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प्रश्न
How do the following help in bringing about a chemical change?
light.
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उत्तर
Some chemical reactions can take place in the presence of light. Ex. Photosynthesis.
\[\ce{6CO2 + 6H2O⇌[sunlight][Chlorophyll]\underset{\text{glucose}}{C6H12O6 +6O2}}\]
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संबंधित प्रश्न
How would you show that setting of curd is a chemical change?
How do the following help in bringing about a chemical change?
pressure.
How do the following help in bringing about a chemical change?
heat.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Reduction is a chemical reaction in which there is
- removal of hydrogen
- removal of oxygen
- addition of oxygen
- none of these
FILL IN THE BLANK
In a double decomposition precipitation reaction both the reactants must be ............ soluble.
FILL IN THE BLANK
The new substances formed during a chemical reaction are called the ..................
Write true or false :
No new substance is formed during a chemical reaction.
Explain the following reaction with one suitable example of Displacement reaction.
| Reactants | Products | Type of chemical reaction |
| BaCl2(aq) + ZnSO4(aq) | H2CO3(aq) | Displacement |
| 2AgCl(s) | FeSO4(aq) + Cu(s) | Combination |
| CuSO4(aq) + Fe(s) | BaSO4↓ + ZnCl2(aq) | Decomposition |
| H2O(l) + CO2(g) | 2Ag(s) + Cl2(g) | Double displacement |
Give a chemical test to distinguish between the following gases.
HCl and H2S
Name the following:
The type of change physical or chemical involved – ‘during respiration in human beings’.
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.
| Flame test for calcium chloride | Acid used for flame test |
Can a nickel spatula be used to stir copper sulphate solution? Justify your answer.
______ is a natural indicator.
Two chemical species X and Y combine together to form a product P which contains both X and Y
\[\ce{X + Y -> P}\]
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following concerning the species X, Y and P are correct?
(i) P is a compound
(ii) X and Y are compounds
(iii) X and Y are elements
(iv) P has a fixed composition
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.
Are these changes chemical in nature?
Rusting of iron is ______.
When magnesium is burnt in the air, a new substance is formed which is ______.
How would you show that the settling of curd is a chemical change?
