Question

For the following reaction: C₃H₄ + 4O₂ → 3CO₂ + 2H₂O. What mass of H₂O will be produced from the combustion of excess hydrocarbon and 35.0 g O₂?

a) 19.7 g
b) 9.85 g
c) 39.4 g
d) 31.1 g
e) 62.2 g

Answer 1

To find the mass of H2O produced, we need to determine the limiting reagent first. The equation tells us that the stoichiometric ratio of O2 to H2O is 4:2, which simplifies to 2:1. We can use that ratio to convert the mass of O2 given (35.0 g) to the mass of H2O produced. Therefore, the mass of H2O produced is 9.85 g.

Step-by-step explanation:

To find the mass of H2O produced, we need to determine the limiting reagent first. The equation tells us that the stoichiometric ratio of O2 to H2O is 4:2, which simplifies to 2:1. We can use that ratio to convert the mass of O2 given (35.0 g) to the mass of H2O produced.

Step-by-step:

1. Calculate the molar mass of O2: 32.0 g/mol
2. Calculate the moles of O2: 35.0 g / 32.0 g/mol = 1.094 mol
3. Use the stoichiometric ratio to convert moles of O2 to moles of H2O: 1.094 mol O2 * (2 mol H2O / 4 mol O2) = 0.547 mol H2O
4. Calculate the molar mass of H2O: 18.02 g/mol
5. Calculate the mass of H2O produced: 0.547 mol H2O * 18.02 g/mol = 9.85 g

Therefore, the mass of H2O produced is 9.85 g. So, the correct answer is b) 9.85 g.