Class 9 Science — Chapter 2: Is Matter Around Us Pure?

What you'll learn

• ▸Scientific Definition of Pure Substances and Mixtures
• ▸Homogeneous and Heterogeneous Mixtures
• ▸Solutions and Their Properties
• ▸Concentration of a Solution
• ▸Calculating Solution Concentration
• ▸Suspensions and Their Properties
• ▸Colloidal Solutions and Their Properties
• ▸Alloys as Solid Solutions

Chapter Summary

--- PAGE 1 --- Chapter 2 0964CH02 Is Matter Around Us Pure? How do we judge whether milk, ghee, butter, salt, spices, mineral water or juice that we buy from the market are pure? SALT EXTRA FREE FLOW IODISED SALT Pure Ghee Pure MILK Pure MILK Pure MILK Fig. 2.1: Some consumable items Have you ever noticed the word 'pure' written on the packs of these consumables? For a common person pure means having no adulteration. But, for a scientist all these things are actually mixtures of different substances and hence not pure. For example, milk is actually a mixture of water, fat, proteins, etc. When a scientist says that something is pure, it means that all the constituent particles of that substance are the same in their chemical nature. A pure substance consists of a single type of particle. In other words, a substance is a pure single form of matter. As we look around, we can see that most of the matter around us exists as mixtures of two or more pure components, for example, sea …

Practice Questions from this Chapter

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1. Define pure substances simply. Get Solution →
2. List common household mixtures. Get Solution →
3. Compare homogeneous and heterogeneous mixtures. Get Solution →
4. According to a scientist, what is a pure substance? Get Solution →
5. Which of the following is explicitly mentioned in the text as an example of a mixture? Get Solution →
6. What is the definition of a solution provided in the chapter? Get Solution →
7. A solution is made of two components. What are they called? Get Solution →
8. In a 'tincture of iodine', which is a solution of iodine in alcohol, what is the solute? Get Solution →

Did you know?

• 💡 Tap water contains dissolved minerals and gases, making it a mixture, not just H2O.
• 💡 Water is called the "universal solvent" because it can dissolve more substances than any other liquid.
• 💡 Your blood is a complex mixture containing plasma, red blood cells, white blood cells, and platelets.
• 💡 Most gold jewelry is an alloy, mixed with metals like copper or silver to make it harder.
• 💡 Earth's atmosphere is a gaseous solution, primarily made of 78% nitrogen and 21% oxygen.

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