A substance has a density of 2kg/L. 4kg of this substance is then placed in 10 liters of water. What is the volume percent of this in 10 mL water.

Question

A substance has a density of 2kg/L. 4kg of this substance is then placed in 10 liters of water. What is the volume percent of this in 10 mL water?

Answer 1

Tammy - The question seems a bit misleading - you are asking the volume percent in a 10 mL sample of water. The volume percent would be the same no matter what the sample size, it's a ratio concentration unit.

*IF* we assume that the substances are miscible, and also that there is no volume change upon mixing (which is really a bad assumption), you can calculate that you will be adding  4 kg x (1 L / 2 kg) = 2 L of the other substance to 10 L of water, giving you a total volume of 12 L.

 

The percent by volume of the substance would be 2 L substance / 12 L solution mixture = 0.167 x 100% = 16.7 %

 

If this is a General Chemistry 1 class, or an Introduction to Chemistry class, then that is probably your answer.  If this is a higher level class, this might not be what they are looking for.