Tag: classification of changes

Questions Related to classification of changes

Which of the following is not considered a temperature scale? 

  1. Fahrenheit

  2. Kelvin

  3. Calorie

  4. Celsius


Correct Option: C
Explanation:

Calorie is used to measure the amount of energy needed to raise the temperature of one gram/kilogram  of a substance like water by one degree.

Iron pipes coated with zinc do not get rusted easily.

  1. True

  2. False


Correct Option: A
Explanation:

It is true.

Coating iron with zinc is known as galvanizing. Iron metals get rusted when in contact with oxygen and moisture (air).
If coated with zinc, no interaction between oxygen and iron is there and hence the pipe does not get rusted easily.

When an iron nail is added to acidic copper sulphate solution, the colour of the deposit on the iron nail is:

  1. brown

  2. blue

  3. green

  4. pink


Correct Option: A
Explanation:

When a nail is added to acidic copper sulphate solution, the color of the deposit on the iron nail is brown. Copper sulphate reacts with iron to form iron sulphate and copper. Brown colored copper deposits on nail.

A change in which a substance undergoes changes in its physical properties is called:

  1. chemical change

  2. physical change

  3. no change

  4. biological change


Correct Option: B
Explanation:

A change in which a substance changes its physical properties like appearance, texture, colour, odour, melting points, boiling points, density, solubility, polarity etc... are called physical changes. 


Physical properties can be observed or measured without changing the composition of matter. They are used to observe and describe matter.

Hence, the correct option is $\text{B}$

When substance cool off, there is a decrease in:

  1. size of substance

  2. vibrations of the molecules

  3. temperature

  4. all of the above


Correct Option: D
Explanation:

When a substance cools off, the size of substance, vibrations, a temperature of the substance decreases, as the heat is dissipated out resulting in the decrease in the size of the substance, and the internal vibrations between the molecules also decrease as the temperature decreases, due to the loss of heat.

A metal ball which is passing through metal ring will not pass after :

  1. heating

  2. freezing

  3. constant conditions

  4. refrigerating


Correct Option: A
Explanation:

All metals have a property of expansion when heated. Since the metal ball is heated, it will expand and will not pass the ring now.


Thus heating is the correct answer.

Hence the option A is correct.

Things or processes which cannot be reversed are called

  1. Irreversible process

  2. Reversible process

  3. Cyclic process

  4. None of the above


Correct Option: A
Explanation:

Things or processes which cannot be reversed are called irreversible process Burning of coal is irreversible as it will not produce coal again.

Which of the following processes prevents iron from rust?

  1. Galvanization

  2. Painting

  3. Both a and b

  4. None of the above


Correct Option: C
Explanation:

Galvanization(Coating of non-reactive metal on iron) and painting prevents iron to get in contact with moisture thus prevent it from rusting. 


Hence, option C is correct.

Permanent change is a :

  1. Physical change

  2. Chemical change

  3. Both physical and chemical change

  4. None of the above


Correct Option: B
Explanation:

A chemical change is permanent. A new substance is formed.


Forms of energy, such as heat, light or electricity, may be emitted or absorbed during a chemical reaction. A chemical change is generally irreversible.

Hence option B is correct.

Change of water into vapor (Vaporization) is which of the following change

  1. Physical and reversible change.

  2. Chemical and reversible change.

  3. Physical and irreversible change.

  4. Irreversible change


Correct Option: A
Explanation:

Vapor is another physical state of water. Water can be obtained from the  condensation of vapor. This is a physical and reversible change.