Mixtures

Introduction

In science, a mixture is a combination of two or more substances that are not chemically bonded together. Each substance in a mixture retains its own properties and can be separated by physical means.

Homogeneous Mixtures

Homogeneous mixtures are uniform throughout, with the same composition and properties in all parts. An example is a solution of salt dissolved in water.

Heterogeneous Mixtures

Heterogeneous mixtures have visibly different substances that are not evenly distributed. An example is a mixture of sand and iron filings.

Suspension

A suspension is a heterogeneous mixture where particles settle out if left undisturbed. For example, a mixture of water and sand.

Common Mistakes

• Confusing mixtures with compounds.
• Assuming all mixtures are homogeneous.

Key Points

• A mixture is a combination of two or more substances that are not chemically bonded.
• Homogeneous mixtures are uniform throughout, while heterogeneous mixtures have visibly different parts.
• Suspensions are heterogeneous mixtures where particles settle out over time.

Practice Questions

1. Explain the difference between homogeneous and heterogeneous mixtures.
2. Give an example of a suspension and explain why it is classified as a heterogeneous mixture.