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प्रश्न
Name the following:
The type of change physical or chemical involved – ‘during respiration in human beings’.
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उत्तर
Chemical Change.
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संबंधित प्रश्न
Give reason .
A person suffering from acidity is advised to take an antacid.
TRUE \ FALSE
A precipitation reaction takes place only in a solution.
TRUE \ FALSE
The evolution of a gas during a chemical reaction is shown by an arrow pointing downwards. True or false ?
Fill in the blank:
During a chemical reaction transfer of ________ takes place.
Write true or false :
When potassium iodide solution is added to lead acetate solution a red precipitate is formed.
Name the type of chemical reaction shown by the following equation:
NaOH + HCl → NaCl + H2O
State the conditions necessary for a chemical change or reaction.
Define an electrochemical reaction.
Complete and balance the following reaction:
\[\ce{NH3 + O2 ->[\Delta]}\]
Name: A greenish-yellow gas.
Write your observation and a balanced equation in the case of the following substances being heated.
Copper nitrate.
Distinguish by dilute sulphuric acid.
Sodium Sulphite and sodium carbonate?
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.
Complete the table given below.
| Addition of dil. H2SO4 to FeS | Odour of gas evolved |
A reaction between an acid and a base is called ______.
Chemists identify gypsum as a natural indicator.
______ is a natural indicator.
______ occurs in the absence of air and in the presence of micro-organisms such as yeast.
Assertion (A): Cutting paper into very small pieces is an irreversible change.
Reason (R): Physical changes are always reversible.
Collect information about the types of fuels used for cooking in your area. Discuss with your teachers/parents/others which fuels are less polluting and why.
