1.5 m3 of water is mixed with 0.50 m3 of alcohol. The density of water is 1000 kg m-3 and the density of alcohol is 800 kg m-3.

Question 36

1.5 m³ of water is mixed with 0.50 m³ of alcohol. The density of water is 1000 kg m^-3 and the density of alcohol is 800 kg m^-3.

What is the density of the mixture with volume 2.0 m³?

A 850 kg m^-3                    B 900 kg m^-3                    C 940 kg m^-3                    D 950 kg m^-3

Reference: Past Exam Paper – June 2011 Paper 11 Q19

Solution:

Answer: D.

Density of mixture = total mass / total volume

Total volume = 2.0 m³

For water,

Density = 1000 kg m^-3

Volume = 1.5 m³

Mass = Density × Volume = 1000 × 1.5 = 1500 kg


For alcohol,

Density = 800 kg m^-3

Volume = 0.5 m³

Mass = Density × Volume = 800 × 0.5 = 400 kg

Total mass = 1500 + 400 = 1900 kg


Density of mixture = total mass / total volume

Density of mixture = 1900 / 2.0 = 950 kg m^-3