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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
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Iron and rust are the same substances.
How do the following help in bringing about a chemical change?
light.
Complete and balance the following chemical equations:
Zn + `"H"_2"SO"_4` `→`
(dil)
What are oxides ?
What do you observe when :
an iron nail is kept in tap water for few days
Fill in the blank.
Melting of ice is a _______ change.
Fill in the blank:
In some chemical reactions an insoluble ________ is formed when two solutions are mixed.
Out of sodium and sulphur which is a metal? Explain its reaction with the oxygen.
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
The conversion of ferrous sulphate to ferric sulphate is ______ reaction.
State the conditions necessary for a chemical change or reaction.
Give an example of a reaction where the following are involved
Light
Give an example of the following chemical change.
A reaction where colour change is noticed
Write the chemical reaction where the following changes are observed.
Gas is evolved
Complete and balance the following reaction:
\[\ce{Pb(NO3)2 ->[\Delta]}\]
Name the gases which Turn moist red litmus blue.
Name: Two carbonates do not produce carbon dioxide on heating.
Give a chemical test to distinguish between the following gases.
NH3 and SO2
Write your observation and a balanced equation in the case of the following substances being heated.
Copper nitrate.
Give balanced equation for the following conversion affected by heat alone on the substance:
Copper carbonate to copper oxide
Complete the table given below.
| Heat on Zinc nitrate | Colour of residue |
State the following reaction represent oxidation or reduction.
\[\ce{Al->Al+++}\]
Complete the statement by filling in the blank with the correct word:
The reddish-brown precipitate obtained during a double decomposition precipitation reaction between an iron salt and alkali is __________.
NPK are the primary nutrients for plants.
On heating calcium carbonate gets converted into calcium oxide and carbon dioxide.
(a) Is this a physical or a chemical change?
(b) Can you prepare one acidic and one basic solution by using the products formed in the above process? If so, write the chemical equation involved.
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 word equations for two chemical reactions with the help of materials given in the box.
Air, copper sulphate, iron, vinegar, iron oxide, carbon dioxide, iron sulphate, copper, lime water, water
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.
Iron and rust are the same substances.
______ is a chemical substance is used in whitewashing.
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.
