AQA GCSE Combined Science: Trilogy — Chemistry Paper 1 (Foundation Tier)

Total marks: 70 · Duration: 75 minutes · Tier: Foundation

Instructions to candidates

• Answer all questions in the spaces provided.
• You are expected to use a calculator where appropriate.
• This paper covers Topics 8–12: Atomic Structure and the Periodic Table, Bonding, Quantitative Chemistry, Chemical Changes, and Energy Changes.
• A copy of the periodic table is provided.
• The maximum mark for this paper is 70. The marks for each question are shown in brackets.

Paper

Section A — Multiple Choice (5 marks)

For each question, choose the one correct answer.

1. What is the charge on a proton? (1 mark) A) +1 B) −1 C) 0 D) +2

2. Which group of the periodic table contains the noble gases? (1 mark) A) Group 1 B) Group 7 C) Group 0 D) Group 2

3. What is the pH of a neutral solution? (1 mark) A) 0 B) 7 C) 10 D) 14

4. An exothermic reaction is one that… (1 mark) A) takes in heat B) gives out heat C) has no energy change D) only happens when heated

5. Which particles are transferred when an ionic bond forms? (1 mark) A) Protons B) Neutrons C) Electrons D) Atoms

Section B — Structured Questions (65 marks)

6. This question is about the structure of the atom. (a) Name the three sub-atomic particles found in an atom. (3 marks) (b) Where in the atom are the electrons found? (1 mark) (c) An atom of sodium has the symbol $^{23}_{11}\text{Na}$. State the number of protons and the number of neutrons in this atom. (2 marks) (d) Sodium is in Group 1. How many electrons does a sodium atom have in its outer shell? (1 mark)

7. The periodic table arranges the elements. (a) Elements are arranged in order of increasing _____________. Choose the correct word. (1 mark) mass number / atomic (proton) number / number of neutrons (b) State one property of a typical metal. (1 mark) (c) Chlorine is in Group 7. Explain why chlorine and bromine have similar chemical properties. (2 marks) (d) Lithium reacts with water. Describe two things you would see. (2 marks)

8. Sodium chloride is an ionic compound. (a) Describe how a sodium atom and a chlorine atom form ions when they react. (3 marks) (b) Sodium chloride has a giant ionic lattice. Explain why it has a high melting point. (2 marks) (c) Explain why solid sodium chloride does not conduct electricity, but molten sodium chloride does. (2 marks)

9. A student burned magnesium in air to make magnesium oxide. magnesium + oxygen → magnesium oxide (a) The student measured 2.4 g of magnesium and made 4.0 g of magnesium oxide. Explain why the mass increased. (2 marks) (b) Balance this symbol equation: (1 mark) __ Mg + O₂ → __ MgO (c) State the law of conservation of mass. (1 mark) (d) Calculate the relative formula mass (Mr) of magnesium oxide, MgO. (Ar: Mg = 24, O = 16) (1 mark)

10. Acids react with several substances. (a) Complete the general equation: (1 mark) acid + metal → salt + __________ (b) Name the salt made when hydrochloric acid reacts with sodium hydroxide. (1 mark) (c) Describe how you could measure the pH of a solution using universal indicator. (2 marks) (d) A student adds excess copper oxide to warm sulfuric acid to make copper sulfate. Describe how they would obtain dry copper sulfate crystals from the mixture. (4 marks)

11. Energy changes happen in chemical reactions. (a) When ammonium nitrate dissolves, the temperature falls. Is this exothermic or endothermic? (1 mark) (b) Give one everyday use of an exothermic reaction. (1 mark) (c) A reaction profile is drawn for an exothermic reaction. State whether the products are at a higher or lower energy than the reactants. (1 mark)

12. Electrolysis can break down compounds. (a) What does the term electrolysis mean? (1 mark) (b) During the electrolysis of molten lead bromide, name the product formed at the negative electrode (cathode). (1 mark)

13. This question is about metals and reactivity. A student has three metals: magnesium, zinc and copper. Describe how the student could use reactions with dilute hydrochloric acid to place the three metals in order of reactivity, from most to least reactive. In your answer, describe what they would do and what results they would expect. (6 marks)

14. This question is about atoms, bonding and reactions. (a) Name the sub-atomic particle with no charge. (1 mark) (b) An atom of magnesium has the electronic structure 2,8,2. State the number of electrons in its outer shell. (1 mark) (c) Explain why argon (Group 0) is unreactive. (2 marks) (d) Balance the equation: __ H₂ + __ O₂ → __ H₂O (2 marks) (e) Calculate the relative formula mass (Mr) of carbon dioxide, CO₂ (Ar: C = 12, O = 16). (2 marks) (f) Describe how to make pure, dry copper sulfate crystals from copper oxide and dilute sulfuric acid. (4 marks) (g) Explain why an ionic compound conducts electricity when molten but not when solid. (2 marks) (h) Name the gas that produces a "squeaky pop" with a lighted splint. (1 mark) (i) Define an exothermic reaction. (1 mark) (j) State one safety precaution when heating a solution with a Bunsen burner. (1 mark) (k) Give one observation when magnesium reacts with dilute acid. (1 mark) (l) State the law of conservation of mass. (1 mark) (m) Name the type of bonding in sodium chloride. (1 mark) (n) State the charge on a sodium ion, Na⁺. (1 mark)