If I want to make 1 litre of a solution with a dilution rate of 1:50 how much concentrate must I add to ho much water ?
Let us clarify things with a few definitions.
A solution is made up of a solute and a solvent.
The solvent is what dissolves the solute.
The dissolved solute is then referred to as the solution.
Assume that we initially have a volume of solute, v1 ml, with a concentration of c1 g/ml.
We want to end up with a (larger) volume, v2 ml, of solution with a concentration c2 g/ml.
Since the mass of solute remains constant, then we can balance the amount of solute before and after dilution with the equation,
v1c1 = v2c2
You want to make up a litre of solution, so v2 = 1000 ml.
The final concentration is given as 1:50, so c2 = 0.02 g/ml.
Then, v1c1 = v2c2 = 1000*0.02 = 20.
Now, v1 is the amount of concentrate that you need to add the water solvent to.
So you will need to have been told what c1 is, the concentration of the solute.
When you know what c1 is, then use v1c1 = 20 to work out how nuch concentrated solute you should start with, then subtract that from 1000 ml (v2) to find out how wuch water will need to have been added.