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प्रश्न
What is meant by H20 and 3H2O
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उत्तर
H20 represents one molecule of water. 3H20 represents 3 molecules of water.
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संबंधित प्रश्न
Tick the most appropriate answer.
How many times is a proton heavier than an electron?
- 1500
- 1800
- 1840
- none of these
Give Two Examples for Each of the Following: Non-metals
Why is it necessary to separate the constituents of a mixture.
Classify the following substances into elements and compounds
Mercury, sulphur, sugar, water, sand, gold, carbon, oxygen, alcohol, iron, marble, baking soda.
Give reason: Argon is filled in electric bulbs.
Match the Columns:
| Column A | Column B | ||
| (a) | Metals | (i) | Non-Reactive |
| (b) | Molecules | (ii) | Brittle |
| (c) | Non-Metals | (iii) | Lustrous |
| (d) | Noble Gases | (iv) | Smallest unit of Compound |
The important physical properties of substances are colour, odour, nature, density & solubility in water.
Name - a poisonous gas almost as heavy as air.
Match the statements in List I – 1 to 10 correct answers in List II-A to J.
| List I | LIst II | ||
| 1 | Fluorine and chlorine | A | Nitrogen |
| 2 | A diatomic molecule | B | Boron |
| 3 | A molecule containing the elements hydrogen and oxygen. | C | Reactants |
| 4 | A metalloid - showing properties of both metals and non-metals. | D | Chemical Formula |
| 5 | The term used for the substances which take part in the chemical reaction | E | Halogens |
| 6 | The term represents a substance by means of symbols. | F | Water |
| 7 | The term used for the substances formed as a result of a chemical reaction | G | Nitric Acid |
| 8 | A compound containing one atom of zinc and two atoms of chlorine. | H | Products |
| 9 | The chemical name for nitrogen monoxide. | I | Phosphorus |
| 10 | A polyatomic molecule. | J | Zinc Chloride |
Write the names of elements from the following symbol:
Ir
Complete the table by writing the symbols of the following elements
| Element | Symbol |
| Aluminum | Al |
| Nickel | |
| Bromine | |
| Helium | |
| Magnesium |
