Chemistry Paper 6 Final Revision: Separation Methods and Lab Techniques

Vocabulary and concepts for Chemistry Paper 6 revision, covering laboratory apparatus, separation methods, and chemical tests for ions and gases.

Solubility

The ability of a solid solute to dissolve in a liquid.

Miscibility

A term used specifically when talking about the solubility of liquid solutes.

Filtration

A separation method for a solid insoluble in a liquid, using a filter paper, funnel, and conical flask.

Residue

The solid collected on the filter paper during the filtration process.

Filtrate

The liquid that passes through the filter paper into the conical flask during filtration.

Separating Funnel

A piece of apparatus used to separate immiscible liquids (like Kerosene and Water) based on their density, controlled by a stopcock.

Crystallization

A separation method used to obtain a solid soluble in a liquid by heating the solution to evaporate most solvent and allowing it to cool into pure crystals.

Simple Distillation

A method used to obtain the liquid from a solution where a solid is soluble in that liquid.

Condenser

A piece of lab equipment that cools down vapor to turn it back into a liquid (distillate).

Fractional Distillation

A separation method used for miscible liquids using a fractionating column.

Fractionating Column

Its function is to prevent the liquid that didn't reach the boiling point from passing to the condenser during fractional distillation.

Chromatography Baseline

A line drawn in pencil (graphite) on chromatography paper; pencil is used because graphite is insoluble in water while ink is soluble and would run.

Organic Solvents

Solvents such as Ethanol or Propanol used in chromatography if the dyes are insoluble in water.

Solvent Level (Chromatography)

Must be below the baseline to prevent the spots from dissolving directly into the solvent.

Bung

A laboratory tool used to prevent gas from escaping a conical flask or boiling tube.

Mortar & Pestle

Tools used for crushing large lumps of solid materials into smaller pieces or powder.

White Tile

A tool used in experiments (like titrations) to see color changes accurately.

Burette

A scaled laboratory tool used for accurate volume delivery; it reads to 1 decimal place (e.g., $0.0\,cm^{3}$).

Downward Delivery

A method for collecting gases denser than air, such as $Cl_{2}$, $HCl$, $CO_{2}$, $SO_{2}$, and $NO_{2}$.

Upward Delivery

A method for collecting gases less dense than air, such as $H_{2}$ and $NH_{3}$.

Collection Over Water

A method for collecting gases that are insoluble in water, such as $CO_{2}$ and $SO_{2}$.

Polystyrene Cup

An insulator used as an alternative to glass beakers in temperature change experiments to prevent heat loss.

Water Bath

Used to heat flammable substances like alcohol to avoid using a Bunsen burner directly.

Fume Cupboard

A safety ventilation device used when experiments release toxic gases like $Cl_{2}$, $Br_{2}$, $F_{2}$, $I_{2}$, $SO_{2}$, or $NO_{2}$.

Cations

Positive ions, tested using Aqueous Sodium Hydroxide ($NaOH$) and Aqueous Ammonia ($NH_{3}OH$).

Anions

Negative ions, each having its own specific chemical test.

Halides

Anions including Chloride ($Cl^{-1}$), Bromide ($Br^{-1}$), and Iodide ($I^{-1}$), tested by acidifying with dilute nitric acid followed by silver nitrate.

Zinc ($Zn^{+2}$) Test

Forms a white precipitate that is soluble in excess Aqueous Sodium Hydroxide and Aqueous Ammonia, giving a colorless solution.

Iron (III) ($Fe^{+3}$) Test

Forms a red-brown precipitate that is insoluble in excess Aqueous Sodium Hydroxide and Aqueous Ammonia.

Copper (II) ($Cu^{+2}$) Test

Forms a light blue precipitate; insoluble in excess Sodium Hydroxide, but soluble in excess Ammonia.

Carbonate ($CO_{3}^{2-}$) Test

Acidify with dilute acid to produce effervescence and Carbon dioxide.

Sulfate ($SO_{4}^{2-}$) Test

Acidify and add aqueous Barium Nitrate to produce a white precipitate.

Ammonia Gas Test

Damp Red Litmus paper turns blue.

Chlorine Gas Test

Damp litmus paper bleaches.

Hydrogen Gas Test

A lighted splint produces a 'pop' sound.

Oxygen Gas Test

A glowing splint relights.

Sulfur Dioxide Gas Test

Acidified aqueous potassium manganate (VII) turns from purple to colorless.

Carbon Dioxide Gas Test

Limewater turns milky.

Anhydrous Copper Sulfate

A chemical test for water that changes color from white to blue.

Anhydrous Cobalt Chloride

A chemical test for water that changes color from blue to pink.

Flame Test: Sodium

Produces a yellow flame.

Flame Test: Potassium

Produces a lilac flame.

Flame Test: Lithium

Produces a red flame.

Flame Test: Copper

Produces a blue-green flame.

Calcium Oxide

A drying agent specifically used for drying Ammonia gas.

Gas Syringe

A tool used to measure the volume of gas produced in a reaction.