help with kinetic energy

Question

if the average kinetic energy of a substance changes,

 

a.  its temperture changes

b.  it may change phase

c.  thermal energy has been transferred  into or out of the substance

d.  all of these

 

thanks

Answer 1

The answer is d, all of these.

 

Temperature is a measure of the average kinetic energy of the particles of a substance: the higher the average kinetic energy, the greater the temperature.  Hence the temperature will go up or down as you increase or decrease the average kinetic energy.

 

If you add or remove enough kinetic energy, the substance may change phase.  Adding heat (energy) to ice will cause it to melt once it reaches the right temperature.  Adding more heat may cause it to boil into steam.

 

Thermal energy (heat) alters the average kinetic energy.  Adding heat raises the energy and thus the temperature.  Removing heat lowers the kinetic energy, and thus the temperature.