Understanding Mixtures, Solutions, and Separation Techniques

Mixtures

A mixture is defined as a material system formed by combining two or more substances whose proportions can vary.

• Homogeneous mixtures: These consist of two or more components that cannot be distinguished visually.
• Heterogeneous mixtures: These are formed by two or more components that can be visually distinguished. They have different properties depending on the proportion of the sample taken.

Pure Substances

A pure substance is one in which, regardless of its state of aggregation, its properties are characteristic and allow differentiation from other substances.

• Chemical elements: These are pure substances that cannot be decomposed into simpler substances through normal physical and chemical processes.
• Compounds: These are pure substances made up of two or more elements and can be decomposed into these elements using chemical methods.

Solutions

Solutions are homogeneous and uniform mixtures of two or more components. The component in greater proportion is the solvent, and the other is the solute. Depending on the proportion of solvent and solute, there are three possibilities:

• Dilute solution: One in which the proportion of solute to solvent is very small.
• Concentrated solution: One in which the proportion of solute to solvent is high.
• Saturated solution: One that does not admit any more solute without adding more solvent at a determined temperature. The proportion between the solute and solvent is the maximum possible.

Separation Techniques

• Filtration: Used to separate the components of a heterogeneous mixture. The mixture is passed through a funnel with filter paper, which retains the particles to be separated.
• Settling: Used to separate mixtures of immiscible liquids with different densities or a solid deposited at the bottom of a container. The mixture is carefully poured into another container.
• Centrifugation: Used in the laboratory to separate the components of a heterogeneous mixture.
• Distillation: Used to separate homogeneous mixtures of miscible liquids with different boiling points, or to separate non-volatile solids dissolved in liquids. It is based on the fact that liquids boil at different temperatures.

Solubility

Solubility is defined as the maximum amount of solute that can be dissolved in a given amount of solvent. It is a fixed proportion for each pair of solute and solvent at a given temperature.