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Copper oxide, CuO, is heated with carbon, C. Copper, Cu, and carbon dioxide, CO 2 , are made as shown in the equation: 2CuO + C 2Cu + CO 2 This reaction is an example of reduction. Use the equation to explain what reduction means.
See it on the paper →Explain how the equation shows that copper oxide, CuO, is reduced.
See it on the paper →Look at this ionic half-equation. Al 3+ + 3e – Al State if this reaction is an example of oxidation or reduction. Explain your answer.
See it on the paper →In stage 2, iron( III ) ions are reduced to iron atoms. Explain, in terms of electrons, why this is a reduction reaction.
See it on the paper →Complete and balance the half equation for the reaction in 5(b)(ii). + Fe
See it on the paper →In the blast furnace iron( III ) ions, Fe 3+ , are changed into iron. The balanced half-equation is shown. Fe 3+ + 3e – Fe Iron( III ) ions gain electrons. State the name of the process when electrons are gained.
See it on the paper →The meaning of reduction was usually correct and explained as the loss of oxygen or the gain of electrons.
— Examiner report, October/November 2022, 0654/41 Q11(a) (Cambridge)
A reference to a loss of oxygen was required to correctly answer this question.
— Examiner report, May/June 2022, 0654/33 Q5(c)(i) (Cambridge)
Those who knew that the discharge of aluminium ions is reduction explained that it involves the gain of electrons.
— Examiner report, May/June 2022, 0654/43 Q5(d) (Cambridge)
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