Data

Mass of hydrogen peroxide (H₂O₂) = 12g
Molar mass of hydrogen peroxide (H₂O₂) = 34g/mole
Molar volume at S.T.P = 22.4dm³/mole
Asked:
i. The volume of water formed.
ii. The volume of oxygen formed.

Convert 12g of H₂O₂ into mole

Mole = mass / Molar mass
= 12g / 34g/mole
= 0.3529411765 mole of H₂O₂

i. Find the volume of water formed.

The chemical equation for the reaction

2(H₂O₂)_(g) → catalase 2H_2(l) + O_2(g) catalyst

Make mole equivalent between H₂O₂ and water (H₂O)

2 moles of (H₂O₂) Ξ 2 moles of H₂O
0.3529 moles of (H₂O₂) Ξ ?? of H₂O

= (0.3529 mole × 2 mole) / 2 moles
= 0.352941179 mole of H₂O

Convert 0.352941176 of H₂O into volume

Volume = mole × molar volume
= 0.352941176 mole × 22.4dm³/mole
= 7.9dm³

7.9dm³ of water was formed at S.T.P

ii/ Calculate the volume of oxygen gas formed

use the mole of H₂O₂ with that of O₂

2 moles of H₂O₂ Ξ 1 mole of O₂
0.3529 mole of H₂O₂ Ξ ?? of O₂

X = (0.3529 mole × 1 mole) / 2 moles
= 0.17645 moles O₂

Convert 0.17645 mole of O₂ into volume at S.T.P

Mole (n) = volume (dm³) / Molar volume (22.4dm³/mole)
Volume = mole × molar volume
= 0.17645 mole × 22.4dm³/mole
= 3.95248dm³

3.95248dm³ of oxygen gas was produced