Key Concepts in Mixture Separation

This page introduces fundamental concepts related to mixtures and separation techniques. It defines key terms and provides an overview of chromatography, an important method of separating mixtures.

A mixture consists of two or more elements and/or compounds combined, with their chemical properties remaining unchanged. Separation techniques are physical processes used to isolate components of a mixture. The page also outlines the step-by-step procedure for performing paper chromatography.

Definition: A compound is two or more elements chemically combined.

Highlight: The chemical properties of each substance in a mixture remain unchanged, allowing for separation through physical processes.

Example: Copper sulfate reacting with iron (CuSO4 + Fe → FeSO4 + Cu) is an example of a chemical reaction, not a mixture separation.

The chromatography procedure step-by-step is outlined as follows:

1. Draw a pencil line near the bottom of the filter paper.
2. Place a small amount of ink on the line and set it in a beaker with solvent below the pencil line.
3. Cover the beaker to prevent evaporation.
4. Allow the solvent to travel up the paper, carrying the ink components.
5. Mark the solvent front and remove the paper when finished.

Vocabulary: Solvent front - The distance the solvent travels up the paper in chromatography.

Filtration and Crystallization Techniques

This page covers two additional separation techniques: filtration and crystallization. These methods are crucial for separating solids from liquids and obtaining pure crystals from solutions.

Filtration technique for separating mixtures:

1. Fold filter paper into a cone by folding it in half twice.
2. Place the filter paper into a filter funnel and position it on top of a conical flask.
3. Pour the mixture into the funnel.
4. The liquid passes through the filter paper, leaving the insoluble solid behind.

Example: Filtration can be used to separate sand from water, as sand is insoluble in water.

Crystallization procedure:

1. Pour the solution into an evaporating basin.
2. Gently heat the solution using a Bunsen burner to evaporate the solvent and concentrate the solution.
3. Remove the basin from heat when crystals start to form.
4. Allow the solution to cool, allowing the soluble salt to crystallize.
5. Filter the crystals from the remaining solution and let them dry.

Highlight: When heating solids, it's important to note that they can expand. Using a water bath can provide more controlled heating for sensitive procedures.

Vocabulary: Evaporation - The process of a liquid turning into a vapor, used here to concentrate solutions for crystallization.

These separation techniques are essential tools for chemists and students alike, allowing for the purification of substances and the isolation of desired components from mixtures.