Nature of Matter: Mixtures MCQs Quiz | Class 9

This interactive quiz covers Class IX Science (Code 086), Unit I: Matter – Its Nature and Behaviour. It specifically targets the topic Nature of Matter: Mixtures, including the concept of mixtures, their variable composition, and real-world examples. Test your understanding with these 10 questions, submit your answers to see your score, and download the detailed PDF answer sheet for your revision notes.

Understanding Mixtures in Matter

In the study of Matter and its Nature, a mixture is defined as a substance made by combining two or more different materials without any chemical reaction occurring between them. The substances involved in a mixture are known as constituents or components. Unlike compounds, mixtures do not have a fixed chemical formula.

Key Characteristics of Mixtures

  • Variable Composition: The components can be present in any proportion. For example, a mixture of sand and salt can have more sand or more salt; it remains a mixture regardless of the ratio.
  • Physical Change: Formation of a mixture is a physical change, not a chemical one. No new chemical bonds are formed.
  • Retention of Properties: Each constituent in a mixture retains its original physical and chemical properties. Sugar in water still tastes sweet; iron in a mixture with sulfur retains its magnetic property.
  • Separation: Components can be separated by physical methods such as filtration, evaporation, distillation, or magnetic separation.

Types of Mixtures

Mixtures are broadly classified into two categories based on the uniformity of their composition:

Feature Homogeneous Mixture Heterogeneous Mixture
Composition Uniform throughout. Non-uniform composition.
Visibility Components are not visible separately. Components are often visible to the naked eye.
Phase Single phase. Two or more phases.
Examples Air, Salt solution, Alloys (Brass). Sand and water, Oil and water, Soil.

Common Examples and Context

Air: Air is a classic homogeneous mixture of gases like nitrogen, oxygen, argon, and carbon dioxide.
Alloys: Though solid, alloys like brass (copper and zinc) are homogeneous mixtures because they show the properties of their constituents and have variable composition within certain limits.
Soil: Soil is a heterogeneous mixture containing sand, clay, decayed organic matter, pebbles, and air.

Quick Revision Notes

  • A mixture contains more than one pure substance.
  • Mixtures do not have fixed melting or boiling points; they melt or boil over a range of temperatures.
  • Energy is neither absorbed nor evolved in large amounts during the formation of a mixture.