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प्रश्न
Write true or false :
No new substance is formed during a chemical reaction.
पर्याय
True
False
उत्तर
False
APPEARS IN
संबंधित प्रश्न
When carbon dioxide is passed through lime water, it turns milky due to the formation of ______.
The chemical name of baking soda is ______.
Changes in which new substances are formed are called ______ changes.
How would you show that setting of curd is a chemical change?
What are (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them.
Write a short note on the information derived from a balanced chemical equation.
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.
Explain the following reaction with one suitable example of Combination reactions .
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Water
Give an example of a reaction where the following are involved
Catalyst
Give reason for the following:
Colourless concentrated sulphuric acid in a test tube changes to blue on adding a small piece of copper to it.
State the type of reactions for the following represent and balance the ones that are not balanced.
NaOH + HCl → NaCl + H2O
State the original colour of the following substance and colour of residue obtained after heating.
Lead nitrate
What do you observe when Cl2 is passed through potassium iodide (KI) solution.
Name the following:
The type of change physical or chemical involved – ‘during respiration in human beings’.
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc carbonate to zinc oxide
Match the chemical reactions in List I with the appropriate answer in List II.
| List I | List II | ||
| 1. | \[\ce{XY⇌[heat]X + Y}\] | A: | Displacement reaction |
| 2. | \[\ce{XY->X + Y}\] | B: | Double decomposition |
| 3. | \[\ce{X+Y- + A+B^-->X+B- + A+Y-}\] | C: | Endothermic reaction |
| 4. | \[\ce{X + YZ->XZ + Y}\] | D: | Thermal dissociation |
| 5. | \[\ce{X + Y->[heat]XY -\Delta}\] | E: | Decomposition reaction |
State the following reaction represent oxidation or reduction.
\[\ce{H->H+}\]
Give a suitable example with an equation to show the representation of a chemical reaction.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Copper nitrate.
The chemical change is ______.
______ is not a chemical change.
When an aqueous solution of potassium chloride is added to an aqueous solution of silver nitrate, a white precipitate is formed. Give the chemical equation of this reaction.
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
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.
Which of the following statement is incorrect for a chemical reaction?
Write five changes in the characteristics of a substance that can take place during a chemical change.
Write the effects of chemical reactions.
