Experimental Chemistry Flashcards
What are the factors to choose the method of gas collection?
- Solubility of the gas in water
- Density of the gas compared to air
What are the methods to collect gas?
- displacement of water
- downward delivery
- upward delivery
When do we use displacement of water?
When the gas is slightly soluble/insoluble in water
When do we use upward delivery?
When the gas is less dense than air
When do we use downward delivery?
When the gas is denser than air
What are the apparatus for measuring volumes?
- Measuring cylinder (0.5cm3)
- Pipette (25.0cm3)
- Burette (0.05cm3)
Collection of Gases
What are the Solid-Solid Mixtures?
- sublimation
- magnetic attraction
What are the Solid-Liquid Mixtures?
- filtration
- evaporation to dryness
- crystallisation
- simple distillation
What are the Liquid-Liquid Mixtures?
- separating funnel
- fractional distillation
Sublimation
It is used to separate a mixture of solids in which only one of them sublimes. It skips being a liquid.
Filtration
It is used to separate an insoluble solid from a liquid. There will be a Filtrate and a Residue.
Evaporation to Dryness
It is used to separate a soluble solid from a solution by heating the solution to dryness. It can only be used if the solid is heat-stable.
Crystallisation
It used to separate a soluble solid from a solution. It can be used if the solid is not heat-stable.
What are the steps to Crystallisation?
- Heat the solution until saturated.
- Allow the solution to cool and crystallise.
- Filter to obtain the crystals.
- Dry the crystals between two sheets of filter paper.
Simple Distillation
It is used to separate a pure liquid from a solution.
Simple Distillation
It is used to separate a pure liquid from a solution.
Fractional Distillation
It is used to separate a mixture of miscible liquids with different boiling points.
