Solutions, Solubility, and Separation Techniques

Solution: A homogeneous mixture formed when a solid, liquid, or gas dissolves in a liquid. Solutions are transparent and do not scatter light.
Solute: The substance (solid, liquid, or gas) that dissolves in a liquid to form a solution. It is present in a smaller amount compared to the solvent.
Solvent: The liquid in which a solute dissolves. It is present in a larger amount compared to the solute.
Soluble: Describes substances (usually solids) that can dissolve in a particular solvent to form a solution.
Insoluble: Describes substances (usually solids) that cannot dissolve in a particular solvent. When mixed, they may create a cloudy mixture or settle at the bottom.

When a solute dissolves in a solvent, the resulting solution is clear (transparent), meaning light can pass through without significant scattering.
The total mass of a solution is the sum of the masses of the solute and the solvent: $mass<em>{solution} = mass</em>{solvent} + mass_{solute}$ . This principle adheres to the law of conservation of mass.

$SOLUTE + SOLVENT = SOLUTION$

Water is the most common solvent due to its widespread availability, low cost, non-toxicity, and ability to dissolve many polar and ionic solutes.
Other liquids like white spirit, ethanol, acetone, and chloroform can also act as solvents, each effective for different types of solutes. For example, ethanol is used in many medicinal tinctures, while acetone is a common nail polish remover.
Solutes insoluble in water might be soluble in other solvents. The choice of solvent depends on the chemical properties of the solute.

When adding solute to a solvent, a point is reached where no more solute will dissolve at a given temperature. This is a saturated solution, representing an equilibrium state.
To dissolve more solute in a saturated solution, more solvent can be added, or the temperature can be increased, as solubility often increases with temperature. Alternatively, changing the pressure can also affect solubility, especially for gaseous solutes.

Mixtures can be separated using various methods, each suited for different types of mixtures based on their physical and chemical properties.

Used to Separate: Solid particles that do not dissolve in a liquid from the liquid. This method relies on the difference in particle size.
Apparatus Used: Filtration apparatus (e.g., filter paper and funnel, Buchner funnel with vacuum).
Examples:
- Tea leaves from tea.
- Sand from a mixture of sand and water.

Used to Separate: Dissolved substances from a solution by vaporizing the solvent.
Examples:
- Salt from salt solution. The water evaporates, leaving the salt behind.

Used to Separate:
- The liquid from a dissolved solid in a solution.
- One liquid from a mixture of liquids with different boiling points.
Apparatus: Includes a heat source, distillation flask, Liebig condenser, thermometer, and receiving flask. Water flows in and out of the condenser to facilitate condensation.
Examples:
- Water from salt solution.
- Alcohol from a mixture of alcohol and water. This is used in the production of spirits.
- The process involves heating the solution, collecting the vapor, and condensing it back into a liquid. The component with the lower boiling point vaporizes first and is collected separately.