you need
  • - periodic table;
  • - the formula for calculating the mass fraction.
Guide
1
Calculate the mass fraction of by definition.Since the mass of matter is composed of an array of elements that make it up, then share any constituent element accounts for some of the weight of the substance.Mass fraction of a solution is the ratio of the mass of the solute to the weight of the total solution.
2
weight of the solution is the sum of the mass of the solvent (usually water) and substance.Mass fraction of the mixture is the ratio of the mass of the substance to the weight of the mixture containing the substance.T
he result multiply by 100%.
3
Find share mass exit by the formula ω = Mg / Mn, where Mn and Mg - the estimated value of the real and the resulting output material (mass), respectively.Calculate the estimated weight of the reaction equation, using the formula m = nM, where n - number of chemical substances, M - molar mass of a substance (the sum of the atomic weights of all the elements included in the substance), or the formula m = Vρ, where V- volume of the substance, ρ- its density.The amount of substance in turn be replaced by a formula n = V / Vm and also find out the reaction equation.
4
Mass share element of a compound calculated using the periodic table.Fold the atomic weights of all the elements contained in the substance, if necessary, by multiplying the indices.You get the molar mass of the substance.Find the molar mass of an element from the periodic table.Calculate the mass fraction of , dividing the molar mass of the element in the molar mass of the substance.Multiply by 100%.