fossil fuels (in class) Flashcards
stores of carbon
biomass, atmosphere, ocean, lithosphere
how is carbon stored in biomass?
- as reduced carbon
- (photosynthesis reduces biomass)
how is carbon stored in the atmosphere?
oxidized carbon (CO2)
how is carbon stored in the ocean?
lots of reduced carbon (anaerobic breakdown)
how is carbon stored in the lithosphere (rocks)?
b/w oxidized and reduced carbon
oxidized carbon
process by which C gains bonds to oxygen
reduced carbon
process by which C gains bonds hydrogen
origin of oil and natural gas
marine
biological pump
- when plankton die, they get eaten, respire CO2, get eaten, respire CO2, etc.
- lipid rich remainders (cell walls and cell membranes) in sediment
- anaerobic bacteria break down dead matter
—> residue = origin of oil
ultimate source of energy in oil
SUN
coal origin
terrestrial
components of plants
cellulose + lignin
cellulose polymer =
glucose
lignin polymer =
aromatic molecules (benzene ring)
what happens when a plant dies?
- bacteria breakdown cellulose
- lignin = resistant = slower breakdown –> coal
ultimate source of energy in coal
SUN
biomass (type of carbon = ?)
reduced carbon
how is fuel energy stored and released?
- stored = chemical bonds
- released = combustion
enthalpy “ΔH”
heat content of a system
- @ constant P (atm)
exothermic
ΔH = (-)
- enthalpy products > reactants
exothermic
ΔH = (+)
- enthalpy products < reactants
bond dissociation energy
amount of energy to break one mol of gas –> radicals
stronger bond =
↑ bond dissociation energy
larger electronegativity difference =
larger enthalpy
