Chemistry Paper 2 GCSE AQA Foundation Verified Solutions

Chemistry Paper 2 GCSE AQA Foundation Verified Solutions 1. What is the state of balance reached when a chemical reaction and its reverse reaction occur at the same rate? Answer: Equilibrium. 2. What is a substance that speeds up a chemical reaction without being consumed or altered? Answer: A catalyst. 3. What are the approximate percentages of gases in the Earth's atmosphere, respectively? Answer: Oxygen (20%), Nitrogen (79%), Water vapor (1%), and Carbon dioxide (<1%). 4. What is the equation for the process by which plants produce glucose and oxygen? Answer: Carbon dioxide + water → Oxygen + glucose. 5. Why do countries face challenges in reducing carbon dioxide emissions? Answer: Due to disagreements and limited resources. 6. What is the process of separating a mixture by passing it through a filter? Answer: Filtration. 7. How does electrolysis work, and what is its application? Answer: Electrolysis is a process that uses an electric current to drive a chemical reaction, often used to decompose water or produce hydrogen gas. 8. What is the process of purifying a liquid by heating and cooling it called? Answer: Distillation. 9. How can you separate a solution from its solvent to obtain pure crystals? Answer: By evaporating the solution to a smaller volume and allowing it to cool, resulting in crystallization. 10. What is the key difference between fuel and crude oil? Answer: Fuel is a compound, while crude oil is a mixture of many compounds. 11. How can you obtain drinking water from rivers and lakes? Answer: By desalination and sterilization processes. 12. Why does soot form during incomplete combustion reactions? Answer: Because there is insufficient oxygen to complete the combustion process. 13. How do you calculate the rate of a chemical reaction? Answer: By dividing the quantity of reactant used by the time taken. 14. What are the typical units of rate measurement in chemistry? Answer: Grams or volume in cubic centimeters (cm³). 15. What symbol indicates that a reaction is reversible? Answer: The arrow symbol (⇌) or double arrow symbol (⇆) indicates that a reaction is reversible. 16. Where do you typically find reactants and products in a chemical equation? Answer: Reactants are typically listed on the left side, while products are listed on the right side. 17. What is crude oil composed of primarily? Answer: Crude oil is primarily composed of hydrocarbons, which are molecules made up of hydrogen and carbon atoms only. 18. What type of hydrocarbons dominate crude oil composition? Answer: The majority of hydrocarbons in crude oil are alkanes. 19. Name four members of the alkane family: Methane, Propane, Ethane, Butane 20. What process involves breaking down larger hydrocarbons into smaller, more useful molecules, and under what conditions does it occur? Answer: Cracking occurs under high pressure and high temperature conditions, breaking