# Solutions - Formulas and Tips

To study the solutions, it is necessary to know all types of concentrations.

Most concentrations can be calculated by rule of three, but formulas are used a lot. See some of them:

The unit used is g / L.

The unit used is mol / L.

Tip: replacing the number of moles (n) of the formula , then we have the formula:

This concentration has no unity, so we say it is dimensionless.

or

The percentage is expressed in%.

This concentration has no unity, so we say it is dimensionless.

The unit used is N of normal.

The unit used is g.

For certain solutions, we calculate the dilution. We can mix the solutions and we get new concentrations. See the formulas for each case:

When water is added in a solution. We use the following formula:

The molarity (M) can be replaced by common concentration (C).

Tip: On the left side of the formula we put the data of the initial solution, more concentrated and on the right side we put the solution that was added water, the most diluted.

or

### Mixture of different solute solution

In this case, the solutions are acid and base, therefore neutralization reactions. The acid and base react and form a new product.
The chemical reaction and the stoichiometric coefficient must be taken into account.

### Joining concentrations

To facilitate solution calculations, there are some formulas with different concentrations that have been joined.

Tip: beware of common density and concentration. Although they have the paracida formula, they are not the same thing. Density is the density of the solution, therefore mass of the solution and volume of the solution. The common concentration is the mass of the solute by the volume of the solution.

## Solution Formulas Summary Table

 TYPE OF CONCENTRATION FORMULA UNITY COMMON CONCENTRATION g / mL MOLARITY and mol / L MOL NUMBER mol TITLE or dimensionless PERCENT % CONCENTRATION, TITLE AND DENSITY g / mL DENSITY, CONCENTRATION AND TITLE g / mL MOLAR FRACTION dimensionless NORMALITY N GRASS EQUIVALENT g DILUTION - SAME SOLUTION MIX - SOLUTION MIXING OF DIFFERENT SOLUTIONS -