Specific Heat Capacity

Some substance have a heat content which is naturally higher than others. 

For example you can walk on grass on a hot day but you probably will not be able to walk on a sandy beach with the same amount of comfort on the same day. 

Sand has a higher specific heat capacity than grass.

The heat content (Q) of an object can be calculated in terms of :

  • its mass (m)
  • its temperature change (D)
  • and its specific heat capacity (c)

We ca summarize the above in the following  mathematical expression:

Q = m x c x DT

The specific heat capacity of a substance is defined as the amount of heat energy that must be added or removed from a substance to change the temperature of 1 kg of the substance by 1 K (Kelvin degree).


Exercise #2

A. A 700 g  aluminum kettle (caluminum = 920 J/Kg/k)  is left to cool off for 10 minutes after boiling water.  Its final temperature reaches 350C. 
Assuming that its initial temperature was that of boiling water (100 0C), how much heat energy did the kettle lose in 10 min?

B. If it took 4 minutes for the kettle to boil 500 mL of water (cwater = 4200 J/Kg/k) from 200C to 1000C  what is the power of the kettle?
[Density of water = 1g/mL]