Solution and suspension
| Aspects | Solution | Suspension |
| Composition | A solute dissolved in a solvent | Insoluble, suspended particles in a liquid or gas |
| Size of particles | Tiny and well dispersed | Larger than those in a solution |
| Nature of solution | Transparent and clear, allows light to pass through | Opaque and cloudy, does not allow much light to pass through |
| When left to stand | No sediment seen | Solid particles settle to the bottom or float at the surface |
| Filtration | No residue left on the filter paper | Residue left on the filter paper |
| Type of solution | Homogeneous because its properties are the same throughout | Non-homogeneous (cloudy) |
| Examples | Salt solution, acids , alkalis | Some medicines, calamine lotion |
Solubility
1. Solubility – refers to the maximum amount of a solute in grams that will dissolve in given amount of solvent (liquid).
2. For example – the solubility of sodium chloride in water at a temperature of 30oC is 39 g per 100ml of water. This means that 39g of sodium chloride dissolves in 100 ml of water at 30oC to form a saturated solution.
The factors affecting the solubility of a solute are:
1. The nature of solvent
- The solubility of a substance is different in different solvents.
- A solute may have a lower solubility in one solvent, but a higher solubility in another solvent.
- For example:
· Sugar dissolves faster in water than in another solvent like alcohol and petrol.
· Iodine crystals are very soluble in alcohol but dissolve slightly in water.
2. The nature of solute
- Different solids (solutes) have different solubilities in a given solvent.
- Some solids are more soluble than others.
- For examples:
· Sugar is more soluble in water than flour.
3. The temperature of the solution
- The solubility of solids in liquid solvents increases with temperature but the solubility of gases in liquid solvents decreases with temperature.
- Most substances dissolve more readily at higher temperature than at lower temperatures.
- Examples:
· More sugars dissolves in hot, boiling water than in equal amount of ice-cold water.
Ø The rate of dissolving a solute – refers to how fast a substance can dissolve in a given amount of solvent, at a particular temperature.
Ø It refers to the time taken for the dissolving process, from the time the solute is added to the solvent until it has completely dissolved.
Ø The rate of dissolving a solute is affected by the following factors:
a) The size of the solute particles.
b) The rate of stirring the solvent
c) The temperature of the solvent
d) The volume of the solvent.
Indicator
| Indicator used | acidic | neutral | Alkaline |
| Universal indicator | Red | green | Violet |
| Phenolphthalein | Colourless | Colourless | Pink |
| Litmus solution | red | Purple | blue |
