Name the technique(s) and briefly describe the procedure for separating each of the following mixtures into pure components: (a) table salt and pepper; (b) drinking water contaminated with soot; (c) crushed ice and crushed glass; (d) table sugar dissolved in ethanol; (e) two pigments (chlorophyll a and chlorophyll b) from spinach leaves.

Mixture separation techniques are used to divide a mixture—containing two or more components—into its pure components. Each technique leverages the unique properties of the components involved. For instance, if you have a mixture of table salt and pepper, you can use a combination of dissolution, filtration, and evaporation. First, dissolve the salt in water, leaving the pepper undissolved. Next, filter out the pepper. Finally, evaporate the water to retrieve the salt. This is just one example; different mixtures require different methods based on their individual properties. Examples of commonly used separation techniques include filtration, evaporation, and chromatography.

Filtration is a technique used to separate a solid from a liquid in which it is not dissolved. This method is especially useful when separating components based on particle size. To filter a mixture, you pour it through a filter material like filter paper or a sieve, which traps the solid particles and allows the liquid to pass through. For example, to clean drinking water contaminated with soot, you can filter the water through fine filter paper. The soot particles will be trapped in the paper, leaving clean water. Filtration is efficient and simple, making it a widely used separation technique in chemistry.

Evaporation is a process used to separate a soluble solid from a solvent. It involves heating the solution until the solvent evaporates, leaving the solid behind. This method works best when the solvent has a lower boiling point than the solute. For instance, to separate table sugar from ethanol, you heat the solution. Since ethanol has a lower boiling point, it evaporates first, leaving behind the sugar. This same principle can be applied in various chemical processes, making evaporation a versatile and crucial technique for separating mixtures.

Chromatography is a powerful technique for separating the components of a mixture based on their different affinities towards the stationary and mobile phases. The process starts with an extract applied onto chromatography paper before placing it in a suitable solvent. As the solvent rises through the paper, different components of the mixture travel at different speeds, leading to their separation. For example, to separate chlorophyll a and chlorophyll b from spinach leaves, you can extract the pigments using a solvent and apply the extract onto chromatography paper. Each pigment will move differently on the paper, providing a distinct separation. The ease and precision make chromatography valuable in biochemical analyses.

Solubility is a chemical property that describes the ability of a substance to dissolve in a solvent. It is crucial in determining the appropriate method for separating mixtures. For example, in the case of a mixture of table salt and pepper, the salt dissolves in water, whereas the pepper does not. By leveraging solubility - dissolving the salt in water and removing the undissolved pepper via filtration - we can effectively separate the two components. Understanding the solubility of various substances allows chemists to use the most effective separation technique for a given mixture, whether it’s for filtration, evaporation, or another method.