Home > Chemistry > Chemistry 1A Part Deux: Lecture 31 Notes

Chemistry 1A Part Deux: Lecture 31 Notes

Overview

This is a 47 minute lecture on energy conversion.  We only have 8 more lectures here.  This lecture is basically an overview of alternative energy technologies.

Details

The energy we use in our daily lives comes at a cost.  Heat to work is not very efficient – 30%.  There is also PV work and redox work.

The sun is 92% hydrogen, 8% helium.  At the surface, 5800 K.  At the center, 10^7 K.  The activation energy for the fusion of two nuclei is 40GJ/mol or 4 x 10^7 kJ/mol

40 million K is needed to overcome the Coulomb repulsion.

Total wind power in the US is 4.3 x 10^10 W, about 2.3% of all US power.

Then she covers geothermal.

Nuclei smaller than Fe release energy when they fuse.  Those larger release energy when they fission.

Control rods absorb neutrons to control the rate of nuclear fusion.

Chemical Energy

Biomass

C6H12O6 + 6O2 = 6CO2 + 6H2o   -2991 kJ/mol

Petroleum

C8H18 + 12.5O2 = 8CO2 + 9H20     -5190

Natural Gas

CH4 + 2O2 = CO2 + 2H2O                   -801

Coal

C + O2 = CO2                                          -394

Light energy from the sun breaks the Coulomb attraction between an electron and the nucleus in semiconductor materials.  PV energy seperates charges and excites electrons into the conduction band.

Energy sources in the US in order: petroleum, natural gas, coal, nuclear, renewables: biomass, hydroelectric, wind, geothermal, solar

Fuel cells separate half reactions.

Review

Electronegativity: NOF Cl Kr

PV = nRT

Radiation: beta, alpha, gamma

E = hf

p = mv

U = PE = mgh

METT TC – mission enemy terrain troops time civilians

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