Cracking the SAT Chemistry Subject Test

ENERGY

You will have to know a few things about energy for the SAT Chemistry Subject
Test. First, remember that energy exists in different forms, but is always defined
as the ability to do work or transfer heat. Energy can exist as heat, light, kinetic
energy, or chemical bond energy. When we say kinetic energy, we’re talking
about the energy that an object possesses by virtue of the fact that it is moving. A
moving bus, train, or car has kinetic energy. When we deal with chemistry, we’re
usually thinking about molecules that move; moving molecules have kinetic
energy. The faster molecules move, the higher their kinetic energy.

What units are used to describe energy?

calories    (cal)

joules  (J) or  kilojoules  (1  kJ  equals  1,000   J)

One calorie (1 cal) is equal to slightly more than 4 J (4.186 J to be specific).

What instrument is used to measure energy?

a   calorimeter

Keep    the following   things  in  mind    when    considering energy:

Kinetic energy  is  the energy  contained   in  the movement    of  molecules.  The

greater  the     kinetic     energy,     the     faster  the     movement    and     the     higher  the

temperature of  the molecules.

Chemical    bonds   contain energy. Breaking    bonds   requires    energy; forming

bonds   releases    energy.

Heat    is  the transfer    of  kinetic energy  from    one thing   to  another.

A   calorimeter measures    energy.