Final answer:
To find the number of moles of ethanol in a 750-mL bottle of wine, we multiply the volume of wine by the percentage of ethanol to determine the volume of ethanol, convert that volume to mass using ethanol's density, and then divide that mass by ethanol's molar mass to get approximately 1.54 moles.
Step-by-step explanation:
The student is concerned with understanding ethanol (CH3CH2OH), its energy content and its presence in wine, which falls under the subject of Chemistry. Specifically, the question asks for the calculation of moles of ethanol in a 750-mL bottle of wine, given that wine is approximately 12% ethanol by volume, ethanol has a molecular mass of 46.06 g/mol, and a density of 0.789 g/mL. To calculate this, we must first determine the mass of ethanol in the wine, using the density and the volume percentage, and then use the molar mass of ethanol to convert this mass into moles.
First, we find the volume of ethanol: 750 mL * 12% = 90 mL of ethanol. Then, we find the mass of ethanol using its density: 90 mL * 0.789 g/mL = 71.01 g of ethanol. Finally, we convert the mass into moles using the molar mass: 71.01 g / 46.06 g/mol = approximately 1.54 moles of ethanol.