8) Fuels & Earth Science Flashcards
What type of resource is crude oil?
Non-renewable
Where is crude oil found?
In rocks
What is crude oil used to produce?
Fuels and other important chemicals
What are hydrocarbons?
Molecules made up of only hydrogen and carbon atoms
What changes the properties of hydrocarbons?
Their differences in size
What are most of the compounds in crude oil?
Hydrocarbons
What is crude oil a mixture of?
Lots of different compounds that are not chemically combined
What is crude oil made from?
Fossilised plankton
What are groups of hydrocarbons with similar numbers of carbon atoms called?
Fractions
What is the process of separating crude oil into groups of hydrocarbons with similar numbers of carbon atoms?
Fractional distillation
What are hydrocarbons with lots of carbon atoms called?
Long-chain hydrocarbons
What are hydrocarbons with few carbon atoms called?
Short-chain hydrocarbons
What are the stages of fractional distillation?
Evaporation
Condensation
Collection
What can fractions be used to make?
Solvents
Detergents
Lubricants
What is the gases fraction used for?
Domestic heating and cooking
What is the petrol fraction used for?
Fuel for cars
What is the ketrosene fraction used for?
Fuel for aircrafts
What is the diesel oil fraction used for?
Fuel for trains and some cars
What is the fuel oil fraction used for?
Fuel for large ships and power stations
What is the bitumen fraction used for?
Surfacing roads and roofs
What are the crude oil fractions in order?
Gases Petrol Kerosene Diesel oil Fuel oil Bitumen
What differs with the size of hydrocarbons?
Melting points
What is a homologous series?
A series of compounds with the same general formula
How do the physical and chemical properties change in a homologous series:?
Similar chemical properties
Changing physical properties
What do the molecular formulas of neighbouring compounds in a homologous series differ by?
A CH2 unit
How do the properties of a larger hydrocarbon change?
Higher boiling point
Less flammable
Higher viscosity
What is the process that breaks down long-chain hydrocarbons into shorter chain molecules?
Cracking
What type of chemical reaction is cracking?
Thermal decomposition
What are the two ways of cracking?
Catalytic cracking
Steam cracking
What is catalytic cracking?
Vapourised heavy hydrocarbons are passed over the top of a heated alkene
What is produced in cracking?
Alkanes and alkenes
e.g. hexane –> butane + ethene
What is steam cracking?
Vapourised heavy hydrocarbons are mixed with steam in a high temperature environment
What is cracking?
Breaking down long-chain hydrocarbons into shorter more useful molecules
What do the equations for combustion of hydrocarbons depend on?
The amount of available oxygen
What does the combustion of hydrocarbons when there is good oxygen supply involve?
Energy release
Creation of carbon dioxide and water
What does incomplete combustion of hydrocarbons produce?
Carbon monoxide
Soot
Why can soot cause problems?
It can build up in appliances such as cars
What is produced when alkanes are burned without enough oxygen?
Carbon monoxide
What are properties of carbon monoxide?
Colourless
Toxic
Odourless
What happens when hydrocarbons burn in a confined space?
High temperatures cause nitrogen and oxygen to react
What does the reaction of nitrogen and oxygen form?
Toxic nitrogen oxides
What impurity is found in all fossil fuels?
Sulfur
What happens when sulfur burns?
It oxidises
What does burning sulfur produce?
Toxic gas sulfur dioxide
What can happen if sulfur dioxide is inhaled?
Respiratory problems
What is formed from the reaction of sulfur dioxide and water?
Sulfuric acid
What is a major component of acid rain?
Sulfur dioxide
What can be used as an alternative to petrol as fuels in cars?
Hydrogen fuel cells
What are advantages of using hydrogen over petrol?
Only waste product is water
No greenhouse gases emited
More energy per gram
What are disadvantages of using hydrogen over petrol?
Hydrogen must be stored at a high pressure
Hydrogen gas is explosive
Lack of places to refuel
What is the chemical reaction of burning hydrocarbons with a lack of oxygen?
2C + O2 –> 2CO
How long ago was the Earth formed?
4.6 billion years ago
What gas dominated the early atmosphere?
Carbon dioxide
What was littered across Earth’s surface for the first billion years?
Volcanoes
What did frequent eruptions of volcanoes form?
Release of carbon dioxide Nitrogen Water vapour Methane Ammonia
Why did the oceans form?
Water vapour condensed
What did the formation of oceans cause?
A significant reduction in atmosphere carbon dioxide levels
What was produced by reactions between dissolved carbon dioxide and seawater?
Carbonate precipitates
What was deposited as sediment?
Carbonate precipitates
What increased the atmospheric concentration of oxygen?
Photosynthesis
What does photosynthesis produce?
Glucose
Oxygen
What was the first photosynthetic organism?
Algae
When did the first organism begin to photosynthesise?
2.7 billion years ago
What did a higher oxygen threshold allow to form?
Complex life forms such as animals
What 3 factors caused atmospheric carbon dioxide to decrease?
Marine animals
Oceans
Photosynthesis
How did marine life cause atmospheric carbon dioxide to reduce?
They removed carbonates from the ocean to build shells and skeletons
What is the test for oxygen?
Insert a glowing splint into a test tube containing a gas
If gas is oxygen, splint will relight
What is the process of the greenhouse effect?
1) Sun emits short wavelength infrared radiation
2) Earth absorbs portion of radiation but longer wavelength is reflected back into the atmosphere
3) Greenhouse gases can’t absorb short wavelength radiation but can sbsorb reflected radiation
4) Gases re-radiate this as heat energy and some heads back towards Earth
5) This increases Earth’s surface temnperature
What human activites cause the atmospheric concentrations of gases to increase?
Burning fossil fuels
Agriculture
Deforestation
Landfill sites
How do landfill sites increase greenhouse gases?
Mounds of waste decompose
Decomposition releases methane
How does agriculture increase greenhouse gases?
Farm animals relsease methane during digestion
How does deforestation increase greenhouse gases?
Global rate of photosynthesis decreases
Less carbon dioxide removed from atmposhere
How does burning fossil fuels increase greenhouse gases?
Releases carbon as carbon dioxide
This carbon had been stored away for millions of years
What are 3 greenhouse gases?
Carbon dioxide
Methane
Water vapour
Why is it difficult to create accurate climate change models?
The global climate system is very complicated
How is misinformation spread on climate change?
Published in media
Some people have motives to downplay climate change
What are sources of misinformation on climate change?
Biased opinions
Overly simplistic models
What are potential consequences of climate change?
Melting polar ice caps Meteorological events Changes in water availability Changes in precipitation Food shortages
What does melting polar ice caps cause?
Rising sea leves
Some species will be less successful hunters
Coastal erosion
What could changes in water availability cause?
How species are distributed
What changes to precipitation could climate change cause?
Quantity
Timing
Distribution
How much of the Earth’s atmosphere is oxygen?
21%
How much of the Earth’s atmosphere is nitrogen?
78%
What gases make up Earth’s atmosphere?
Nitrogen Oxygen Argon Carbon dioxide Methane Water vapour Neon
What factors make a good fuel?
Cheap Low boiling point High volatility Ignties easily Low emissions
What is volatility?
How easily a compound evaporates
How do you test if a substance is pure?
Compare to a known pure fuel
Pure substance boils over a very small temperature range
What do plants use carbon to produce?
Sugars
Where are compounds with the lowest boiling point collected in fractional distillation?
The top of the column
What is the volatility of compounds with a low boiling point?
High
What are fossil fuels formed from?
Organic material that has been buried and compressed
What is coal formed from?
Plant deposits
What reaction occurs when fossil fuels are burnt?
Combustion reaction
What is one of the products of burning fossil fuels?
Carbon dioxide
What reacts with oxygen during the burning of fossil fuels?
Organic molecules formed by photosynthesis
