Humber Admissions Practice Test

What characteristic differentiates a homogeneous mixture from a heterogeneous mixture?

1. Presence of different phases

2. Uniformity in composition

3. Different states of matter

4. Visibility of components

The correct answer is: Uniformity in composition

A homogeneous mixture is characterized by a uniformity in composition, meaning that its components are evenly distributed throughout the mixture and are not distinguishable from one another. For instance, when salt is dissolved in water, the resulting solution has the same composition throughout; any sample taken from it will have the same ratio of salt and water. This consistent composition is what distinguishes homogeneous mixtures from heterogeneous mixtures, where the components can often be identified as separate entities or phases. The presence of different phases, different states of matter, and visibility of components are relevant to understanding mixtures, but they do not capture the essence of what defines a homogeneous mixture. While heterogeneous mixtures display distinct layers or particles, inhomogeneous mixtures where various phases are evident can illustrate how some components remain separate; thereby reinforcing the idea of non-uniformity. Thus, the crucial characteristic that defines a homogeneous mixture is its uniform composition, which is not found in heterogeneous mixtures, where the varied components can be visually observed or physically separated.