Fuels and Health Science Flashcards
(52 cards)
What are hydrocarbons?
Compounds that contain hydrogen and carbon atoms only
What is crude oil?
A complex mixture of hydrocarbons, contains molecules with rings or chains of carbon atoms, an important source of useful substances and finite resource
Where can crude oil be found?
Under sea and ground
What does finite mean?
It will to run out
How can crude oil be separated?
Fractional distillation
How does the process of fractional distillation work to separate crude oil?
Crude oil is vaporised before it enters a fractionating column, the fractionating column is hotter at the bottom than at the top, the vapours rise up and condense at different fractions depending on their boiling points and hydrocarbons with low boiling points will be tapped off the top of the column and hydrocarbons with high boiling points will be tapped off the bottom of the column
Why is crude oil separated?
Unseparated crude oil isn’t very useful but the separation product are very useful
What are refinery gas common uses?
Heating and cooking
Which fraction of crude oil is used as fuel in cars?
Petrol and diesel is also less commonly used
What is a common use of kerosene?
Aircraft fuel
What is diesel oil commonly used for?
Fuel for some cars and trains
Which fraction of crude oil is used for road surfacing and roofs?
Bitumen
What is fuel oil commonly used for?
Fuel for large ships and in some power stations
How do the hydrocarbons at each faction differ?
Boiling points, ease of ignition, viscosity and the number of hydrogen and carbon atoms their molecules have
Where in the fractionating column do hydrocarbons with highest viscosity condense?
Viscosity is how thick and sticky a substance is, the hydrocarbons with the highest viscosity are collected at the bottom of the fractionating column
What properties of hydrocarbons that are tapped from the top of the fractionating column?
Low boiling point, highly volatile, easily ignited and shorter carbon chains
What is a homologous series?
Series of compounds which: have the same general formula, similar chemical properties, differ by CH2 in molecular formula form neighbouring molecules and slight variation in physical properties
Which homologous series do products from crude oil mostly belong to?
Alkane homologous series
What are the only products when a hydrocarbon fuel undergoes complete combustion?
Water and carbon dioxide
Is energy given out when a fuel undergoes complete combustion?
Yes the reaction is exothermic
When does incomplete combustion occur?
There is an insufficient supply of oxygen and to ensure complete combustion occurs the reaction should be carried out with excess oxygen
What are the products of incomplete combustion?
Carbon particulate (soot), carbon monoxide and water
What are the problems with carbon monoxide?
Carbon monoxide is a toxic gas, it is colourless and odourless and if breathed in can cause death by preventing the red blood cells from carrying oxygen around the body
What are the problems with incomplete combustion?
Produces carbon monoxide which is toxic and can be fatal if breathed in and produces carbon particulates which cause globa dimming and respiratory problems