Question

What mass, in grams, of H₂ can be produced from 35.0 g Na?

2 Na + 2 H₂O → 2 NaOH + H₂
6.15 g H₂
3.08 g H₂
1.54 g H₂
4.39 g H₂

Answer 1

The balanced chemical equation shows that 2 moles of Na produce 1 mole of H₂. First, we need to calculate the number of moles of Na in 35.0 g Na:

molar mass of Na = 23.0 g/mol
moles of Na = mass/molar mass = 35.0 g / 23.0 g/mol = 1.52 mol

From the balanced equation, 2 moles of Na produces 1 mole of H₂. Therefore, 1.52 moles of Na produces:

1.52 mol Na × (1 mol H₂/2 mol Na) = 0.76 mol H₂

Finally, we can calculate the mass of H₂ produced using its molar mass:

molar mass of H₂ = 2.02 g/mol
mass of H₂ = moles of H₂ × molar mass of H₂ = 0.76 mol × 2.02 g/mol ≈ 1.54 g

Therefore, the mass of H₂ that can be produced from 35.0 g of Na is approximately 1.54 g. Answer: 1.54 g H₂