Properties for Heat Capacity and Specific Heat Capacity

[Dahlia Kirov 3A]

Hey!

In a step-up session it was mentioned that specific heat is an intensive property independent of the amount of material, but heat capacity is an extensive property as it takes into account the amount of substance. Would someone mind explaining how / why specific heat capacity is an intensive property if heat capacity is an extensive property?

[Jocelyn Ni 3C]

Hi!
Extensive property depends on the amount of substance present. Heat capacity is an extensive property as it only tells us the heat required to raise the temperature of an object by 1°C --- it doesn't tell us anything about the amount of the substance. Heat capacity is proportional to the amount of substance present and will change with that which makes it extensive. On the other hand, the specific heat capacity is the heat capacity per gram. It is always the same no matter how much substance is present. It specifies the amount (per gram). So specific heat capacity is an intensive property.

[Sarah Wang 2G]

Hello!

As previously stated, the specific heat of a substance is a constant regardless of how much of the substance (intensive) you have because it is the heat capacity of 1 gram of the substance. Similarly, the molar heat capacity is the heat capacity of 1 mole of the substance, which also makes it an intensive property. However, the heat capacity is extensive because it is the amount of energy required to heat the amount of substance you have by 1 degree Celsius and increases as the amount of substance increases. If it helps, you can think of a lake as an example. It would take a lot more heat to boil the lake than it would to boil a small pot of water. Since both are composed of water, they would have the same specific and molar heat capacity. However, the lake has a much greater volume and would need to absorb a lot more energy before boiling; therefore, it would have a greater heat capacity than the pot of water.