# A bottle of wine contains 12.5% ethanol (#CH_3CH_2OH#) by volume. The density of ethanol is 0.789 g/cm^3 and the density water is 1.000 g/cm^3. How do you calculate the concentration of ethanol in terms of mass percent of ethanol?

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You may assume wine i made entirely of water and ethanol.

You may assume wine i made entirely of water and ethanol.

##### 1 Answer

The mass percent of ethanol is 10.1 %.

#### Explanation:

Percent of alcohol by volume (**ABV**) is the volume of ethanol in **solution**.

It is **impossible** to answer this question because we don’t know the volume or the density of the wine.

The problem arises because the volume obtained by mixing water and ethanol is less than the sum of the original volumes.

For example, the volume of

The density of 12.5 % ABV at 20 °C is

Now, we can calculate the mass percent of the ethanol.