What is the mass of 0.5 l of alcohol, milk, mercury?

The volume of 1 liter is equal to 1 dm³ or 0.001 m³.
V = 0.5 l = 0.0005 m³.
Mass is found by multiplying volume by density, which can be found in reference books:
M = rV.
The density of alcohol is 789.3 kg / m³,
density of milk – 1030 kg / m³,
mercury density – 13540 kg / m³.

MS = 0.0005 m³ * 789.3 = 0.394 kg;
Mm = 0.0005 m³ * 1030 kg / m³ = 0.515 kg;
Мр = 0.0005 m³ * 13540 kg / m³ = 6.77 kg.

Answer: The mass of alcohol is 0.394 kg, milk – 0.394 kg, mercury – 6.77 kg.