2024/2025 Edexcel IGCSE Chemistry - Paper 1: Revision Questions with Merged Answers

▪ Potassium manganate (VII) and water (purple colour spreads), ammonia and hydrogen chloride (white ring forms closer to hydrogen chloride), bromine gas and air (brown bromine gas diffuses) - Ans .3 experiments to show diffusion ▪ 4OH- = O2 + 2H2O + 4E- - Ans .Half equation for hydroxide ions ▪ Moves slowly (on the surface), fizzes, eventually disappears - Ans .Lithium with water - observations ▪ Moves quickly (on the surface), fizzes rapidly, may ignite - Ans .Sodium with water - observations ▪ Reacts vigorously, burns with a lilac flame, sometimes explodes - Ans .Potassium with water - observations ▪ Heat copper (in a tube and pass air over it) - Ans .Experiment to test the proportion of oxygen in air ▪ Pale blue - Ans .Sulfur flame colour ▪ Orange/yellow - Ans .Carbon flame colour ▪ Downward delivery (it is denser than air) - Ans .How to collect chlorine ▪ 2H2O + CaCO3 = CaCl2 + H2O + CO2 - Ans .How to make CO2 in a lab (equation) ▪ It is soluble in water - Ans .Why can CO2 be used in fizzy drinks? ▪ Platinum wire, dip in hydrochloric acid, hold in flame - Ans .Flame test wire to use + how to sterilise it ▪ So the gas can dissolve and make the colour change - Ans .Why does litmus paper need to be damp when testing a gas? ▪ Hydrochloric acid - Ans .Acid added to remove any impurities for the sulphate test ▪ Nitric acid - Ans .Acid added to remove any impurities for the halide test ▪ Bleaches damp litmus paper white - Ans .Test for chlorine ▪ A group of organic compounds that can all be represented by the same general formula - Ans .Homologous series ▪ Similar chemical properties, a trend in physical properties (boiling points, colour, viscosity) - Ans .Members of the same homologous series have... ▪ A group of atoms which are arranged or bonded in a particular way and which determine how an organic compound will react - Ans .Functional group ▪ Carbon to hydrogen bond - Ans .Alkane functional group ▪ Carbon double bond - Ans .Alkene functional group ▪ Hydroxide bond - Ans .Alcohol functional group ▪ Carbon - Ans .An organic compound is one that contains ▪ CnH2n+2 - Ans .Alkane general formula ▪ CnH2n - Ans .Alkene genera