Final answer:
The percentage of alcohol content on an alcoholic bottle indicates the volume of alcohol per 100 mL of the solution, not the entire bottle or a standard serving size.
Step-by-step explanation:
The percentage of alcohol content on an alcoholic bottle refers to the volume of alcohol per 100 milliliters (mL) of the total solution. In other words, if a bottle says it has 5% v/v alcohol, this means there are 5 mL of alcohol for every 100 mL of the solution overall in the bottle. This does not refer to the entire bottle unless the bottle is exactly 100 mL, nor does it refer to a standard serving size unless that serving size is also 100 mL. It is a ratio that can be applied to understand the amount of alcohol in any given volume of the solution based on that percentage.
For example, rubbing alcohol is often sold as a 70% vol aqueous solution, which means there are 70 mL of isopropanol for every 100 mL of solution. Using the density of isopropyl alcohol (0.785 g/mL), one can calculate the exact grams of isopropyl alcohol in any given volume of the solution.