Going to have a exam please help me :)

[no idea]

will the potential energy different between 99 oC water and 1 oC water ?

[Kurdt]

Yes the potential energy is different as the hotter water has more thermal energy which manifests itself as faster vibration.

[Moe]

That is kinetic energy, not potential energy.

[Kurdt]

Yes that is true in terms of individual water molecules, but the water is effectively storing it as potential energy if it is thermally isolated. When considering stored energy of gas or liquid or solid (stored as in potential) you always consider the gravitational, thermal (or translational) and any kind of rotational and vibrational energy. In the case of the gas the pressure and volume also have an effect.

[uranium_235]

The question is too ambiguous. It does not provide the amound of water under each condition.

[Kurdt]

Thats hardly a necessary requirement. If you used a bit of logic and concluded he was talking about the same amount then a simple quantitative description would suffice.