Advertisements
Advertisements
Question
Give the reason why the following is considered as chemical changes.
Copper carbonate on heat gives copper oxide and carbon dioxide.
Solution
Copper carbonate [CuCO3] green colour on heating gives copper oxide [Black colour CuO] and CO2.
Hence composition is changed new substances CuO [Black] and CO2 with new properties are produced and it is irreversible reaction hence it is a chemical change.
\[\ce{\underset{\text{Green}}{CuCO3} ->[\Delta] \underset{\text{Black}}{CuO} + CO2}\]
APPEARS IN
RELATED QUESTIONS
Explain the following giving an example.
Pure substance
Tick the most appropriate answer
2. Melting of ice is a
- reversible change
- irreversible change
- chemical change
- none of these
Tick (√) the correct alternative from the choice given for the following statement
Which one of the following is volatile in nature ?
True or false
In a physical change no net energy change is involved.
Fill in the blank
Heat is ________ by a gas during the process of condensation.
Differentiate between a physical change and a chemical change with reference to – Energy change taking place during the respective change.
Match the examples of changes in List I with the correct type of change in List II.
| List I | List II |
| 1. Burning of paper | A: Physical change |
| 2. The ringing of an electric bell | B: Chemical change |
| 3. Curdling of milk | |
| 4. Electric light is switched on | |
| 5. Melting of butter |
Name the following.
A form of energy required for a chemical change.
When a woolen yarn is knitted to get a sweater, the change can be classified as ____________.
Classify the following changes as physical and chemical changes
A rough piece of wood is sanded and polished resulting in change in texture, Rusting of a iron nail, Painting the grill, Bending a paper clip, Pounding silver into thin plate, Rolling the chappathi dough into thin wire, Occurrence of day and night, eruption of volcano, burning of matchstick, dosa from the batter, blinking of eyelids, occurrence of a thunderstorm, rotation of the earth, formation of eclipses.
| Sr. No. | Physical changes | Chemical changes |
| 1. | ||
| 2. |
