Ontario Grade 9 Science Class Practice Exam

What differentiates a mechanical (heterogeneous) mixture from other types of mixtures?

1. It has uniform composition throughout

2. Its components can be separated by physical means only

3. It is made of only one type of atom

4. You can distinguish between different types of matter in it

The correct answer is: You can distinguish between different types of matter in it

While all mixtures are composed of multiple substances, mechanical mixtures are unique in that they have visibly distinguishable components. This differs from a homogeneous mixture, where the components are evenly distributed and cannot be easily identified by sight. Heterogeneous mixtures also differ from pure substances, such as elements or compounds, which are composed of only one type of atom or molecule. Additionally, mechanical mixtures can be separated through physical means, such as using a sieve or magnet, while other mixtures, like solutions, require chemical reactions or other methods to separate their components.