There are several formulas for finding of volume of solution. Depending on what is given in a statement of the problem it is possible to choose one of them. Time of data in a task it is not enough, it is also necessary to apply additional formulas to their location.
Instruction
1. One of the most often used formulas looks so: V = m/p, where V - volume, m - the weight (g), p - density (g/ml). Respectively, if these sizes are given, it is possible to find volume without effort. Sometimes happens so that the mass of substance is not given, but the amount of substance (n) is given and it is specified what this substance. In this case we find weight on a formula: m = n*M where n is amount of substance (mol), and M - the molar weight (g/mol). It is the best of all to consider it on the example of a task.
2. The amount solutionof the substance sulfate of sodium is equal to 0.2 mol, and density - 1.14 g/ml, to find its volume. At first we write a basic formula for finding of volume: V = m/p. From this formula on a statement of the problem we have only density (1.14 g/ml). We find weight: m = n*M. The amount of substance is given, it was necessary to determine molar weight. Molar weight is equal to the relative molecular weight which in turn consists of relative atomic masses of the simple substances which are a part difficult. Actually everything is simple: its relative atomic mass is specified in Mendeleyev's table under each substance. A formula of our substance Na2SO4, we consider. M (Na2SO4) = 23*2+32+16*4=142 g/mol. We substitute in a formula, we receive: m = n*M = 0.2*142 = 28.4 g. Now we substitute the received value in the general formula: V = m/p = 28.4/1.14 = 24.9 ml. The task is solved.
3. There are still other types of tasks where there is a solution volume - it is tasks on concentration of solution. The formula necessary for finding of volume of solution looks so: V = n/c, where V – the volume of solution (l), n – amount of the dissolved substance (mol), with – molar concentration of substance (mol/l). If necessary to find amount of the dissolved substance, it can be done on a formula: n = m/M where n is amount of the dissolved substance (mol), m is weight (g), M – the molar weight (g/mol).