above mentioned reaction ?

196 kJ x (5.00g/(2*molar mass H2O2) = ??

To determine the enthalpy change accompanying the reaction of 5.00 g H2O2, we can use the concept of stoichiometry.

1. Convert the mass of H2O2 from grams to moles using the molar mass of H2O2. The molar mass of H2O2 is 34.0147 g/mol.

Moles of H2O2 = mass of H2O2 / molar mass of H2O2
= 5.00 g / 34.0147 g/mol

2. Set up a ratio using the stoichiometry of the balanced equation. From the balanced equation, we can see that 2 moles of H2O2 produce 1 mole of O2.

Moles of O2 = (moles of H2O2) x (1 mole O2 / 2 moles H2O2)

3. Multiply the moles of O2 by the molar enthalpy change (-196 kJ/mol) to find the enthalpy change of the reaction.

Enthalpy change = (moles of O2) x (enthalpy change per mole)
= (moles of O2) x (-196 kJ/mol)

4. Substitute the calculated value of moles of O2 into the equation to find the enthalpy change.

Enthalpy change = [(5.00 g / 34.0147 g/mol) x (1 mole O2 / 2 moles H2O2)] x (-196 kJ/mol)

By following these steps, you can determine the enthalpy change accompanying the reaction of 5.00 g H2O2.