Question

Hydrogen gas reacts with oxygen to form water. 2H2(

Answer 1

The reaction is as follows:
2 H₂(g) + O₂(g) → 2 H₂O(g) . ΔH = - 483.5 kJ
Using the change in enthalpy and heat, calculate the moles as follows:
Moles of H₂ = - $\frac{amount of heat released}{ΔH}$ x 2 mol H₂
                  = - 216 kJ / (-483.5 kJ) x 2 mol H₂ 
                  = 0.893 mol H₂
Calculate the mass of H₂ using the moles and molar mass as follows:
0.893 mol H₂ x (2.02 g H₂ / 1 mol H₂) = 1.79 g H₂
Therefore, the mass of hydrogen gas is 1.79 g