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प्रश्न
Fill in the blank.
Melting of ice is a _______ change.
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उत्तर
Melting of ice is a physical change.
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संबंधित प्रश्न
Complete and balance the following chemical equations:
Zn + `"H"_2"SO"_4` `→`
(dil)
Complete and balance the following chemical equations:
Ba`"CI"_2` + `"H"_2"SO"_4` `→`
(aq.) (aq.)
TRUE \ FALSE
Electrolytic refining is a method in which a thin coating of a metal is done over another metal.
Fill in the blank
A new substance is always formed in a _______ change.
Fill in the blank
A change in which the substance can be brought back to its original state is called a _______ change.
State four conditions necessary for chemical reactions to take place.
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
Explain the following reaction with one suitable example of Displacement reaction.
A solution of a substance ‘X’ is used for white washing write the reaction of the substance ‘X’ named in (a) above with water.
State the original colour of the following substance and colour of residue obtained after heating.
Lead nitrate
Give a chemical test to distinguish between the following gases.
H2 and CO2
Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium dichromate.
Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.
________ is a chemical substance which alters the speed of a chemical reaction.
Silver articles turning black: ______:: Boiling of H2O: physical change ______.
A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.
Write a word equation for the chemical change, if any.
Magnesium + oxygen → magnesium oxide.
2Mg + O2 → 2Mg O
Match the following:
| Column I | Column II | ||
| 1. | Burning of coal | a. | Rusting |
| 2. | Painting of a surface | b. | Evaporation |
| 3. | Dipping iron in the water | c. | Chemical change |
| 4. | Salt from seawater | d. | Prevention of rusting |
Both CO2 and H2 gases are ______.
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.
