You will need
  • - scales;
  • - the ability to make and convert a proportion.
Using a scale, measure the mass of a substance, the mass fraction of one of the elements which are known. Since all the substance of a given mass is taken as 100%, make the proportion by finding the ratio of the mass fraction in percent to 100%, and Paranaita is the ratio of the mass ratio of the element and of the whole substance. Transforming the equation, we will obtain the mass value of the element mixture or alloy. The mass is equal to the product of the mass fraction of the element to the mass of all substances, divided by 100 m0=(M•ω%)/100%.For example, if it is known that the ingot of bronze weighing 4 kg mass fraction of copper is 80%, the mass of pure copper will be equal to m0=(4 kg x 80%)/100%. In the calculation get the value of 3.2 kg.
In that case, if the mixture or alloy is composed of many substances and the known mass share of each of them, find them a lot. To do this, each agent will apply the calculation specified in the previous paragraph. Before calculating, always make sure that all of the mass fraction of substances in the sum to 100%, otherwise the calculation will be wrong.After the calculation, and the mass of substances will be found, verify that the total mass of all substances is equal to the mass of the initial substances. For example, 160 g of the solution contains 10% sulphuric acid, 5% nitric and 85% water. The mass of sulfuric acid will be m0=(160g•10%)/100%=16g, the weight of nitric acid m0=(160 g•5%)/100%=8G, and the mass of water m0=(160 kg•85%)/100%=136 g. When a check is received: 16+8+136=160g.
If you know the mass of one element, and its mass proportion, not weighing the substance, determine its mass. The mass of the substance corresponds to 100% mass fraction. Then, accounting for the proportion, Paranaita the ratio of mass fraction to the relevant masses.Calculate the mass of the whole substance, by multiplying the mass of its components by 100% and dividing its mass percentage M=(m0•100%)/ω%. For example, if it is known that to obtain a 10% solution of salt in water was added 12 g of this substance, the mass of the entire solution will be M=(12•100%)/10%=120 G.