AQA GCSE Combined Science Trilogy - Chemistry - Paper 2 Revision Questions with Complete Solutions 2024/2025

pure substance - Ans .single element, compound or substance not mixed with another substance physical processes - Ans .mixtures can be separated by... simple distillation - Ans .evaporating water and condensing it in a separate container fractional distillation - Ans .evaporating liquids with different boiling points filtration - Ans .screening and sieving to remove solids chromatography - Ans .using a solvent to separate pigments so you can identify them crystallisation - Ans .evaporating a solution to a small volume and leaving it to cool to form crystals chemically bonded - Ans .a mixture is made from different substances that aren't... a mixture designed for a use - Ans .a formulation is... mixing components in carefully measured amounts - Ans .a formulation is made by... the solvent moves through the paper - Ans .in paper chromatography... different compounds to different distances depending on their attraction to the paper and solvent - Ans .chromatography carries... distance moved by compound ÷ distance moved by solvent - Ans .Rf value = single spot in all solvents - Ans .in chromatography, a pure compound produces a... damp blue litmus paper red and then bleaches it white - Ans .chlorine turns... glowing splint relight - Ans .oxygen gas test makes a... squeaky pop sound - Ans .hydrogen gas test makes a... limewater go cloudy - Ans .carbon dioxide gas test makes... warmth, shelter, food and transport - Ans .the Earth provides humans with... food, timber, clothing and fuels - Ans .natural resources along with agriculture give us... processes to make energy and materials - Ans .finite resources involve... there is only a certain amount of them - Ans .finite means... using the Earth's resources in a way that can continue in the future. - Ans .sustainable resources involves... meet the needs of people today without impacting on the needs of people in the future - Ans .sustainable development should... safe to drink - Ans .potable water is... dissolved salts and microbes - Ans