Stoichiometry: 4.0 g of H2 reacts completely with O2 to form H2O. What mass of H2O is produced? Show the full worked solution with the final numeric answer.
ScanSolve AI Answer
Answer
36 g of H2O is produced
Step-by-step solution
6 stepsWhen 4.0 g of H2 reacts completely with O2, 36 g of H2O is produced.
Full Worked Solution:
Write the balanced chemical equation
The reaction between hydrogen gas (H2) and oxygen gas (O2) to form water (H2O) is:
2H2(g) + O2(g) → 2H2O(l)Calculate the molar masses
- Molar mass of H2 = 2 × 1.008 g/mol = 2.016 g/mol
- Molar mass of H2O = (2 × 1.008 g/mol) + 15.999 g/mol = 18.015 g/mol
Convert the given mass of H2 to moles
Moles of H2 = Mass of H2 / Molar mass of H2
Moles of H2 = 4.0 g / 2.016 g/mol ≈ 1.984 mol H2Use the mole ratio from the balanced equation to find moles of H2O
From the balanced equation, 2 moles of H2 produce 2 moles of H2O. This is a 1:1 mole ratio.
Moles of H2O = Moles of H2
Moles of H2O ≈ 1.984 mol H2OConvert moles of H2O to mass
Mass of H2O = Moles of H2O × Molar mass of H2O
Mass of H2O = 1.984 mol × 18.015 g/mol
Mass of H2O ≈ 35.74 gRound to the correct number of significant figures
The given mass (4.0 g) has two significant figures. Therefore, the final answer should also be rounded to two significant figures.
Mass of H2O ≈ 36 gFinal Answer: 36 g of H2O is produced.
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