CAIE IGCSE Chemistry (0620) Alternative to Practical Review

A comprehensive set of vocabulary flashcards covering the major concepts, apparatus, chemical tests, and experimental procedures from the CAIE IGCSE Chemistry Alternative to Practical syllabus.

Gas Syringe

Apparatus used to collect and measure the volume of a gas produced in a reaction.

Measuring Cylinder

A piece of laboratory equipment used to measure the volume of a liquid, though less accurate than a burette.

Independent Variable

The variable in an experiment that is intentionally changed by the investigator.

Dependent Variable

The variable in an experiment that is measured to observe the effect of the changes.

Control Variable

The variables that are kept the same throughout an investigation to ensure a fair test.

Pestle and Mortar

Instruments used to crush large lumps of a solid into a powder to increase surface area.

Successful Collisions

Collisions between particles that result in a chemical reaction; increasing concentration increases their frequency.

Limiting Reactant

The substance in a chemical reaction that is completely consumed first, determining the total amount of product formed.

Stationary Phase

In chromatography, the material (e.g., filter paper) on which the separation of substances takes place.

Mobile Phase

In chromatography, the mixture to be separated dissolved in a solvent (e.g., water or ethanol) that moves through the stationary phase.

$$Rf \text{ Value}$$

A ratio used to identify substances in chromatography, calculated as $\frac{\text{Distance moved by solute}}{\text{Distance moved by solvent}}$.

Locating Agent

A substance sprayed onto a dry chromatogram to make colorless substances visible.

Residue

The insoluble solid material left in the filter paper after the filtration process.

Filtrate

The liquid or solution that passes through the filter paper during filtration.

Crystallization

A separation technique where some solvent is evaporated from a solution and it is left to cool, causing solute crystals to form.

Simple Distillation

A method used to separate a solvent from a solution or an impure liquid by boiling and then condensing the vapor.

Fractional Distillation

A technique used to separate a mixture of liquids with different boiling points using a fractionating column.

End Point

The point in a titration where the indicator changes color, signaling that the reaction is complete.

Thymolphthalein

An indicator that is colorless in acidic solutions and blue in alkaline solutions.

Precipitation

An experiment type where two soluble salt solutions are mixed to produce an insoluble salt and a soluble salt.

Methyl Orange

An indicator that is red in acid and yellow in alkaline solutions.

Transition Metal Solid

A solid identified in lab tests by having a characteristic color rather than being white.

Flame Test: Lithium

A test resulting in a red flame when a sample is held in a blue Bunsen burner flame.

Flame Test: Potassium

A test resulting in a lilac flame when a sample is held in a blue Bunsen burner flame.

Flame Test: Barium

A test resulting in a light green flame when a sample is held in a blue Bunsen burner flame.

Cation Test: Aluminum ($Al^{3+}$)

Results in a white precipitate with sodium hydroxide that is soluble in excess, giving a colorless solution.

Anion Test: Carbonate ($CO_3^{2-}$)

Adding dilute nitric acid causes effervescence, and the gas produced turns limewater cloudy.

Anion Test: Sulfate ($SO_4^{2-}$)

Adding nitric acid followed by aqueous barium nitrate produces a white precipitate.

Gas Test: Oxygen ($O_2$)

A test where a glowing splint is placed in the gas and the splint relights.

Gas Test: Hydrogen ($H_2$)

A test where a lighted splint is placed in the gas, resulting in a 'squeaky pop' sound.

Gas Test: Chlorine ($Cl_2$)

A test where the gas bleaches damp red or blue litmus paper.

Test for Alkenes

Adding bromine water which changes from orange to colorless if the substance is present.

Anhydrous Cobalt (II) Chloride

A substance used to test for water, which turns from blue to pink in its presence.

Burette

A graduated glass tube with a tap at one end, used for delivering known volumes of a liquid, more accurately than a measuring cylinder.

Water Bath

An apparatus used to heat flammable liquids (like ethanol) to avoid using a direct Bunsen burner flame.

Line of Best-fit

A single, thin, smooth straight line or curve drawn on a graph that reflects the general trend of the data points.

Downward Delivery

A method for collecting gases that are more dense than air, such as carbon dioxide or chlorine.