GCSE 1.9 Chemical analysis : Elements compounds mixtures

What is a pure substance?

• A single element or compound not mixed with any other substance

• A mixture of several elements

• A solution of different compounds

• A combination of elements and mixtures

How can melting and boiling points be used in chemistry?

• To identify the color of a substance

• To distinguish pure substances from mixtures

• To measure the density of a substance

• To determine the pH level of a substance

Which of the following terms is NOT related to the separation of mixtures?

• Soluble

• Insoluble

• Solute

• Molecule

Which method is NOT used to separate mixtures?

• Filtration

• Crystallisation

• Paper chromatography

• Combustion

What is the mobile phase in paper chromatography?

• The paper

• The solvent

• The solute

• The residue

What is the purpose of calculating Rf values in paper chromatography?

• To measure the temperature

• To identify substances

• To determine the pH level

• To calculate the density

Simple distillation is used to obtain:

• pure water from sea water

• sand from sea water

• salt crystals

• pure water from a water and ethanol mixture

What color does lithium produce in a flame test?

• Crimson

• Yellow

• Lilac

• Brick red

What is used to test for water in chemistry?

• Hydrochloric acid

• Sodium hydroxide

• Anhydrous copper(II) sulfate

• Ethanol

What is an element?

• A substance that consists of only one type of atom and cannot be broken down into anything simpler by chemical means.

• A substance that consists of two or more different elements chemically bonded together.

• A mixture of different substances.

• A substance that can be broken down into simpler substances by physical means.