Science (086) — AI-generated practice question

A reaction in which two or more substances combine to form a single new substance is called a combination reaction.

Example: Calcium oxide (quick lime) reacts with water to form calcium hydroxide (slaked lime):

$$\text{CaO}(s) + \text{H}_2\text{O}(l) \rightarrow \text{Ca(OH)}_2(aq) + \text{Heat}$$

This is used in everyday whitewashing of walls.

Source: Chapter 1 – Chemical Reactions and Equations, Section 1.2.1

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• 1 mark for the correct definition — must include "two or more substances" combining into "one/single product."
• 1 mark for the example — the equation (even in word form) with reactants and product named earns full credit. The CaO + H₂O → Ca(OH)₂ reaction is the textbook illustration, so use it confidently.
• Avoid writing a long explanation; the examiner checks for the definition keyword and a valid equation/example.