Download Thermochemistry is the study of the change in thermal energy

internal energy of a chemical system (the
chemicals we are focused on) has three
possible outcomes:
1. The temperature can increase
2. There could be a change of state
3. There could be a chemical reaction
Thermochemistry is the study of the change in
thermal energy (energy due to the motion of
particles). It takes place during physical and
chemical changes.
Energy is defined as the ability to do work.
Work is defined as a force exerted over a
distance. There are two types of energy, kinetic
and potential. Kinetic energy is the energy of
motion. Potential energy is stored energy.
There are many different forms of energy, such
as chemical, thermal, nuclear, electrical,
mechanical, sound, solar, magnetic, etc.
Two terms that students find confusing are heat
and temperature. Heat is the energy transferred
between two objects or systems that are at
different temperatures. Temperature is a
measure of the average kinetic energy of a
substances’s particles.
Temperature is measured with a thermometer,
while heat transfer is measured with a
calorimeter.
LESSON EXERCISES
Energy can be converted from one form to
another. For example, electrical to heat;
electrical to light; electrical to sound; chemical
to mechanical; chemical to electrical; chemical
to thermal.
1. Define thermal energy, kinetic energy, and
potential energy.
Chemical reactions require a minimum amount
of energy to take place. This energy is needed
to break certain chemical bonds of the
reactants. Sometimes the energy is thermal
energy from the motion of the particles of the
reactants, or from a Bunsen burner. Other
times, it is supplied as ultraviolet light energy
or as electrical energy from passing an
electrical current through the chemical system.
3. What types of energy can be produced as a
result of a chemical reaction?
Chemical reactions can also be used to produce
energy. Some examples would be thermal
(heat) energy, light energy, mechanical energy,
and electrical energy (dry cell batteries). The
energy involved in chemical reactions is from
breaking and making chemical bonds.
Internal energy is the sum of all of the energy
contained in a chemical system. The energy of
all of the atoms, molecules, or ions within a
system. It is made up of both kinetic and
potential energies. The kinetic energy is from
the translational, rotational, and vibrational
motions of the particles. The potential energy is
from the positions of the particles (attractive
and repulsive forces). An increase in the
2. What types of energy can be used to start a
chemical reaction?