Final answer:
The molarity of ethanol in a 92-proof ethanol/water solution is approximately 8.2 M.
Step-by-step explanation:
Proof is defined as twice the percent by volume of pure ethanol in a solution. A 95% ethanol solution is 190 proof, meaning it contains 95% pure ethanol by volume. To find the molarity of ethanol in a 92-proof ethanol/water solution, we first need to convert the proof to the percent by volume of ethanol.
We can use the formula:
Percent by volume of ethanol = Proof/2.
Substituting the given proof (92) into the formula, we get:
Percent by volume of ethanol = 92/2 = 46%.
The density of ethanol is given as 0.80 g/cm³.
To find the molarity of ethanol, we need to calculate its concentration in moles per liter.
We can use the formula:
Molarity (M) = (Density (g/cm³) * Percent by volume of ethanol * 10) / Molar mass of ethanol.
The molar mass of ethanol is 46.07 g/mol.
Plugging in the given values, we get: Molarity (M) = (0.80 * 46 * 10) / 46.07 = 8.196 M.
Therefore, the molarity of ethanol in a 92-proof ethanol/water solution is approximately 8.2 M.
Learn more about Molarity of Ethanol