Question

Hello! I want to ask why do different substances' heat capacities differ? Btw this is a 2 point question so I guess there are two main points to mention. Thanks!

Answer 1

Specific heat capacity or SHC is defined (In chemistry at least) as: The amount of energy required to raise one gram of a substance by one kelvin.

Due to the weights of different molecules lighter substances contain more particles for a given weight and because all the particles are heated evenly (due to the property that a closed systems will seek to obtain a thermal equilibrium) lighter substances will have a higher SHC because there are more particles per gram

e.g.

The SHC of Hydrogen, which has an atomic weight of 1.008 AMU's is ~14.3

The SHC of Oxygen, which has an atomic weight of 16 AMU's is ~0.918

As you can see because hydrogen is ~16 times smaller than Oxygen, the increased number of particles per gram means that a lot more energy is required to raise them all by one kelvin

Answer 2

let the definition of specific heat capacity be: the amount of energy required to raise the temperature of one _mole_ of a substance by one Kelvin.

Answer 3

@Jire this is the definition of molar heat capacity not specific heat capacity. when you replaces one mole with one kg then that becomes the definition of specific heat.

Answer 4

1. it is material dependent.

Answer 5

Thanks guys!

Answer 6

well substance are made of molecules that are all bouncing around with heat energy. When the molecules are different sizes/arrangements they can move in different patterns,