1. Energy and Chemical Change
Chapter 16
Energy and Chemical Change

2. Energy
Energy is the ability to do work or produce heat. Can you name some examples of energy that you observe in your everyday life?
Heat is a form of energy that flows from a warmer to a cooler object.
James Prescott Joule was the first person to make the connection between work and heat which ultimately lead to the Law of Conservation of Energy. Using a simple machine, Joule was able to calculate the amount of heat produced by mechanical energy. The amount of heat required for work done is called the Joule (J). It takes joules to move one kilogram of mass a distance of one meter in 1 second.

3. Types of Energy
There are 2 different forms of energy : Kinetic and Potential
Potential is due to the composition or position of an object.
Kinetic is energy of motion

4. Kinetic and Potential Energy on a Molecular Level
The potential energy is locked in the bonds that hold atoms together in compounds
The kinetic energy occurs when the chemical bonds separate
Bond Energy
(hehehehehe)

5. Chemical Potential Energy
The amount of energy stored in a substance. The atoms and type of bond present in the compound determine the chemical potential energy. In octane C8H18, the energy is related to the strength found between the carbon and hydrogen bonds. When the fuel is burned in an engine, the stored energy is converted to work in moving the pistons which ultimately moves the wheels and propels the car forward.
Diesel fuel (C12H23) has more Chemical Potential Energy than octane, and as a result, can achieve the same gas mileage as small economy octane powered cars.

6. Law of Conservation of Energy
The Law of Conservation of Energy states that the energy in the universe is constant. As energy changes from one form to another, there is no net gain or loss of energy. This explains why perpetual motion machines are a myth. As machines are set in motion, there is a heat loss due to friction and heat between mechanical parts and eventually the machine will come to a stop once its energy has been converted into other forms.
A car engine only converts about 37% of the energy in gasoline to mechanical energy to turn the wheels. The other % goes to energy in gasoline lost as heat. All the metal to metal contact in an internal combustion engine causes friction.

7. Measuring Heat
Because energy and heat go hand in hand, the flow of energy and the resulting change in temperature is measured in the metric system with joules. Also, a method of measuring heat and energy that is commonly used is the calorie- the amount of heat needed to raise the temperature of one gram of pure water one degree centigrade.
Another area the term calorie is used is with food. It takes 1000 calories to equal one food Calorie.
All of these terms are related and to satisfactorily complete this chapter, you will need the following equivalents memorized:
1000 calories = 1 Calorie = 1 kilocalorie
4.184 joules = 1 calorie
1000 joules = 1 kilojoule

8. Heat Problems Practice I
Convert 10 calories to joules
2. Convert 10 joules to calories
3. Convert 3000 joules to kilojoules
4. Convert 3000 calories to kilocalories

9. Heat Problems Practice I
5. Convert 3000 calories to Calories
6. Convert 3000 calories to kilojoules
7. Convert 3000 joules to kilocalories
8. Convert 3000 joules to Calories

10. Heat Problems Practice I
9. Convert 10 kilojoules to kilocalories
10. Convert 10 Calories to kilojoules
11. Convert 3000 calories/minute to joules/hour
12. Convert 10 kilojoules/minute to kilocalories/hour