� Energy- the ability to do work or produce heat
� Energy exists in two basic forms- potential energy and kinetic energy
� Potential energy is due to the composition or position of an object
Ex: the position of water stored behind a dam above the turbines of a hydroelectric
generating plant.
� Kinetic energy is energy of motion.
Ex: The potential energy from the dam is converted to kinetic energy when the dam gates
are opened.
� Kinetic energy is based on the constant random motion of atoms or molecules and is
proportional to the temperature.
� Potential energy depends on composition. (the type of atoms, the number and type of
chemical bonds, the particular way atoms are arranged)
Law of Conservation of Energy-
� In reactions, energy changes from one form to another, but the amount of energy does not
change.
� Law of Conservation of Energy- in any chemical reaction or physical process, energy can be
converted from one form to another, but it is neither created nor destroyed.
Chemical Potential Energy-
� Chemical potential energy- the energy stored in a substance because of its composition
Ex: C8H18 represents the principle components of gasoline.
-The chemical potential energy results from the specific arrangement of the carbon and
hydrogen atoms and the strength of the bonds that join them
-When the gasoline is burned, some of the stored energy is converted to work to propel
the wheels and other parts.
-Much of the potential energy is given off as heat.
� Heat- energy that is in the process of flowing from a warmer object to a cooler object.
(represented by the symbol q)
� When a warmer object looses heat, its temperature decreases and when a cooler object
gains heat, its temperature increases.
Measuring Heat-
� Calorie (cal) - in the metric system, the amount of heat required to raise the temperature
of one gram of pure water by one degree Celsius (10C).
� When your body breaks down food, the reaction generates heat that is measure in calories.
A nutritional Calorie is actually 1000 calories. 1000 calories is known as a kcal.
� Joule (J) � the SI unit of heat.
� One joule = 0.2390 calories or one calorie = 4.184 joules.
