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प्रश्न
Fill in the blank
A new substance is always formed in a _______ change.
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उत्तर
A new substance is always formed in a chemical change.
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संबंधित प्रश्न
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Formation of manure from leaves is a physical change.
Fill in the blank.
The formation of gas bubbles in a liquid during a reaction is called ......................
TRUE \ FALSE
Ammonia is a good oxidizing agent.
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.
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
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Oxygen is a ______ in respiration.
What is observed in performing the following :
| Hydrogen | Oxygen | Carbon dioxide | Chlorine | |
| Litmus test | ||||
| Apply a burning splint to the gas | ||||
| Colour of gas | colourless | colourless | colourless | greenish-yellow |
| Odour of gas |
State the original colour of the following substance and colour of residue obtained after heating.
Lead nitrate
Complete the table given below.
| Heat on ammonium dichromate | Name of neutral gas evolved |
Complete the table given below.
| Heat on Zinc nitrate | Colour of residue |
Give a balanced equation for the conversion of a soluble lead salt to an insoluble lead salt – formed as a white precipitate.
______ gas causes tears in our eyes while cutting onions.
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.
The percentage composition of Nitrogen in Ureas is ______.
______ occurs in the absence of air and in the presence of micro-organisms such as yeast.
Iron and rust are the same substances.
Magnesium + oxygen → magnesium oxide.
2Mg + O2 → 2Mg O
Write a note on the catalyst.
We are advised to not to play with fireworks. Give reason.
Write a note on the following:
Fermentation
What is thermochemical reactions?
