Physical vs Chemical Changes

Q.

The process of freezing is an example of a physical change even though water and ice have different properties, why?

Q.

Ammonium chloride is also sublimable solid . Give a reason why sublimation of ammonium chloride involves a physical & Chemical change.

Q. When water is frozen it forms ice that has different properties.Why then do we say that freezing is a physical change?

Q.

burning of a candle maybe considered as showing physical and chemical changes occuring simultaneously ?

Q.

Which of the following is not a desirable change?

1. Formation of curd

2. Formation of clouds

3. Rusting of iron

4. Ripening of fruits

Q.

Is burning a candle is a chemical or physical change or both

Q. What do you understand by Phase changes? Explain. [2 MARKS]

Q. Megha was told to observe an experiment and note down its details. This is what she wrote
A jar of clear water was put on the boil. The steam was allowed to escape. When the volume of water became almost half its original volume, the gas was switched off.
When the water cooled down to room temperature, a powdery substance whitish in colour was seen stuck to its sides.
Megha was told to
(1) To name the process from the mileu of names:- galvanization, precipitation , sublimation, corrosion, evaporation.
(2) To name the powdery substance.
(3) To explain why this powdery substance formed.
(4) What kind of change could this be? [2 MARKS]

Q. Identify the processes which are wrongly paired.

1. Sublimation - Physical change
2. Crystallisation - Chemical change
3. Condensation - Physical change
4. Corrosion - Physical change

Q. Consider the following statements.
Statement 1: Crushing a can is an example of chemical change.
Statement 2: Folding a paper is not a physical change.

1. Both the statements are true.
2. Both the statements are false.
3. Only statement 2 is true.
4. Only statement 1 is true.

Q. Consider the following statements.
Statement 1: Crushing a can is an example of chemical change.
Statement 2: Folding a paper is not a physical change.

1. Both the statements are false.
2. Both the statements are true.
3. Only statement 1 is true.
4. Only statement 2 is true.

Q. While burning a candle, the melting of wax is a change whereas the burning of wick is a change.

1. physical
2. chemical
3. periodic
4. natural

Q.

When we burn a candle, which of the following changes occur?

1. Physical Change

2. Chemical Change

3. Both physical and chemical change

4. Neither physical nor chemical change

Q. Choose the correct answer for the following analogy.
Physical change : Boiling : : Chemical change: _________

1. Melting
2. Burning
3. Condensation
4. Evaporation

Q. How many images involve a chemical change?

1. 2

Q. Match the correct pairs.

1. 
2. 
3. 
4. 
5. 
6. 

Q. The process of conversion of a substance to its gaseous state directly from its solid state is called _____.

1. condensation
2. sublimation
3. boiling
4. evaporation