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प्रश्न
Write true or false :
When iron and sulphur are heated together a grey mass is formed which is attracted by a magnet .
पर्याय
True
False
उत्तर
False
APPEARS IN
संबंधित प्रश्न
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Condensation of steam is not a chemical change.
Define electrolysis.
How is a strong electrolyte different from a weak electrolyte?
Define chemical reaction.
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The substances which undergo chemical change are called _______
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
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State the conditions necessary for a chemical change or reaction.
Give an example of a reaction where the following are involved
Catalyst
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A reaction where colour change is noticed
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\[\ce{NH3 + O2 ->[\Delta]}\]
Name: Two carbonates do not produce carbon dioxide on heating.
Complete the following table and write your observations.
|
Hydrogen sulphide |
Ammonia |
Sulphur dioxide |
Hydrogen chloride |
|
|
Shake the gas with red litmus solution |
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|
Shake the gas with blue litmus solution |
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|
Apply a burning splint to a gas |
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Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium chloride
Represent the addition of dilute sulphuric acid to zinc by means of a chemical equation. State the function of the arrow between the reactants and products.
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\[\ce{Cu++->Cu}\]
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\[\ce{H->H+}\]
What kind of a change is associated with decaying of a plants?
Higher order Thinking question
A very hot glass on putting in cold water cracks. What does this change indicate?
Match the following:
| 1. | Sodium Chloride | a. | CaSO41/2H2O |
| 2. | Calcium sulphate dihydrate | b. | C2H5Oh |
| 3. | Magnesium sulphate hydrate | c. | CaSO4.2H2O |
| 4. | Calcium sulphate hemihydrate | d. | NaCl |
| 5. | Phenol | e. | MgSO4.H2O |
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\[\ce{X + Y -> P}\]
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(i) P is a compound
(ii) X and Y are compounds
(iii) X and Y are elements
(iv) P has a fixed composition
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When a candle burns, both physical and chemical changes take place.
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If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Can you change rust back into iron by some simple method?
Iron and rust are the same substances.
Magnesium + oxygen → magnesium oxide.
2Mg + O2 → 2Mg O
What is thermochemical reactions?
