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प्रश्न
Oxygen is very essential for us to live. It forms 21% of air by volume. Is it an element or compound?
उत्तर
Oxygen is an element. It contains the atoms of oxygen of the same kind.
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संबंधित प्रश्न
Name the technique that you use if only the solid component of a solution is required.
Name: Two substances used to make jewellery.
Give reason: A frying pan is made up of steel but its handle is made up of wood.
Give reason: Graphite is used to make a lead of the pencils.
Match the compounds in List I – 1 to 20 with their correct formulas from in List II-A to T.
| List I | List II | ||
| 1 | Hydrochloric acid | A | NaCI |
| 2 | Potassium Hydroxide | B | NaOH |
| 3 | Sulphuric Acid | C | KCI |
| 4 | Zinc Hydroxide | D | Ca(OH)2 |
| 5 | Sodium Chloride | E | CaS |
| 6 | Nitric Acid | F | CuSO4 |
| 7 | Calcium Hydroxide | G | CaCO3 |
| 8 | Carbonic Acid | H | NH4CI |
| 9 | Sodium hydroxide | I | HCI |
| 10 | Copper sulphate | J | ZnO |
| 11 | Potassium Chloride | K | HNO3 |
| 12 | Calcium Carbonate | L | H2CO3 |
| 13 | Magnesium Sulphide | M | MgS |
| 14 | Zinc Sulphate | N | MgO |
| 15 | aluminium Hydroxide | O | KOH |
| 16 | Sodium Carbonate | P | ZnSO4 |
| 17 | Calcium Sulphide | Q | Na2CO3 |
| 18 | Magnesium Oxide | R | H2SO4 |
| 19 | Zinc Oxide | S | AI(OH)3 |
| 20 | Ammonium Chloride | T | Zn(OH)2 |
Give three differences between elements & compounds with relevant examples.
Select the correct answer from the choice given below to complete the sentence :
Compounds are ____________ in nature.
Select the correct answer from the choice given below to complete the sentence :
An example of a monoatomic molecule is ___________.
The first letter of an element is always written in ______ letter.
Higher Order Thinking Skills.
List out the metals, non-metals and metalloids which you use in your house, schools. Compare their properties.
