Science (086) — AI-generated practice question

(i) The substance formed when magnesium ribbon burns in air is magnesium oxide (MgO).

$$\text{Magnesium} + \text{Oxygen} \rightarrow \text{Magnesium oxide}$$

(ii) This is a chemical change, because a new substance (magnesium oxide) is formed which has different properties from the original magnesium ribbon, and the change cannot be reversed.

Source: Chapter 1, Section 1.1 Chemical Equations

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• Part (i) is a direct recall fact — always name the product and write the word equation if space allows.
• Part (ii) needs a reason: the key indicator of a chemical change is formation of a new substance with different properties. Examiners also accept "irreversible change" as a valid reason. Avoid vague answers like "it looks different."