1. Energy and Hydrocarbons
Chapter 9
Energy and Hydrocarbons

2. Chapter Outline Background & Energy from Fuels
Alkanes: Backbone of Organic Chemistry
Alkenes and Alkynes: Reactive cousins of Alkanes
Cyclic Hydrocarbons
Petroleum
Natural Gas
Coal
Methanol (Gasohol)

3. Define some terms
Energy is a common idea that ran through the first half of the class.
What is Energy?
What is Heat?
What is Temperature?
What is the difference between heat and temperature?
What are the ‘units’ of each measurement?
Exothermic vs. Endothermic

4. Energy Energy is defined as ‘the capacity to do work’
What does this mean to you?
Energy: Capacity to do work or to transfer heat!

5. Types of Energy Kinetic Energy – Energy of Motion
Ek = ½ mv2 m= mass (kg)
v = velocity (m/s)
Ek = Joules

6. Potential Energy – Stored energy based on the position of one object with respect to another
Ep = m *g* h m = mass (kg)
g = gravitational constant
= m/s2
h= distance above reference

7. Example
What is the kinetic Energy of a bowling ball moving at a velocity of 1.5 m/s? (Mass of bowling ball = 7.5 kg)
Ek = ½ mv2

8. Units of Energy Heat can have the following units
Joules (J) = 1 kg*m2/s2
Kilojoules(kJ)
calories (cal) = Joule
Kilocalories (kcal) = 1000 calories
Dietary Calories = Calories (Cal) = 1 kcal
Erg
BTU
Foot-pounds

9. Energy
Calculate the amount of potential energy of a 1 kg book raised about 6 ft (~2 meters) into the air.

10. First Law of Thermodynamics
Energy is neither created nor destroyed.
The Energy is said to be “transferred or transformed”!
What happened to the energy of the book?

11. Heat vs. Temperature
Some of the energy was transformed to sound energy and some converted to heat!
WHAT IS HEAT?
Before we consider heat … let’s look at temperature!

12. Temperature Think back to global warming
vibrating molecules caused an increase in temperature
Temperature – average kinetic energy of molecules in a substance.

13. What is Heat? Heat is the total amount of energy in a substance
In other words – its the amount of thermal energy that a system contains.
Heat Energy = (specific heat)*(amount of substance)*(Temperature)
What’s the difference between Heat and Temperature?
Think of this Example –
A drop of boiling water and 4 liters of boiling water. Which one has more energy?

14. What is a calorie? Based on the work of James Joule (late 1800’s)
One calorie = amount of heat required to raise 1 gram of water 1 degree Celsius.
One calorie = Joules

15. Units of Energy Heat can have the following units
Joules (J) = 1 kg*m2/s2
Kilojoules(kJ)
calories (cal) = Joule
Kilocalories (kcal) = 1000 calories
Dietary Calories = Calories (Cal) = 1 kcal
Erg
BTU
Foot-pounds

16. Some ‘exercises’ 1. How many joules are in 425 Cal?
2. How much energy is required to raise 1 gram of water 1oC?
How much energy is required to raise 1000 grams (1 kg) of water from room temperature (25oC) to boiling (100oC) ?

17. Exothermic vs. Endothermic
Draw energy diagrams for the following processes.
Dissolving of Urea in water
Dissolving of Ethanol in water

18. 9.1 Energy from Fuels
Source of Energy used in the United States
Most of our energy comes from Fossil Fuels
(Petroleum, Coal, Natural Gas)

19. Combustion of Natural Gas
Natural Gas is mostly Methane
Consider the complete combustion of methane
____ CH4 + ____ O2 -> ____ CO2 + ____ H2O
Methane Oxygen Carbon dioxide Water
Is Energy Produced? How much?

20. What determines if Energy is released or absorbed in a chemical reaction?
Bond Energies!!

21. BOND ENERGIES