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Question
Oxygen is very essential for us to live. It forms 21% of air by volume. Is it an element or compound?
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Solution
Oxygen is an element. It contains the atoms of oxygen of the same kind.
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RELATED QUESTIONS
Define: Atom
Give one use of the following substance:
Iron
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 |
Select the correct answer from the choice given below.
The negatively charged particles in an atom
Give an example of two liquids that form heterogeneous mixtures.
Match the separation of components in List I with the most appropriate process in List II.
| List I | List II |
| 1. Naphthalene from naphthalene & sodium chloride. | A: Separating funnel |
| 2. Cream from milk. | B: Sublimation |
| 3. Kerosene oil from kerosene oil & water. | C: Boiling |
| 4. Lead nitrate from an aqueous solution of lead nitrate. | D: Centrifugation |
| 5. Ammonia from an aqueous solution of ammonia. | E: Distillation |
Elements : Combine to form compounds :: Compounds : ______.
Classify the following as elements and compounds.
Water, Common salt, Sugar, Carbon dioxide, Iodine and Lithium
Higher Order Thinking Skills.
List out the metals, non-metals and metalloids which you use in your house, schools. Compare their properties.
Match the following:
| 1. | Co2 | a. | Robert Boyle |
| 2. | Sulfur | b. | Making mobile phones |
| 3. | Element | c. | triatomic molecule |
| 4. | Gallium | d. | Polyatomic molecule |
