Advertisements
Advertisements
प्रश्न
Which of the following are chemical changes?
(i) Decaying of wood
(ii) Burning of wood
(iii) Sawing of wood
(iv) Hammering of a nail into a piece of wood
विकल्प
(i) and (ii)
(ii) and (iii)
(iii) and (iv)
(i) and (iv)
Advertisements
उत्तर
(i) and (ii)
Explanation:
Decaying of wood and burning of wood are chemical changes since there is a change in the chemical composition of wood. Sawing of wood and hammering of a nail into a piece of wood are physical changes since there is no change in the composition of the wood during these changes.
APPEARS IN
संबंधित प्रश्न
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Iron pipes coated with zinc do not get rusted easily.
FILL IN THE BLANK
A .............. change is a temporary change.
Is kerosene an electrolyte or a non-electrolyte ?
What do you observe when :
an iron nail is kept in tap water for few days
What do you observe when dilute sulphuric acid is added to the following:
Sodium Sulphide
Represent the addition of dilute sulphuric acid to zinc by means of a chemical equation. State the function of the arrow between the reactants and products.
Give reason for the following:
Even though rusting is an exothermic reaction, the heat evolved when an iron nail rusts is unnoticeable.
Select the correct answer from the options given below:
State the gaseous product formed, when
An active metal reacts with dilute sulphuric acid.
Assertion: The formation of iron oxide from iron is a chemical change.
Reason: For the rust to form from iron, it must be exposed to air and water.
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Can you change rust back into iron by some simple method?
