200 mL of an oil-in-water emulsion contains 30.0% oil by volume (oil density 0.85 g/mL). 300 mL of water (density 1.00 g/mL) is added and the emulsion is mixed. Assuming the water of the original emulsion is 140 mL, find the mass percentage of oil in the diluted emulsion (two decimals).

Numerical answer type, answer in %, tolerance 0.02.

Answer: 10.39 %

Oil volume

= 0.300 \times 200 = 60

mL, so oil mass

= 60 \times 0.85 = 51.0

g. Water mass

= 140 + 300 = 440

g. Mass percentage

= 51.0/ (51.0 + 440) \times 100 = 10.39%