A students mixes a bunch of sugar in 300 mL of water. They first measure out 50 mL of the solution and realize that 50 mL has a mass of 75 grams. What is the concentration of the solution?

Answer 1

In order to answer this question, you'll want to make use of the fact that pure water under standard conditions has a density of 1 g/ml. This means that 50 ml of pure water would have a mass of 50 grams. Therefore, we know that our sample has a 25 grams of sugar, in order for the total mass to be 75 grams.

The question doesn't specify what unit of concentration they prefer, so you can use the easiest, which is (mass of solute)/(volume of solvent) which in this case is 25g/50ml or .5 g/ml. If you need to write this in terms of molarity, you can use the molar mass of sugar to convert the 25g into moles and divide by .05 L, as molarity is given by (moles of solute)/(volume of solvent in liters).

Hope this helps and please let me know if you have any more questions!