Calculate the amount of water required to prepare 500g of 2.5% solution of sugar.
(ii) how many litres of (mass/volume) sugar solution would it take to get 75g of sugar.

(i) We start by calculating the mass of sugar in the solution:

mass of sugar = concentration × solution mass

mass of sugar = 2.5/100 × 500 = 12.5 g  

Then now we can calculate the amount of water:

solution mass = mass of sugar + mass of water

mass of water =  solution mass - mass of sugar

mass of water = 500 - 12.5 = 487.5 g

(ii) We use the following reasoning:

If       500 g solution contains 12.5 g sugar

Then    X g solution contains 75 g sugar

X=(500×75)/12.5 = 3000 g solution

Now to get the amount of solution in liters we use density (we assume that is equal to 1):

Density = mass / volume

Volume = mass / density

Volume = 3000 / 1 = 3000 liters of sugar solution