In this post, we will discuss about atoms and molecules. Law of chemical combination There are, in all, 5 laws of chemical combination. Here, only two of them, which contributed significantly towards the development of chemistry are described. What is the law of conservation of mass? The law of conservation of mass states that, “during […]
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Based on the chemical constitution, matter is classified into two kinds: Substances and Mixtures. Substances are further classified into elements and compounds. Elements What is an element? Element is the basic constituent of all matter. An element is the simplest form of matter, which can’t be split into simpler substances by any chemical or physical
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In this post, we will discuss about physical and chemical changes and their characteristics. What is a Physical change? A physical change may be defined as follows: A change in which only the physical properties of the substance get changed, while its chemical composition remain unchanged, is called a physical change. During a physical change,
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In this post we are discussing about solutions, colloids and suspensions for class 9. Solutions A lump of sugar when placed in water disappears and the water becomes sweet. Where is sugar gone? Why does the water taste sweet? The sugar placed in water gets dissolved in it but remain unchanged. This is an example
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In this post, we will discuss about matter and its classification. What is matter? Matter is the material of which the universe is composed. Matter may be defined as something that occupies space, have mass and offers resistance to any force applied on it. For ex: Air, Water, Ice, Milk, Oil, Petrol, etc. What are
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This post contains Question Answer of chapter Is Matter Around Us Pure including NCERT Exercise. 1. What is meant by a substance? Sol: A substance is a kind of matter that cannot be separated into other kinds of matter by any physical process. 2. List the point of difference between homogeneous and heterogeneous mixtures. Sol:
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This post contains Question Answer of chapter Matter in Our Surroundings including NCERT Exercise. 1. Which of these are matter: Chair, air, love, smell, hate, almonds, thought, cold, cold drink, smell of perfume? Sol: The following are matter: chair, air, almonds, cold drink, smell of perfume. 2. Give reasons for the following observation: The smell
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Humidity is the amount of water vapour in the air. The humidity of air is defined as the amount of water vapour which is present in one unit volume of the air. It is measured in the units of gram per cubic meter. What is absolute humidity? The maximum limit of the water vapour which
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In this post, we will discuss about evaporation and the factor affecting its rate of evaporation. What is Evaporation? Evaporation is generally defined as a process in which a liquid state changes into vapour state. Evaporation is a form of vaporisation that usually occurs on the surface of liquids and involves the change of the
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In this post we will discuss about latent heat and its two forms. Let’s start with a question. Why does the temperature remain constant during melting and boiling even when heat is being supplied to a substance continuously? This is so because the heat supplied to the substance is used up in overcoming the intermolecular
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