Chapter 5 · ICSE Class 6 Chemistry (Selina Concise)

Pure Substances and Mixtures, Separation of Mixtures

Distinguish pure substances from mixtures, and learn methods for separating mixtures like filtration and evaporation.

🧫 Chapter 5

Pure substances compared with mixtures, and the filtration separation method A pure substance shown as identical particles, a mixture shown as different particles combined, and a funnel with filter paper illustrating filtration as a separation method Pure Substance Mixture
5.1

Pure Substances vs Mixtures

A pure substance has a fixed composition (like an element or compound). A mixture contains two or more substances that are not chemically combined and can vary in proportion.

1

Is salt water a pure substance or a mixture?

A mixture, since the amount of salt can vary and it's not chemically bonded with the water

2

Is distilled water a pure substance or a mixture?

A pure substance

5.2

Methods of Separating Mixtures

Filtration separates insoluble solids from liquids. Evaporation separates a dissolved solid from a liquid by evaporating the liquid. Sieving separates particles of different sizes.

1

How would you separate sand from water?

Filtration

2

How would you recover salt from salt water?

Evaporation — heating the water until it evaporates, leaving the salt behind

Practice

Exercises

1. What is the difference between a pure substance and a mixture?

2. Which method would separate stones from rice?

3. Which method would separate salt dissolved in water?

4. Which method would separate sand from water?

5. Is air a pure substance or a mixture?

Next chapter — Air and Atmosphere 💨 →