(a) What is meant by (i) elements (ii) compounds, and (iii) mixtures? Write down the names of two elements, two compounds and two mixtures.
(b) Classify the following into elements, compounds and mixtures :
Marble, Air, Gold, Brass, Sand, Diamond, Graphite, Petroleum, Common salt, Sea-water, Chalk
(a) What is meant by (i) elements (ii) compounds, and (iii) mixtures? Write down the names of two elements, two compounds and two mixtures.
(b) Classify the following into elements, compounds and mixtures :
Marble, Air, Gold, Brass, Sand, Diamond, Graphite, Petroleum, Common salt, Sea-water, Chalk
(a) Element: An element is the simplest form of a pure substance. All substance is ultimately made up of elements. An element may be defined as the simplest form of matter which cannot be decomposed by ordinary chemical means into simpler substances, nor it can be formed by the combination of other substances, or an element is a substance made up of atoms with the same atomic number.
Compound: A compound is a pure substance made up of elements. Thus, the gases oxygen and hydrogen combine to form water, a liquid compound. The solid potassium and the gases nitrogen and oxygen are found combined in potassium nitrate, a solid compound.
Mixture: most of the objects that we see around us are not pure substances ( like elements and compounds) but these are mixtures because they contain two or more substances in different proportions. A material obtained by mixing two or more substances ( elements or compounds) in any proportion is known as a mixture.
Elements :- Hydrogen(H) and Helium(He).
Compounds:- H2O(Water) and SO2(Sulphur Dioxide).
Mixtures:- Sugar in water and Soda in water.
(b)
Elements Compounds Mixtures - Gold
- Diamond
- Graphite
- Marble (Calcium carbonate)
- Common salt
- Water
- Chalk
- Air
- Brass
- Petroleum
- Seawater
- Sand
(a) Element: An element is the simplest form of a pure substance. All substance is ultimately made up of elements. An element may be defined as the simplest form of matter which cannot be decomposed by ordinary chemical means into simpler substances, nor it can be formed by the combination of other substances, or an element is a substance made up of atoms with the same atomic number.
Compound: A compound is a pure substance made up of elements. Thus, the gases oxygen and hydrogen combine to form water, a liquid compound. The solid potassium and the gases nitrogen and oxygen are found combined in potassium nitrate, a solid compound.
Mixture: most of the objects that we see around us are not pure substances ( like elements and compounds) but these are mixtures because they contain two or more substances in different proportions. A material obtained by mixing two or more substances ( elements or compounds) in any proportion is known as a mixture.
Elements :- Hydrogen(H) and Helium(He).
Compounds:- H2O(Water) and SO2(Sulphur Dioxide).
Mixtures:- Sugar in water and Soda in water.
(b)
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