Chapter 4 Properties of Matter

4.5 Energy
energy is the capacity of matter to do work
exists in many form: mechanical, chemical,
electrical, heat, nuclear, radiant or light energy
matter can have both potential and kinetic energy
potential energy (PE) – stored energy
kinetic energy (KE) – energy that matter
possesses due to its motion
energy can be converted from one form to another
mechanical energy
electric generator
> 90% efficiency
electrical energy
solar energy
~ 15% efficiency
electrical energy
in chemistry, energy is most frequently expressed
as heat
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