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प्रश्न
State the original colour of the following substance and colour of residue obtained after heating.
Copper carbonate
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उत्तर
The colour of copper carbonate is green. On heating Copper carbonate, a black residue is formed and a gas is released which turns lime water milky.
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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.
Condensation of steam is not a chemical change.
Explain by writing a word equation.
Respiration is a chemical change.
Match the pairs.
| a. | Photosynthesis | i. | Tendency to lose electrons |
| b. | Water | ii. | Reactant in combustion process |
| c. | Sodium chloride | iii. | Chemical change |
| d. | Dissolution of salt in water | iv. | Covalent bond |
| e. | Carbon | v. | Ionic bond |
| f. | Fluorine | vi. | Physical change |
| g. | Magnesium | vii. | Tendency to form anion |
Explain the term reactant and product giving examples.
On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.
A coloured substance which leaves a black residue and evolves two gases one of which is acidic and coloured and the other neutral and colourless.
Complete the table given below.
| Heat on iodine crystals | Colour of vapours evolved |
Circle the odd one out. Give reason for your choice
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?
Iron and rust are the same substances.
Write a note on the following:
Curdling of milk
