Question

The density of water is 1.0 gcm–3 and the density of glycerine is 1.3 g cm–3.
Water is added to a measuring cylinder containing 40 cm3
of glycerine so that the density of the
mixture is 1.1 gcm–3. Assume that the mixing process does not change the total volume of the
liquid.
What is the volume of water added?
A 40 cm3 B 44 cm3 C 52 cm3 D 80 cm3

Answer 1

ρ_mix=M/V=(m_g+m_w)/(V_g+V_w )
ρ_mix=(ρ_g V_g+ρ_w V_w)/(V_g+V_w )
1.1=(1.3∙40+1∙V_w)/(40+V_w )
V_w=80 cm^3.