Separating Mixtures Quiz

Study Notes

Displacement of Water

Used to collect gases that are similar in density to air and are insoluble or slightly soluble in water.
Gas syringes are versatile, capable of collecting gases of various densities from chemical reactions.

Methods of Separation

Physical methods separate mixtures without chemical reactions to yield pure substances.

Separation Techniques for Mixtures

Solid-Solid: Techniques include magnetic attraction, sieving, and using suitable solvents.
Solid-Liquid: Techniques involve filtration, evaporation to dryness, and crystallisation.
Liquid-Liquid: Methods include simple distillation and fractional distillation.

Chromatography

Solvent acts as the mobile phase; chromatography paper serves as the stationary phase.
Results on chromatography paper called chromatogram:
- Number of spots indicates the quantity of substances in the sample.
- Horizontally aligned spots signify identical substances.
- A single spot implies a pure substance; multiple spots indicate a mixture.
- Matching spots horizontally suggests a possible sample source.

Examples in Chromatography

Sample P contains three substances; Q and S contain two substances each; R is a pure substance.
Matched spots (a and g; b and h) identify similarities in substances.
R is confirmed as a pure sample, while P, Q, and S are mixtures.

Separating Solid-Solid Mixtures

Magnetic Attraction: Utilizes magnets to extract magnetic substances (e.g., iron filings from sulfur).
Sieving: Relies on particle size; smaller particles pass through sieves, leaving larger particles behind (e.g., fine sugar from coarse salt).
Using Suitable Solvent: Dissolves one component while leaving others insoluble (e.g., salt in water, no effect on sand).

Separating Solid-Liquid Mixtures

Simple Distillation: Two state changes, boiling (liquid to gas) followed by condensation (gas to liquid).
Filtration:
- Residue: Insoluble solid on filter paper.
- Filtrate: Solution collected post-filtration.

Evaporation to Dryness

Designed to obtain heat-stable soluble solids (e.g., sodium chloride).
Converts NaCl in solution to dry NaCl upon heating.

Crystallisation

Suitable for heat-sensitive soluble solids (e.g., copper(II) chloride).
Heating causes saturation, followed by cooling for solid crystallisation.

Simple Distillation Setup

Thermometer's bulb positioned near the condenser to measure vapor boiling point accurately.
Boiling chips prevent bumping during boiling.
A conical flask ensures minimal loss of distillate.
Water flows counter-current to vapor flow to maintain cold surfaces for effective condensation.

Key Distillation Facts

Constant temperature during distillation until the entire substance is vaporized.
Condensed vapor collects in the receiving flask as distillate.

Description

Test your knowledge on the various methods of separating mixtures, including physical methods and gas collection techniques. This quiz will cover principles such as displacement of water and the use of gas syringes. Enhance your understanding of the properties of gases and their behavior during separation processes.