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प्रश्न
Fill in the blank:
During a chemical reaction transfer of ________ takes place.
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उत्तर
During a chemical reaction transfer of energy takes place.
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संबंधित प्रश्न
How do the following help in bringing about a chemical change?
pressure.
Complete and balance the following chemical equations:
Zn + `"H"_2"SO"_4` `→`
(dil)
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{NH3_{(g)} + HCl_{(g)} -> NH4Cl_{(s)}}\]
Fill in the blank
A new substance is always formed in a _______ change.
Differentiate between in Chemical reaction and chemical equation.
Write true or false :
No new substance is formed during a chemical reaction.
When electric current is passed through acidulated water ______ of water takes place.
Write the chemical reaction where the following changes are observed.
Colour change is noticed
Give reason for the following:
Silver nitrate solution is kept in coloured bottles.
Multiple choice:
Thermal decomposition of sodium carbonate will produce
What do you understand by 'chemical reaction'?
Name: A brown gas
What is observed in performing the following :
| Hydrogen | Oxygen | Carbon dioxide | Chlorine | |
| Litmus test | ||||
| Apply a burning splint to the gas | ||||
| Colour of gas | colourless | colourless | colourless | greenish-yellow |
| Odour of gas |
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.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Copper nitrate.
Analogy:
H2O: Water:: NaCl: ______.
Give two examples for the following case:
Chemical changes
Give an example of a chemical reaction for the following situation:
A change in colour is observed
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Do you think formation of rust from iron is a chemical change?
Why is spoiling food a chemical change?
