Question

Which of the following is an intensive property?
[A] Enthalpy
[B] Entropy
[C] Specific heat
[D] Volume

Answer 1

HINT: Intensive properties are the properties which do not change on changing the amount of material in it. Here the correct answer is the property which gives us the amount of heat required to bring a certain temperature change in a substance.

COMPLETE STEP BY STEP SOLUTION:
We know that we can categorize physical properties of substances as intensive or extensive.
We can categorise them on the basis of how it changes when we change the size or extent of the system.
We can write the IUPAC definitions of extensive and intensive properties as- ‘An intensive property is one whose magnitude is independent of size of the system whereas an extensive quantity is one whose magnitude is additive for subsystems.
However, we can simply understand if a property is intensive or extensive by checking if it depends on the size, mass of the system.
-A property is intensive if it does not depend on the size of the system or amount of material in the system. Some common intensive properties are temperature, density, hardness of a substance etc.
- A property is extensive if it depends on the size of the system as well as amount of the material in the system. The most common example of extensive property that we often see is mass, volume or even entropy of the system.
Now, let us discuss the properties given to us in the options and find out if they are extensive or intensive.
Firstly, we have enthalpy. Enthalpy is an extensive property because we know that if we double the mass of a gas, its enthalpy is also doubled. Therefore, it is not the correct answer.
Next, we have entropy. Entropy is the randomness of a system. If we increase the mass of a system, entropy increases. Therefore, this is not the correct answer.
Then we have specific heat which is an intensive property. We know that specific heat is the ability of a substance to absorb heat energy at a particular temperature. It does not depend on the mass of the substance. Therefore, it is an intensive property.
And lastly we have volume which depends upon the mass thus is an extensive property.
We can see from the above discussion specific heat is an intensive property.

Therefore, the correct answer is option [C] Specific heat.

NOTE: There are certain properties which are neither intensive nor extensive. The most common example of such property is resistance. However, for some cases we consider resistance to be an extensive property but in general it is neither of them. Resistance is a geometric property. For example if we double the length of the wire, resistance is also doubled.