Question 1: Define oxidation in terms of electron transfer.

Answer: Oxidation is the loss of electrons by a substance during a chemical reaction.

Question 2: Explain the process of reduction in oxidation-reduction reactions.

Answer: Reduction is the gain of electrons by a substance during a chemical reaction.

Question 3: In a reaction where zinc metal reacts with copper sulphate solution, which substance is oxidised and which is reduced?

Answer: Zinc is oxidised, and copper is reduced.

Question 4: Describe the mechanism of electron transfer during oxidation and reduction.

Answer: Oxidation involves the loss of electrons from a substance, increasing its oxidation state. Reduction involves the gain of electrons, decreasing the oxidation state. Electrons are transferred from the oxidised species to the reduced species, often via an electron transfer mechanism facilitated by chemical bonds or an electron transport chain.

Question 1: Calculate the oxidation state of sulphur in sulphuric acid (H₂SO₄).

Answer: The oxidation state of sulphur in H₂SO₄ is +6.

Question 2: A piece of zinc metal (Zn) reacts with 50 mL of 0.1 mol/dm³ copper sulphate solution. How many moles of zinc are needed to fully react if the reaction is: Zn + CuSO₄ → ZnSO₄ + Cu? Show your calculations.

Answer: 0.005 mol of zinc is required, calculated using molar ratios and concentration data.

Question 1: Outline the key steps in conducting an experiment to compare the reactivity of aluminium, zinc, and iron with dilute acids.

Answer: The experiment involves preparing samples of each metal, adding dilute acid, observing the rate of hydrogen gas formation, and recording observations. Variables include type of metal (independent), reaction time (dependent), and acid concentration (controlled). Safety measures include wearing goggles, gloves, and working in a well-ventilated area to handle acids and gases safely.

Question 1: A series of metals (Aluminium, Zinc, Iron, Copper) are tested for reactivity with dilute hydrochloric acid. The reaction times observed are: Aluminium - 30 seconds, Zinc - 45 seconds, Iron - 90 seconds, Copper - no reaction after 10 minutes. What does this data suggest about their relative reactivity?

Answer: The data suggests Aluminium is most reactive, followed by Zinc, then Iron, with Copper being least reactive or unreactive under these conditions.

Question 1: Explain how the process of corrosion is an example of oxidation. Include in your answer the role of oxygen and moisture, and suggest two methods to prevent corrosion of iron structures.

Answer: Corrosion of iron is an oxidation process where iron reacts with oxygen in the presence of moisture to form iron oxide (rust). Oxygen acts as an oxidising agent, accepting electrons from iron. Prevention methods include applying protective coatings (paint or oil) and galvanising (coating with a sacrificial metal like zinc).