Concentration is a size which characterizes quantitative composition of solution. By rules IYuPAK the concentration of the dissolved substance is the relation of mass of the dissolved substance, or its quantity, to solution volume (g/l, mol/g), i.e. the relation of non-uniform sizes. Sometimes there is a need to prepare solution of the set concentration. How to make it?
Instruction
1. If there are two solutions, one with concentration – and, another – from percent, then for preparation of the V milliliters of solution of the set concentration of b (provided that b is less and, but it is more c), take also milliliters and percent solution and (V – x) milliliters from percent solution. Considering that a> b> c, work out the equation from which then you will find x: ah + with • (V – x) = bV, then x = (V•b-c) / (a-c).
2. If take with for 0, then the previous equation will take the following form x = V · b/a, ml. Substitute necessary values and solve this equation. So you receive in what ratio it is necessary to take initial solutions, for preparation of solution of the set concentration.
3. For cultivation of the concentrated solutions use the rule of mixture. For example, for preparation of b of percentage solution take two solutions with concentration and and from percent provided that a> b
4. Write down a condition and the received result so. At first write down concentration of the prepared solution (b) and on diagonal from below up to the right of this value you will write down one of answers which belongs to and the % to solution received by the difference of the set concentration (b-c), and in the direction from top to down to the right write down the second answer (and-b) relating to with % to solution. The received answers need to be written down opposite to the corresponding solutions, i.e. opposite x and at.
5. For descriptive reasons, to receive from 30% (x – solution with koncentre. and %) and 15% (solution at with koncentre. with %) solutions of 20% (b), perform the operations described above: 20-15=5 and 30-20=10. Thus, for preparation of 20% of solution mix 5 parts of 30% of solution and 10 parts of 15% of solution. As a result receive 15 parts of 20% of solution.