FRONT CLASSROOM A FC D E B IG H Please, join your groups and identify ONE important idea you learned last class. NATS 101 : “The World We Create” 01/21

UNIT 1: Energy Sources, Conventional or Alternative?

Energy Sources Renewable sources - 6% Non-renewable sources - 94% –Of which 85.3% comes from Fossil Fuels (Hydrocarbons)  Combustion Close to 40% comes from Petroleum Limited Supply but High Demand!

WHO HAS THE OIL AND WHO USES IT?

What possible consequences: Economic Social Political concerning petroleum use are suggested by these comparisons? (at least one of each) Think of current and future issues associated with the distribution of oil and its use. Think, for example: What may happen as China develops? What could happen if the US loses access to Middle East reserves? ETC Who has it? Who Wants it? Then, let’s see what the data implies: You have 10 minutes Select a note taker and a spokesperson

By the end of the class, you should be able to:  Explain why petroleum is a valuable fossil fuel;  Given a set of chemical compounds, predict which of them will produce more energy during combustion based on their chemical composition; Today: Why Petroleum? C 4 H 10 C 2 H 6 O C 2 H 6 C 2 H 4 O 2

Why Petroleum? In your groups discuss: –Why don’t we all drive electric vehicles if there are so many issues associated with using petroleum as a source of energy?. You Have 2 Minutes

The Reasons Poor performance (Heavy, needs to be recharged). Compare Electrical batteries supply energy at a rate of 6500 joules (J) per second (6500 Watts = 6.5 kW) 1 Liter (1 L) of gasoline transfers 34,000,000 J per second when you burn it 34 Megajoules/s= 34 MW 1 Liter/s ~ 5,200 times faster Power Energy

The Reasons A large 2000 MW power station = 59 pumps Petroleum is a highly concentrated energy source! Why? Where is the energy coming from?

Hydrocarbons are combustible. They react with oxygen in a Combustion Reaction. The Chemistry of Petroleum Products Carbon Dioxide Water ENERGY Hydrocarbon Oxygen Reactants

Heat of Reaction EpEp CH O 2  CO H 2 O CH O 2 Net Energy Released = -804 kJ = q rxn 4 x x 249 C + H + H + H + H + O + O + O + O Dissociation Energy needed to break bonds. CO H 2 O x400 – 4x464 Formation Energy released when forming bonds.

Energy Graphs Products ENERGY RELEASED EXOTHERMIC Reactants Products ENERGY ABSORBED ENDOTHERMIC

Heat of Reaction Different substances produce different amounts of energy during Combustion Reactions. OctaneMethaneMethanol Energy released in kJ/mol (when 6.02 x molecules are burned) Methane CH 4 Methanol CH 4 O Octane C 8 H 18

Explain the Difference Give a possible explanation to the difference in the energy released when octane, methane, and methanol are burned. You have 5 minutes Methane CH 4 Methanol CH 4 O Octane C 8 H 18 E CH 4 (g) + 2 O 2 (g)  CO 2 (g) + 2 H 2 O(l) CH 4 O(g) + 3/2 O 2 (g)  CO 2 (g) + 2 H 2 O(l) C 8 H 18 (g) + 25/2 O 2 (g)  8 CO 2 (g) + 9 H 2 O(l)

The Reason During a chemical reaction some bonds are broken and some new bonds are formed. Breaking bonds requires energy Forming bonds releases energy NET RESULT? The more oxygen can combine with other atoms to form new bonds, the more energy will be released.

The Reason During a chemical reaction some bonds are broken and some new bonds are formed. Breaking bonds requires energy Forming bonds releases energy We are making fewer bonds with oxygen because one is already made. NET RESULT?

You Decide Consider the following two chemical compounds: Glucose C 6 H 12 O 6 Oleic AcidC 18 H 34 O 2 (main constituent of plant oils) Which of these two compounds will generate more energy when burned? Why? What are the implications for your body? Oleic acid is not only a larger molecule but is less oxygenated than glucose. Thus, it generates more energy when burned. 1 g the carbohydrate  17 kJ = 4.1 Cal 1 g of the fat  39 kJ = 9.3 Cal

Application In your groups, explore what happens when you combine each of the following substances with water: A) Ammonium Nitrate (NH 4 NO 3 ) B) Lithium Chloride (LiCl) – Add one cap of water at a time!! – Make sure to record observations! You Have 10 Minutes Generate an hypothesis in terms of bonds breaking and forming to explain any differences you observe. Compare in an energy graph the energy of reactants and products.

Exothermic LiCl(s) + H 2 O(l)  Li + (aq) + Cl - (aq) Lithium Chloride Water Lithium ionChloride ion LiCl + H 2 O PE Li + (aq) + Cl - (aq) Reactants Products ENERGY RELEASED Total energy is CONSERVED Strong Interaction with H 2 O

Endothermic NH 4 NO 3 (s) + H 2 O(l)  NH 4 + (aq) + NO 3 - (aq) Ammonium Nitrate Water Ammonium ion Nitrate ion NH 4 NO 3 + H 2 O PE NH NO 3 - Reactants Products ENERGY ABSORBED Total energy is CONSERVED

Homework Homework (Due 01/26/10) IMPORTANT CHECK D2L FOR THE ASSIGNMENT AND DETAILED INSTRUCTIONS (CONTENT SECTION) Also Check the Support Reading