A certain alcoholic beverage contains only ethanol (C2H6O) and water. When a sample of this beverage undergoes com-bustion, the ethanol burns but the water simply evaporates and is collected along with the water produced by combus-tion. The combustion reaction is When a 10.00 g sample of this beverage is burned, 11.27 g of water is collected. What is the mass in grams of ethanol, and what is the mass of water in the original sample?

Verified step by step guidance

1. Identify the chemical reaction for the combustion of ethanol: \( \text{C}_2\text{H}_6\text{O} + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 3\text{H}_2\text{O} \).
2. Calculate the moles of water produced from the combustion using the mass of water collected (11.27 g) and the molar mass of water (18.02 g/mol).
3. Determine the moles of ethanol that reacted using the stoichiometry of the balanced equation, where 1 mole of ethanol produces 3 moles of water.
4. Calculate the mass of ethanol in the original sample using the moles of ethanol and its molar mass (46.08 g/mol).
5. Subtract the mass of ethanol from the total mass of the sample (10.00 g) to find the mass of water in the original sample.

Key Concepts

Combustion Reaction

A combustion reaction is a chemical process in which a substance reacts rapidly with oxygen, producing heat and light. In the case of ethanol, the reaction can be represented as C2H6O + 3O2 → 2CO2 + 3H2O. Understanding this reaction is crucial for determining the products formed and the stoichiometry involved, which helps in calculating the amounts of reactants and products.

Stoichiometry

Stoichiometry is the calculation of reactants and products in chemical reactions based on the conservation of mass. It involves using balanced chemical equations to relate the quantities of substances involved. In this question, stoichiometry will be used to determine the mass of ethanol in the sample by analyzing the mass of water produced during combustion.

Mass Conservation

The principle of mass conservation states that mass is neither created nor destroyed in a chemical reaction. This means that the total mass of the reactants must equal the total mass of the products. In this scenario, knowing the total mass of the beverage and the mass of water collected allows for the calculation of the mass of ethanol, as the mass of the original sample must equal the sum of the masses of ethanol and water.