AQA GCSE Combined Science: Synergy — Paper 3 (Physical Sciences, Foundation Tier)

Total marks: 100 · Duration: 105 minutes · Tier: Foundation

Instructions to candidates

• Answer all questions in the spaces provided.
• You are expected to use a calculator where appropriate.
• This paper assesses Physical Sciences: atomic structure and the periodic table, bonding, chemical reactions, and energy changes.
• A periodic table is provided.
• The maximum mark for this paper is 100. The marks for each question are shown in brackets.

Paper

Section A — Multiple Choice (10 marks)

For each question, choose the one correct answer.

1. The relative charge of a proton is… (1 mark) A) −1 B) 0 C) +1 D) +2

2. Most of the mass of an atom is found in the… (1 mark) A) electrons B) nucleus C) shells D) surface

3. Group 0 elements are called the… (1 mark) A) alkali metals B) halogens C) noble gases D) transition metals

4. Ionic bonding involves the… (1 mark) A) sharing of electrons B) transfer of electrons C) transfer of protons D) sharing of neutrons

5. The pH of a neutral solution is… (1 mark) A) 0 B) 7 C) 10 D) 14

6. A reaction that transfers energy to the surroundings is… (1 mark) A) endothermic B) exothermic C) neutral D) reversible only

7. Adding a catalyst to a reaction will… (1 mark) A) slow it down B) speed it up C) stop it D) cool it

8. When acids react with metals they produce a salt and… (1 mark) A) oxygen B) hydrogen C) chlorine D) water

9. The relative formula mass of O₂ (Ar O = 16) is… (1 mark) A) 8 B) 16 C) 32 D) 64

10. Increasing the surface area of a solid reactant makes the rate… (1 mark) A) slower B) faster C) unchanged D) zero

Section B — Structured Questions (90 marks)

11. This question is about atomic structure. (12 marks) (a) Name the three sub-atomic particles and give the relative charge of each. (6 marks) (b) An atom is written $^{23}_{11}\text{Na}$. State the number of protons, neutrons and electrons. (3 marks) (c) Explain why an atom has no overall charge. (2 marks) (d) What does the period number tell you about an atom? (1 mark)

12. The periodic table organises the elements. (12 marks) (a) State how the elements are ordered in the modern periodic table. (1 mark) (b) Explain why elements in the same group have similar chemical properties. (2 marks) (c) Describe what you would see when sodium reacts with water. (3 marks) (d) Explain the trend in reactivity down Group 1. (2 marks) (e) Describe a displacement reaction between chlorine and potassium bromide. (2 marks) (f) Give two properties of transition metals. (2 marks)

13. Substances are held together by bonds. (13 marks) (a) Describe how an ionic bond forms between a metal and a non-metal. (3 marks) (b) Explain why ionic compounds have high melting points. (2 marks) (c) Describe what is shared in a covalent bond. (2 marks) (d) Explain why simple molecular substances have low boiling points. (2 marks) (e) Explain why metals conduct electricity. (2 marks) (f) Give one use of graphite that depends on its ability to conduct, and explain why it conducts. (2 marks)

14. Acids take part in many reactions. (12 marks) (a) Complete: acid + metal → salt + __________ (1 mark) (b) Name the salt made from hydrochloric acid and sodium hydroxide. (1 mark) (c) Describe how to measure the pH of a solution using universal indicator. (2 marks) (d) Describe how to make pure, dry copper sulfate crystals from copper oxide and sulfuric acid. (4 marks) (e) Describe neutralisation in terms of H⁺ and OH⁻ ions. (2 marks) (f) During electrolysis of molten lead bromide, name the products at the cathode and the anode. (2 marks)

15. Chemists work out amounts of substances. (12 marks) (a) Calculate the relative formula mass of calcium carbonate, CaCO₃ (Ar: Ca = 40, C = 12, O = 16). (2 marks) (b) State the law of conservation of mass. (1 mark) (c) When magnesium burns its mass increases. Explain why. (2 marks) (d) Balance the equation: __ Mg + O₂ → __ MgO (2 marks) (e) Describe the test, and result, for hydrogen gas. (2 marks) (f) Describe the test, and result, for carbon dioxide gas. (2 marks) (g) Calculate the relative formula mass of water, H₂O (Ar: H = 1, O = 16). (1 mark)

16. Chemical reactions involve energy changes. (11 marks) (a) Define an exothermic reaction. (1 mark) (b) Define an endothermic reaction. (1 mark) (c) Give one everyday use of an exothermic reaction and one of an endothermic reaction. (2 marks) (d) On a reaction profile for an exothermic reaction, are the products higher or lower in energy than the reactants? (1 mark) (e) Define activation energy. (1 mark) (f) A student measured the temperature change when a metal reacted with acid. Describe how they could make the results reliable. (4 marks) (g) Is breaking bonds endothermic or exothermic? (1 mark)

17. Reactions happen at different rates. (12 marks) (a) What is a catalyst? (2 marks) (b) Use collision theory to explain why increasing the temperature increases the rate. (3 marks) (c) Explain why powdered solids react faster than large lumps. (2 marks) (d) Explain why increasing the concentration increases the rate. (2 marks) (e) Describe two ways to measure the rate of a reaction that produces a gas. (2 marks) (f) State the effect of a catalyst on the activation energy. (1 mark)

18. Extended response. (6 marks) A student has three metals: magnesium, zinc and copper. Describe how they could use reactions with dilute acid to place the metals in order of reactivity, and state the results they would expect.