HOW TO USE CALCULATOR

3.2. Define the source solution or the solid chemical

The Source area is divided into two parts, each of which represents the composition of one component that is used to create our solution. We can dissolve solid salt in water, dilute a concentrated solution or from two solutions (one that has a higher and one that has a lower concentration than wanted) create a solution with the desired concentration.

Solid compound or stock solution

If the salt, from which the desired solution is being made, is a hydrate it is necessary to add the number of water molecules after formula of the source chemical. The name of the chemical will automatically change to show the number of water molecules in its structure. You can manually change the name by clicking on the name of the compound and then choosing a new name from the list or writing your own in and then pressing enter.

Solutions used in the laboratory are usually made from either solid (dry) chemical or stock solutions. If the "Solid" option is selected the number under the chemical's formula indicates its purity ("Purity of solid compound") and if the "Solution 1" option is selected the number indicates its concentration ("Concentration of first solution").

In the "Concentration of first solution" field type the concentration of the stock solution and choose a unit in which the concentration is expressed. If you expressed the components of the solution in mass fraction (%, ‰ - per mille, or ppm - parts per million) it will become an active field and you will be able to add in the density of the solution. If there is a note in the chemical database about the existence of an equation for calculating density (Density equation: YES) the program itself will input the density wherever appropriate for the desired solution. In case you manually change the density (blue numbers) the changed density will persist until the concentration of the solution changes.

For some entries for which specific molecular masses are not known (eg, proteins), the best way to express the concentration of the solution is mass amounts per liter.

Solvent or second stock solution

The second part of the Source area is reserved for the solvent (usually water). In case there is an equation for calculating the density, water temperature will automatically set itself to the temperature at which the density was measured.

By choosing the Solution 2 option you can prepare a mixture of two solutions of different concentrations or you can increase the concentration of a solution by adding solid salt.

SolCalc automatically calculates the necessary amount of chemicals as soon as some information changes.