the atmosphere - fossil fuels Flashcards
what are fossil fuels?
non renewable. they will run out. formed over millions of yeats
how is coal formed?
from remainders of ferns and trees. if these die in marshy wetlands they don’t decompose due to lack of oxygen or acidic conditions. these both prevent bacteria from carrying out decomposition. over time plant remains covered with sediment and compressed. high temp + pressure creates coal
what is crude oil formed from?
plankton which are tiny plants and animals found in the sea. when these died, they settle in mud on sea bed. if oxygen not present they won’t decompose. over time they are compressed by sediment and by heat and pressure convert to crude oil
how is natural gas formed?
it is mainly the hydrocarbon methane. find natural gas near deposits of oil. it is formed from plankton.
what do all fossil fuels contain?
trapped carbon which was part of the carbon dioxide taken in by photosynthesis
