Advertisements
Advertisements
प्रश्न
Chemical changes are accompanied by changes in energy.
Advertisements
उत्तर
In a chemical change, molecules and atoms rearrange themselves to form new substances. This rearrangement involves some energy changes. It can either be absorption or evolution of energy.
APPEARS IN
संबंधित प्रश्न
State whether the following is physical or chemical changes.
passing electric current through a heater rod —
Tick (√) the correct alternative from the choice given for the following statement
Burning is a
True or false?
During a physical change energy is either given out or absorbed by the system.
Melting of solid (wax) is a physical change.
Distinguish between the following.
Periodic change and non-periodic change
Under which different types can the following changes be classified?
Stretching of a spring.
Give reason.
A dry handkerchief gets wet at once on dipping in water, but it takes longer for a wet handkerchief to dry.
Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not.
| S. No. | Change | Can be reversed (Yes/No) |
| 1. | The sawing of a piece of wood | |
| 2. | The melting of ice candy | |
| 3. | Dissolving sugar in water | |
| 4. | The cooking of food | |
| 5. | The ripening of a mango | |
| 6. | Souring of milk |
What is the change?
Cut vegetables turn brown when exposed to air, this is due to ______.
