You will need
  • - handle;
  • paper;
  • - the periodic table;
  • calculator.
To find the mass fraction (percentage concentration) of a substance, divide its mass by the total mass of the solution (mixture). The result will be in fractions of a unit, which can then convert into a percentage that will also be true. For example, given the task: to prepare the solution took 150 g of water and 50 g sugar. You must calculate the percentage concentration of the solute. For the solution first, write the formula and then find the optimum value:ω (sugar)= m(sugar)/m(solution) = 50/ (150+50) =0,25 * 100% = 25%the solution contains 25% sugar.
When calculating the molar concentration, you need the amount of substance divided by the total volume of the solution. The unit of measure in this case would be mol/L. the Formula for calculation is as follows: C = n(solute)/V, where C is the molar concentration (mol/l);n – amount of substance (mol);V is the total volume of the mixture (liter).
Normal concentration is expressed in gram equivalent/liter and represents the number of equivalents of a certain substance in 1 l of solution, which is, in chemical reactions, 1G of hydrogen or 8 g of oxygen. Suppose you want to calculate the normality of 70% sulfuric acid, the density of which is equal to 1,615 g/l. the conditions of the problem it is clear that 100 g of solution contains 70 grams of acid. So first find the volume of a given solution: V = 100/1,615 = accounting period 61.92 (ml). Then calculate the mass of H2SO4 in 1 liter of solution: m(H2SO4) = 1000*70/61,92 = 1130,49 (g). And then calculate the normality, considering that the acid is dibasic:SN = m*z/ M =1130,49*2/98 = N of 23.06.
If you want to calculate molalou the concentration of the solution (molality), use the following formula: Cm = n/m, gdes – molalla concentration is measured in mol/kg;n – number of a certain substance in moles;m is the total mass of the solution in kilograms.Unlike molarity molalla concentration depends on the temperature conditions of the reaction.