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प्रश्न
Fill in the blank
A new substance is always formed in a _______ change.
उत्तर
A new substance is always formed in a chemical change.
APPEARS IN
संबंधित प्रश्न
Define; catalyst.
Complete and balance the following chemical equations:
Ba`"CI"_2` + `"H"_2"SO"_4` `→`
(aq.) (aq.)
Give reason.
Acidic soil is treated with quick lime.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Which one of the following alters the rate of the chemical reaction without itself undergoing any change?
- temperature and Pressure
- concentration of reactants
- presence of catalyst
- none of these
Fill in the blank
A change in which the substance can be brought back to its original state is called a _______ change.
Write true or false :
Hydrogen sulphide has rotten egg smell .
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
What is the reaction called when oxidation and reduction take place simultaneously? Explain with one example.
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
The white particles of baking soda disappear when put in lemon juice. This means that it is a ______ change.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Sodium chloride
Give an example of a reaction where the following are involved
Heat
Give an example of the following chemical change.
Two solids combine to form a liquid
Give an example of the following chemical change.
A reaction where colour change is noticed
Give reason for the following:
Molybdenum is used in the manufacture of ammonia.
What is a chemical change? Give two examples of chemical change?
Define:
Photochemical reaction
Give one example
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 |
What do you observe when Cl2 is passed through potassium iodide (KI) solution.
Distinguish by heating the following in dry test tubs.
Zinc nitrate and copper nitrate.
What is a chemical reaction?
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.
State the following reaction represent oxidation or reduction.
\[\ce{Fe++->Fe+++}\]
Differentiate between the following:
Neutralization reaction and a precipitation reaction.
Higher order Thinking question
Peeled and unpeeled banana does not look the same. Does that mean peeling banana is a chemical change?
Photosynthesis is a chemical reaction that takes place in the presence of ______.
Mention the various conditions required for a chemical reaction to occur.
Classify each of the following, as a physical or a chemical change. Give reasons.
(a) Drying of a shirt in the sun.
(b) Rising of hot air over a radiator.
(c) Burning of kerosene in a lantern.
(d) Change the colour of black tea by adding lemon juice to it.
(e) Churning of milk cream to get butter.
Which of the following statement is incorrect for a chemical reaction?
Classify the following processes into physical or chemical changes:
(i) Beating of aluminium metal to make aluminium foil.
(ii) Digestion of food.
(iii) Cutting of a log of wood into pieces.
(iv) Burning of crackers.
Write a note on the following:
Curdling of milk
