Gcse Aqa Chemistry Exam Questions (107 Terms) With Verified Definitions Updated 2024

What is a macromolecule? Give some examples {Ans: Macromolecules - are formed by giant covalent bonds, e.g. diamond, graphite, silicon dioxide etc...}What are the products of the electrolysis of sodium chloride, and what are they used for? {Ans: Hydrogen - margarine / Haber process Chlorine - swimming pools / cleaning products Sodium hydroxide - soap / paper}What are the melting and boiling points of covalent compounds like? Explain why this is {Ans: Covalent compounds have low melting and boiling points (are often gases) are there is no attraction between the molecules}What is an exothermic reaction? Give an example {Ans: A reaction which gives out energy (usually heat), e.g. combustion / respiration}Give 3 reasons why a reaction may not give the theoretical yield {Ans: The reaction may not go to completion because it is reversible Some of the produce may be lost when it is separated from the reaction mixture Some of the reactants may react in ways different to the expected reaction}What happens to the unused nitrogen and hydrogen? {Ans: Unused nitrogen and hydrogen are recycled}