topic 8 fuels and earth science Flashcards
what boiling points do long hydrocarbons have
higher boiling points
how is crude oil separated into fractions using fractional distillation
crude oil is heated until most of it turns to a gas. the gases enter a fractioning column and the liquid bitumen is drained off at the bottom. column is hot at bottom and cooler at the top, long hydrocarbons turn into liquid and drain and the bottom, short at the top
why do long hydrocarbons have a higher boiling point
because the intermolecular forces are stronger
what are the properties of shorter hydrocarbons
easy to ignite, lower boiling points, gases at room temp
what are the properties of longer hydrocarbons
liquids at room temp, hard to ignite and have higher boiling points
what is viscosity
how easily a substance flows, long hydrocarbons have a high viscosity so are thick
what do incomplete combustion reactions produce
toxic carbon monoxide and soot
why is carbon monoxide dangerous
can combine with red blood cells and stop the blood from carrying oxygen around the body which can lead to coma fainting or DEATH
why is soot dangerous
makes buildings look dirty, reduces air quality an can cause or worsen respiratory problems
what does sulfur dioxide cause in the weather and why is it bad
mixes with the clouds to form dilute sulfuric acid which falls as acid rain, which cause lakes and rivers to be more acidic making plants and animals die, also kills trees, damages limestone buildings and stone statues and can also make metal corrode
why are nitrogen oxides harmful
contribute to acid rain and cause photochemical smog which can cause breathing difficulties, headaches and tiredness
what is cracking
breaking long unsaturated molecules into smaller unsaturated and alkane molecules which are more useful
why does cracking require a lot of energy
it breaks strong covalent bonds
what happened to all the CO2 in the atmosphere
absorbed by the oceans or locked up in fossil fuels and sedimentary rocks
