12.1.2Experimental Chemistry

Solutions — Combined Science 0653 - Chemistry Revision Notes & Topical Questions

5 min read 8 parts Lesson 7 of 10 Unit quiz

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Part 1 of 6Making a solution

Solution

Solute

Solvent

Solution

Solution The mixture formed when a solute has dissolved in a solvent, such as seawater itself.

Soluble

Soluble A substance that will dissolve in a given solvent. Salt is soluble in water.

Insoluble

Saturated solution

Saturated solution A solution that holds the maximum amount of dissolved solute at a given temperature, so any more added stays undissolved.
Saturation depends on temperature, since most solids dissolve better in hot water.
- The Dead Sea is close to saturated with salt.

Mix the two solids with water and stir so that the soluble one dissolves.

Pour the mixture through filter paper in a funnel.

The insoluble solid is trapped on the paper as the residue.

The solution that passes through is the filtrate.

Evaporate the water from the filtrate to leave the soluble solid behind.

Term	Meaning	Example
Filtrate	The liquid or solution that has passed through a filter	Coffee in the cup
Residue	What remains after filtration, evaporation, distillation or a similar process	Coffee grounds in the filter paper

Situation	What is happening	Terms to use
Stirring sugar into hot tea	The sugar particles spread out evenly among the water particles until no solid can be seen.	Sugar is the solute, water is the solvent and the sweet tea is the solution.
Adding salt to water until some stays at the bottom	No more salt can dissolve at that temperature, so the extra remains as a solid.	The liquid is a saturated solution and the leftover salt is undissolved.
Pouring muddy water through a filter	Soil is insoluble and cannot pass through the tiny holes in the paper, whereas water passes straight through.	The soil is the residue and the clear water is the filtrate.
Heating a salt solution until the water has gone	The solvent evaporates and the dissolved solid is left behind.	The salt that remains is the residue.

Insoluble solid and a liquid

Insoluble solid and a liquid Use filtration, because the solid particles are too large to pass through the filter paper.

Dissolved solid and a solvent

Dissolved solid and a solvent Use evaporation,
- or crystallisation if crystals of the solid are wanted,
- because the solid is too small to be filtered out.

Link to solubility

Link to solubility The method chosen always depends on which substances are soluble and which are insoluble in the solvent being used.

Term	Meaning
Solute	The substance that dissolves in a solvent.
Solvent	The liquid in which a solute dissolves.
Solution	A mixture of a solute completely dissolved in a solvent.
Saturated solution	A solution containing the most solute that can dissolve at a given temperature.
Soluble	Able to dissolve in a particular solvent.
Insoluble	Unable to dissolve in a particular solvent.
Filtrate	The liquid that passes through a filter.
Residue	The solid left behind on the filter paper or after evaporation.

Swapping solute and solvent. The solvent is the liquid doing the dissolving and the solute is what disappears into it.

Using 'solution' for the dissolved substance alone. A solution is the whole mixture.

Forgetting that saturation refers to a specific temperature.

Calling the liquid that passes through the filter the residue. That liquid is the filtrate.

Describing dissolving as melting. A dissolving solid is spread out among the solvent particles and is not changing state.

Last updated: 20 October 2026