Humber Admissions Practice Test

What distinguishes a combustion reaction from other types of chemical reactions?

1. It occurs at room temperature.

2. It requires a catalyst.

3. It involves the reaction of a substance with oxygen.

4. It produces only liquid products.

The correct answer is: It involves the reaction of a substance with oxygen.

A combustion reaction is specifically characterized by the reaction of a substance, typically a hydrocarbon or another organic compound, with oxygen. This reaction is exothermic, meaning it releases heat, and usually produces carbon dioxide and water as byproducts. The defining feature of combustion is this interaction with oxygen, which is crucial for the process to occur, setting it apart from other types of chemical reactions that may not involve oxygen or that could involve different reactants and products. In contrast, combustion does not require conditions like room temperature or the presence of a catalyst, as combustion can occur at elevated temperatures when sufficient heat is provided to initiate the reaction. Additionally, while combustion can produce various states of products (gases, liquids, and solids), it does not exclusively yield only liquid products, making this characteristic inaccurate for defining combustion reactions.