Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What can be described as a mixture?

1. A single chemical compound

2. A solution that is chemically bonded

3. Two or more substances that are not chemically combined

4. A pure substance with consistent properties

The correct answer is: Two or more substances that are not chemically combined

A mixture is defined as a combination of two or more substances that retain their individual properties and are not chemically bonded together. This characteristic is crucial because, in a mixture, each component maintains its own chemical identity and can be present in varying proportions. For instance, in a salad, the lettuce, tomatoes, and cucumbers can all be identified separately and do not undergo a chemical change when mixed together. The other concepts provided are distinct from the definition of a mixture. A single chemical compound is a pure substance made up of only one type of molecule, which lacks the diversity found in mixtures. A solution that is chemically bonded does not capture the essence of a mixture, as it implies a homogeneous combination where the components are fully integrated at a molecular level, rather than remaining as separate entities. Lastly, a pure substance with consistent properties refers to materials that have uniform composition and characteristics, which starkly contrasts with the variability found in mixtures where the ratios and types of substances can vary.