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What is a chemical reaction?
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A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Addition of dilute acid to an active metal.
Concept: undefined >> undefined
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A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Addition of dilute hydrochloric acid to silver nitrate.
Concept: undefined >> undefined
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Addition of water to quicklime.
Concept: undefined >> undefined
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Thermal decomposition of mercury [II] oxide.
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Match the chemical reactions in List I with the appropriate answer in List II.
| List I | List II | ||
| 1. | \[\ce{XY⇌[heat]X + Y}\] | A: | Displacement reaction |
| 2. | \[\ce{XY->X + Y}\] | B: | Double decomposition |
| 3. | \[\ce{X+Y- + A+B^-->X+B- + A+Y-}\] | C: | Endothermic reaction |
| 4. | \[\ce{X + YZ->XZ + Y}\] | D: | Thermal dissociation |
| 5. | \[\ce{X + Y->[heat]XY -\Delta}\] | E: | Decomposition reaction |
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What are the uses of coal?
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Define interconversion of states of matter. What are the two factors responsible for the change of states of matter?
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What happens to water if it is heated and Explain the phenomenon of change of state of water.
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State the law of conversation of mass.
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What do you observe when, barium chloride solution is mixed with sodium sulphate solution ?
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Give reasons:
A gas can fill the whole vessel in which it is enclosed.
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Give reasons:
Solids cannot be compressed.
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When magnesium is burnt in air, there is an increase in mass after the reaction.
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Fill in the blank:
The change of a solid into a liquid is called melting or................
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Fill in the blank:
The process in which a solid directly changes into a gas is called ....................
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Fill in the blank:
The change of water vapour into water is called ......................
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Fill in the blank:
The temperature at which a liquid starts changing into its vapour state is ______.
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Give two example of the following:
The substances which sublime.
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