Stoichiometry: How many grams of water (H2O) are produced when 4.0 g of hydrogen gas (H2) reacts completely with excess oxygen? Show the balanced equation and the final mass.
Chemistry
ScanSolve AI Answer
Answer
36 g of H2O are produced.
Step-by-step solution
5 stepsBalanced Chemical Equation:
2H₂(g) + O₂(g) → 2H₂O(l)
Calculations:
Molar masses
- H₂: 2 * 1.008 g/mol = 2.016 g/mol
- H₂O: (2 * 1.008 g/mol) + 15.999 g/mol = 18.015 g/mol
Moles of H₂
- Moles H₂ = 4.0 g H₂ / 2.016 g/mol H₂ = 1.984 mol H₂
Moles of H₂O produced (from mole ratio)
- From the balanced equation, 2 moles of H₂ produce 2 moles of H₂O.
- Moles H₂O = 1.984 mol H₂ * (2 mol H₂O / 2 mol H₂) = 1.984 mol H₂O
Mass of H₂O produced
- Mass H₂O = 1.984 mol H₂O * 18.015 g/mol H₂O = 35.744 g H₂O
Rounding to significant figures
- The given mass (4.0 g) has two significant figures.
- Therefore, the final mass should be rounded to two significant figures: 36 g H₂O.
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