In the process of alcoholic fermentation of glucose, ethanol and carbon (IV) oxide were formed.

In the process of alcoholic fermentation of glucose, ethanol and carbon (IV) oxide were formed. Determine the mass fraction of alcohol (%) in the solution obtained by dissolving 0.2 mol of ethanol in water with a mass of 200 g.

1. Calculate the mass of a portion of ethanol:

m (C2H5OH) = n (C2H5OH) * M (C2H5OH);

M (C2H5OH) = 2 * 12 + 5 + 16 + 1 = 46 g / mol;

m (C2H5OH) = 0.2 * 46 = 9.2 g;

2. Find the mass of the alcohol solution:

m (solution) = m (C2H5OH) + m (H2O) = 9.2 + 200 = 209.2 g;

3. Determine the mass fraction of ethanol:

w (C2H5OH) = m (C2H5OH): m (solution) = 9.2: 209.2 = 0.044 or 4.4%.

Answer: 4.4%.