Solutions
Distinguish between the terms solute, solvent, solution and concentration (g dm-3 and mol dm-3)
Solute – This is the substance which has been dissolved.
Solvent – The bulk substance in which the solute was dissolved
Solution – This is made up of the solute and the solvent. The solution is called aqueous if the solvent is water
Concentration – This is an expression of how much solute there is dissolved in the solution. This can be expressed in g dm-3 or mol dm-3.
Solve problems involving concentration, amount of solute and volume of solution
C = concentration of solution – mol dm-3
n = number of moles of solute – mol
V = volume of solution – dm3
For example:
Calculating Concentrations of Components of Solutions
The concentration of individual ions in solution is proportional to the chemical formula of the compound. If two or more solutions are mixed and there is no chemical reaction, the concentration of each individual ion can be calculated by determining the total amount of that ion present and dividing by the final volume of the solution.
For example:
Dilution of Solutions
When a solution is diluted, the number of moles of solution remains the same, but the volume changes.
c1 = initial concentration
V1 = initial volume
c2 = diluted concentration
V2 = diluted volume
For this equation to work, the units must be constant, not necessarily mol dm-3 or dm3
For example:
Limiting Reagent with Solutions
Finding Amounts of Products
| Substance | Lead (II) Nitrate | Potassium Iodide |
| Volume | 20.0cm3 | excess |
| Concentration | 0.250mol dm-3 | 0.500mol dm-3 |
