Option C, continued Energy

Discuss the use of different sources of renewable and non-renewable energy. List 5 renewable or “green” energy resources. Solar Energy Wind Energy Biomass Hydropower Geothermal Ocean Icons taken from http://energy4me.org/all-about-energy/what-is-energy/energy-sources/

Discuss the use of different sources of renewable and non-renewable energy. Discuss pros and cons of Geothermal Energy. One of the most widely used commercial forms of renewable energy. Efficiency ~23%, but overall cost-effectiveness is attractive. Be prepared to answer pro/con questions; see study guide p 143 for fossil fuel list and text p. 662 & p. 677 for some “greener” developments… and use “carbon neutral because plants absorb CO2 while growing” when describing benefits of biofuels, including ethanol.

Discuss the use of different sources of renewable and non-renewable energy. Discuss pros and cons of Solar Energy. Taken from http://energy4me.org/all-about-energy/what-is-energy/energy-sources/ Pros Cons Non-polluting Most abundant energy source available Systems last 15-30 years High initial investment Dependent on sunny weather Supplemental energy may be needed in low sunlight areas Requires large physical space for PV cell panels Limited availability of polysilicon for panels

C.2: Fossil fuels store energy from photosynthesis Many fossil fuels contain saturated alkanes. Explain how how this changed from carbon sources present in decaying organisms. ~C.1: State the equation for the combustion of glucose. C.4: State the equation for photosynthesis.

Crude oil fractions and their uses Label the following diagram (skip 3) 1 What happens to crude oil here? 2 Top = “Bottled gas” 4 = Gasoline/petrol 5 = Naphtha = used to make chemicals 6 = Kerosene; aircraft fuel 7 = Diesel fuel (cars & trucks…& also trains) 8 = Fuel oil (for ships & power stations) 9 = Residue/bitumen (surfacing roads/roofs) See https://www.youtube.com/watch?v=JZdvsQzOKuk

Explain how the fractionating process works—what happens inside the column?

Write equations for cracking Long chain alkane, CnH2n+2, can not break into two alkanes: looking at it backward, CxH2x+2 + CyH2y+2 would give CzH2z+4 X Thus, cracking an alkane always produces exactly one shorter-chain alkane and any number of shorter-chain alkenes.

Explain the significance of the octane rating & how to increase the value Measures the fuel’s resistance to auto-ignition (cause of “knocking”) Catalytic reforming to a structural isomer with greater branching (but same molecular formula; ex. hexane -> 2,2-dimethylbutane). Catalytic reforming producing an arene/aromatic/phenyl group plus hydrogen (ex. heptane -> methylbenzene + 4 H2) Also note that smaller chain lengths have greater octane ratings.

Work backwards to understand “syngas” (synthesis gas) Goal = obtain clean alkane liquids, CnH2n+2 n CO + (2n + 1) H2  CnH2n+2 + n H2O Reactants are the “syngas” components, CO and H2, and are obtained from dried coal: C + H2O -> CO + H2 Overall effect is to adjust the carbon-to-hydrogen ratio.

Refresh yourself on C.3 Define/explain fission & fusion in terms of binding energy per nucleon; Note section 36 in Data Booklet and title of y-axis. What is significant about iron-56? Ex. Helium nucleus (no electrons), aka the alpha particle, is lighter than the sum of its parts. The nucleus is more stable by such a large energy difference that the mass is meaningful, too. Difference in mass divided by 4 particles (2 p & 2 n) = binding energy per nucleon.

Refresh yourself on C.3 Solve nuclear equations – make sure mass numbers add across correctly as well as atomic numbers add across correctly. OK to balance using multiple neutrons. Solve the fission chain reaction for U-235, given products strontium-90 and xenon-136. Review half-life calculations Absorption spectra used to analyze composition of stars, especially H & He. Concern = nuclear waste storage & use as weapons

C.4 Solar Energy What molecular structure allows absorption of sunlight, powering photosynthesis? purpurin chlorophyll

C.4 Write the equation for the fermentation of glucose into ethanol. Hint: 2 molecules of ethanol are produced, and 2 molecules of something else.

C.4 State one similarity and one difference between vegetable oil and diesel fuel. Similar energy content. Vegetable oils are too viscous to use in internal combustion engines. (This is the motivation for transesterification -> shorter chains w/ lower molar masses have less IMF and are thus less viscous.)

C.4 Know the transesterification equation completely, including NaOH catalyst.

C.5 Environmental Impact – global warming Refresh yourself on this—read through page 147 of the Study Guide for an efficient synopsis. Recall that increased acid concentration = lower pH (where each decrease of 1 in pH is a 10x increase in acid concentration).