AFOQT Practice Test

What characterizes a synthesis reaction?

1. One substance breaks down into simpler substances

2. One element replaces another in a compound

3. Two or more substances combine to form a single product

4. A substance reacts with oxygen, releasing energy

The correct answer is: Two or more substances combine to form a single product

A synthesis reaction is defined by the combination of two or more reactants to create a single product. This process involves elements or simpler compounds merging to form a more complex substance. The essence of a synthesis reaction is cohesively bringing together different entities to yield a new compound, illustrating a clear transformation in the reaction. In contrast, the other options highlight different types of reactions: the first option describes a decomposition reaction where one compound breaks down into simpler components, the second refers to a single replacement reaction where one element substitutes another in a compound, and the last pertains to combustion reactions where a substance reacts with oxygen. Thus, the correct identification of a synthesis reaction as the formation of a single product from multiple reactants is essential in understanding chemical processes.