Final answer:
Oxygen is the limiting reactant and hydrogen is the excess reactant. The theoretical yield of water is 20.2725 g, and the percent yield is approximately 59.22% given an actual yield of 12 g of water. The reaction is classified as a synthesis reaction.
Step-by-step explanation:
The limiting reactant is the reactant that will be completely used up first during a chemical reaction, determining the maximum amount of product that can be formed. The excess reactant is the substance that is not completely used up when the reaction is complete. To find these, we compare the mole ratios of the reactants given with their stoichiometric coefficients in the balanced equation.
The balanced equation for the reaction of hydrogen and oxygen to produce water is:
2 H₂(g) + O₂(g) → 2 H₂O(l)
This indicates that 2 moles of hydrogen react with 1 mole of oxygen to produce 2 moles of water. Given 10 g of hydrogen and 18 g of oxygen, we convert these amounts to moles using the molar masses (2 g/mol for H₂ and 32 g/mol for O₂):
10 g H₂ × ⅒ (1 mol H₂ / 2 g H₂) = 5 moles H₂
18 g O₂ × ⅒ (1 mol O₂ / 32 g O₂) = 0.5625 moles O₂
According to the stoichiometry of the reaction, we would need half the moles of oxygen to react completely with the hydrogen. Hence, 2.5 moles of oxygen would react with 5 moles of hydrogen, but we only have 0.5625 moles of oxygen. Thus, oxygen is the limiting reactant, and hydrogen is the excess reactant.
The amount of water produced is based on the limiting reactant.
(0.5625 moles O₂) × (2 moles H₂O / 1 mole O₂) = 1.125 moles H₂O
Converting moles of water produced to grams:
1.125 moles H₂O × (18.02 g H₂O / 1 mole H₂O) = 20.2725 g H₂O
However, if the actual yield is 12 g of H₂O, the percent yield can be calculated:
Percent Yield = (Actual Yield / Theoretical Yield) × 100%
Percent Yield = (12 g / 20.2725 g) × 100% ≈ 59.22%
The theoretical yield is 20.2725 g of water.
Since the reaction is a combination of elements to form a compound, it is a synthesis reaction.