A reaction is 2 H2 + O2 - 2 H2O. If 4.0 g of H2 reacts completely with excess O2, what mass of H2O is…

Question

A reaction is 2 H2 + O2 -> 2 H2O. If 4.0 g of H2 reacts completely with excess O2, what mass of H2O is produced? Show the worked solution.

ScanSolve AI Tutor · Accepted Answer

When 4.0 g of H2 reacts completely with excess O2, 36 g of H2O is produced. Worked Solution: 1. 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 2. Convert the 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 H2 3. Use the mole ratio from the balanced equation to find moles of H2O: The balanced equation is 2 H2 + O2 -> 2 H2O. From the equation, 2 moles of H2 produce 2 moles of H2O. The mole ratio is 1:1. Moles of H2O = Moles of H2 * (2 mol H2O / 2 mol H2); Moles of H2O = 1.984 mol H2 * (1 mol H2O / 1 mol H2) = 1.984 mol H2O 4. Convert 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 = 35.744 g 5. Round to appropriate significant figures: The given mass (4.0 g H2) has two significant figures. Therefore, the answer should also be rounded to two significant figures. Mass of H2O = 36 g

A reaction is 2 H2 + O2 -> 2 H2O. If 4.0 g of H2 reacts completely with excess O2, what mass of H2O is produced? Show the worked solution.

Answer

Step-by-step solution

Calculate the molar masses

Convert the mass of H2 to moles

Use the mole ratio from the balanced equation to find moles of H2O

Convert moles of H2O to mass

Round to appropriate significant figures

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