AQA · GCSE · Chemistry

Chemical changes

05.3 · 1 mark Negative-electrode product in aqueous electrolysis Name the product formed at the negative electrode when aqueous calcium chloride solution is electrolysed. 05.4 · 1 mark Positive-electrode half equation What is the half equation for the reaction at the positive electrode when aqueous calcium chloride solution is electrolysed?... 05.5 · 3 marks Explaining copper chromate ion migration Copper chromate solution contains the ions Cu²⁺ and CrO₄²⁻. Explain the results shown in Figure 5. 07.4 · 1 mark Ion ratio in magnetite The most common oxides of iron are Fe₂O₃ and Fe₃O₄. What is the ratio of the numbers of ions in Fe₃O₄? Tick one box. 09.1 · 2 marks Defining a weak acid Acids can be either weak or strong. What is meant by ‘a weak acid’? 09.2 · 2 marks Effect of dilution on acid pH Explain what happens to the pH of an acid as the acid is diluted with water. 09.3 · 3 marks Preparing an alkali for titration A student does a titration to find the volume of acid needed to neutralise an alkali. The student fills a burette with the acid....

AQA · GCSE · Chemistry

Energy changes

06.1 · 3 marks Ordering metals using cell voltages Write the symbols of the five metals in Table 3 in order of reactivity. Justify your answer. 06.2 · 6 marks Planning a chemical-cell concentration experiment The voltage produced by a chemical cell depends on the concentration of the electrolyte solution. Plan an experiment to... 08.2 · 1 mark Selecting an exothermic reaction profile Figure 8 shows four reaction profiles. Which is the correct reaction profile and labels for the reaction between propane and... 08.3 · 5 marks Calculating an unknown C—H bond energy Figure 9 shows the displayed formula equation for the reaction between propane and oxygen. The overall energy change of this...

AQA · GCSE · Chemistry

Bonding, structure, and the properties of matter

07.2 · 3 marks Atomic layers in iron alloys Pure iron is too soft for many uses. Explain why mixing iron with other metals makes alloys which are harder than pure iron. 09.5 · 3 marks Electron shielding and calcium reactivity A calcium atom is larger than a magnesium atom. Explain why calcium reacts more vigorously than magnesium with hydrochloric acid...

AQA · GCSE · Chemistry

Quantitative chemistry

07.3 · 1 mark Balancing iron and chlorine stoichiometry When iron reacts with chlorine, 0.12 mol of iron reacts with 0.18 mol of chlorine (Cl₂). Which is the correct equation for the... 07.5 · 3 marks Percentage iron by mass in magnetite Calculate the percentage (%) by mass of iron in Fe₃O₄. Relative atomic masses (Aᵣ): O = 16, Fe = 56. 07.6 · 5 marks Calculating carbon dioxide gas volume Fe₂O₃ reacts with carbon to produce carbon dioxide. Calculate the volume of carbon dioxide gas at room temperature and pressure... 09.4 · 2 marks Calculating hydrochloric acid titration volume The student titrated a solution containing 0.0045 moles of sodium hydroxide with 0.15 mol/dm³ hydrochloric acid. The equation... 01.5 · 4 marks Mean sodium ion concentration Calculate the mean concentration of sodium ions in the salt solution.

AQA · GCSE · Chemistry

Chemical analysis

01.1 · 2 marks Sodium ion flame test Describe a test to identify sodium ions. Give the result of the test. 01.2 · 2 marks Chloride ion precipitation test Describe a test to identify chloride ions. Give the result of the test.

AQA · GCSE · Chemistry

Using resources

01.3 · 1 mark Heating to constant mass Why did the student heat the evaporating dish and contents until the mass did not change? 01.4 · 1 mark Solid mass by subtraction How did the student calculate the mass of solid sodium chloride remaining after steps 1 to 5? Tick one box.

AQA · GCSE · Chemistry

The rate and extent of chemical change

02.1 · 1 mark Ammonia recycling in Haber process Pipe P links the condenser to the reactor. Why is the condenser linked to the reactor? Use Figure 1. 02.2 · 1 mark Haber process catalyst selection Which metal is used as a catalyst in this reaction?