Instruction

1

If there are two

**solution**, one concentration and the other with percent, to prepare V ml**of a solution**of a given**concentration of**b (provided that b is less and no more), take x milliliters of a percent**solution**and (V – x) ml with a percent**solution**. Given that a>b>c, write down the equation, from which we find x: ax+s•(V – x)= bV, then x = V•(b-c)/(a-c).2

If you take with for 0, the previous equation takes the form x = V•b/a, ml. making the appropriate substitutions and solve this equation. So you get the proportions in which you need to take the original solutions, for the preparation

**of a solution**of a given**concentration**.3

For dilution of concentrated solutions use the rule of mixing. For example, for the preparation of the b percentage

**of the solution**take two**of the solution**with the concentrations of a and C per cent, provided that a>b4

Record the condition and the result. First, write the concentration of the prepared

**solution**(b) and diagonally upward to the right of this value, write one of the answers that refers to a% of the solution obtained by difference between the specified concentrations (b-C), and from above downward to the right, record the second response (a-b) related to the% solution. Get the answers you need to record in the appropriate solutions, i.e., opposite to x and y.5

For clarity, to get from 30% (x – R-R with conc. and%) and 15% (p-p y with conc. with%) a solution of 20%(b), follow the steps described above: 20-15=5 and 30-20=10. Thus, for preparing 20%

**solution**mix 5 parts of 30% R-RA and 10 parts of 15% R-RA. The result is 15 parts 20% R-RA.