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प्रश्न
Fill in the blank
A change in which the substance can be brought back to its original state is called a _______ change.
उत्तर
A change in which the substance can be brought back to its original state is called a reversible change.
APPEARS IN
संबंधित प्रश्न
How do the following help in bringing about a chemical change?
pressure.
What do you observe when Iron nail is kept in copper sulphate solution for sometime.
TRUE \ FALSE
Copper can displace iron from iron sulphate.
TRUE \ FALSE
Evaporation of water is a physical change. True or false ?
TRUE \ FALSE
The evolution of a gas during a chemical reaction is shown by an arrow pointing downwards. True or false ?
TRUE \ FALSE
Temperature at which a liquid starts boiling is known as the boiling point of that liquid. True or false ?
What are chemical reactions?
How is a strong electrolyte different from a weak electrolyte?
A solution of a substance ‘X’ is used for white washing Name the substance ‘X’ and write its formula.
Explain by writing a word equation.
Bubbles are seen on adding lemon juice to baking soda.
Define Photochemical reaction
Give an example
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
What do you understand by 'chemical reaction'?
Complete and balance the following reaction:
\[\ce{CuCO3 ->[\Delta]}\]
Complete the following table and write your observations.
|
Hydrogen sulphide |
Ammonia |
Sulphur dioxide |
Hydrogen chloride |
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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 |
Distinguish by heating the following in dry test tubs.
Zinc nitrate and copper nitrate.
Write your observation and a balanced equation in the case of the following substances being heated.
Zinc carbonate.
Select the correct answer for the following options:
The black residue obtained on heating copper carbonate.
Give balanced equation for the following conversion affected by heat alone on the substance:
Hydrated copper sulphate to sulphur dioxide
Explain the Silver nitrate solution is kept in coloured reagent bottles in the laboratory.
Give a balanced equation for the conversion of a soluble lead salt to an insoluble lead salt – formed as a white precipitate.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Lead nitrate.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
______ gas causes tears in our eyes while cutting onions.
Write some materials prepared by chemical changes.
Which of the following is/are true when milk changes into curd?
- Its state is changed from liquid to semi-solid.
- It changes colour.
- It changes the taste.
- The change cannot be reversed.
Choose the correct option from below:
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 the formation of rust from iron is a chemical change?
Is the conversion of milk into ice cream a chemical change?
Which is used as a catalyst during the process of hydrogenation of oils?
