Many reactions in your body and many in your environment occur between substances in solution. Practicing chemists use reactions in solution both to prepare substances and to determine the composition of unknown substances. This is because
- reactions may be faster in solution where there is better mixing of the reactants.
- working with a small quantity of substance in a manageable amount of solution is easier than working with a small mass of the pure substance.
Concentration measures the
amount of solute (substance dissolved) in a
volume of solution.
Chemists commonly use concentrations in
where the amount is in moles (
n) and volume (
V) is in
s. Thus
the concentration of the solution can be calculated if the amount in moles of solute dissolved is divided by the volume of the solution in
s.
required to make a solution of a certain volume depends on how the solute is added.
If solid solute is used, the amount in moles is calculated by dividing the mass
m in grams of the substance by the mass of one mole (molar mass
M ) of the substance
If solute is added as a solution, the amount in moles is calculated by multiplying the volume and concentration of the solution added.