C1.4-C1.7 Flashcards
What is a hydrocarbon?
A chemical that contains only carbon and hydrogen.
What is crude oil?
A mixture of hydrocarbons with different chain lengths.
How is crude oil formed?
Formed from the remains of animals and plants in the sea that were buried under sand and rocks. Over millions of years, the heat and pressure, in the absence of air and oxygen, convert the animals and plants to oil. Reservoir rock (porous) traps the oil here. Gas is also produced.
What is the smallest alkane?
Methane
How many bonds does carbon and hydrogen have in an alkane?
Carbon-4 bonds
Hyrogen-1 bond
What are the advantages and disadvantages of using fossil fuels to create energy?
Advantages:
Easy available- found all over the world, technology already built and running
Produce lots of energy
Stable- low chances of accidents (v something like nuclear)
Easily transported and stored
Low cost
Disadvantages: Greenhouse gases produced during combustion-contributes to greenhouse effect-global warming Non-renewable Prices rising- due to diminishing stores Pollution- bad impact on all life -Oil spills- bad impact on aquatic life
What are the advantages and disadvantages of using bio fuels to create energy?
Advantages: Easily sourced Renewable Sustainable Relatively carbon neutral
Disadvantages:
Currently expensive to produce
Potential for food shortages/price of food to increase- land being used to grow raw materials for biofuels instead of food
-ethical? -fuel over food?
Potential for water shortages- uses lots of water to grow so many crops
What is a biofuel?
A fuel that comes from a biological source (anything that is living)
What are 2 examples of biofuels?
Bio-diesel, Bio-ethanol
How are biofuels relatively carbon neutral?
The plants used to make biofuels absorb carbon dioxide from the atmosphere as they grow
When they are burnt as fuels, they release this carbon dioxide back into the atmosphere as a product of combustion
-would be carbon neutral BUT carbon dioxide is released into the atmosphere during the production of machinery used to make the biofuels
Are most hydrocarbons in crude oil alkanes or alkenes?
Alkanes
What is the general formula for knowing the number of carbon atoms and hydrogen atoms in an alkane?
H=2C+2
Are alkanes single or double bonded?
Does this mean that they are saturated or unsaturated?
Single
Saturated
Are alkenes single or double bonded?
Does this mean that they are saturated or unsaturated?
Double
Unsaturated
What are the first 5 alkanes?
Methane Ethane Propane Butane Pentate
What is a renewable resource?
A resource that is finite, and is being used up faster than it can be made. This means that eventually there will be no more of this resource left.
What is the relationship between the size of a molecule and its boiling point?
Why is this?
Smaller molecules- Lower boiling points
Larger molecules- Higher boiling points
The larger a molecule, the more intermolecular forces exist. The larger the amount of intermolecular forces, the more energy is needed to overcome them.
What 3 characteristics of hydrocarbons do we care about?
Boiling & condensing point
Viscosity (lower=less viscous)
Volatility-how easily something evaporates
Why are longer molecules less viscous and harder to pour?
The longer molecules get tangled more easily. (Analogy of hair/headphones)
When you increase the chain length of a hydrocarbon, what happens to the volatility?
Why?
Decreases
The longer the hydrocarbon, the harder it is for molecules to randomly evaporate.
What is the process of fractional distillation to separate the different sized hydrocarbons from crude oil?
A tall column is placed over the crude oil, with several condensers at different heights.
The crude oil is heated highly at the bottom of column, is cool by the top
Longer hydrocarbons condense nearer the bottom, and are siphoned off into their different containers
Smaller hydrocarbons with lower boiling points condense higher up, the shorter they are
What different fuels are extracted from crude oil?
Bitumen Oil Diesel Kerosine Naptha Petrol Refinery gas
What is produced from the complete combustion of a hydrocarbon fuel?
Carbon dioxide
What is produced from the incomplete combustion of a hydrocarbon fuel?
Carbon monoxide
+ particulates
What is the word equation of the complete combustion of a hydrocarbon fuel?
Hydrocarbon+oxygen–water+carbon dioxide
What is the word equation of the incomplete combustion of a hydrocarbon fuel?
Hydrocarbon+(less) oxygen–water+carbon monoxide+carbon (particulates)
What is test for carbon dioxide?
Lime water going cloudy
What is the cause of acid rain?
Sulfur dioxide
What is acid rain?
Rainfall made acidic due to atmospheric pollution that causes harm to the environment, buildings and animals
How does acid rain occur?
Most hydrocarbon fuels naturally have sulfur compounds
Combustion- oxidizes to make sulfur dioxide
Dissolves in water to create an acidic solution
Cause of acid rain
What are some of the dangers of acid rain?
Causes lakes to absorb aluminium that passes through them- Makes the water toxic to aquatic creatures
Releases aluminium into the soil-Makes it hard to take up water
Erodes buildings, peels paint, makes statues look worn
What is meant by complete combustion?
When all the carbon atoms in the reaction are consumed (paired with another atom)
What is meant by incomplete combustion?
When not all the carbon atoms in the reaction are not consumed (paired with another atom)
How are harmful waste gases from chimney’s turned into a useful product?
Treated with powdered limestone
Sulfur dioxide+powdered limestone–calcium sulfate
Calcium sulfate used to make plasterboard for interior walls of buildings
How is carbon monoxide harmful to us?
Binds to haemoglobin
Reduces the capacity for blood to carry oxygen- starves body of oxygen
What are the effects of combustion on the environment?
Releases green house gases Contributes to green house effect Global warming Rise in sea levels Loss of habitat for many animals Disturbed weather patterns Flooding Air pollution causes respiratory diseases
What is the carbon cycle?
Atmospheric carbon dioxide
Growing plants and algae use carbon dioxide in photosynthesis for food
Burning plant material releases carbon dioxide back into the atmosphere
What is cracking?
The process where long hydrocarbons are broken up into smaller ones by breaking a carbon-carbon bond
What are the benefits of cracking?
Large hydrocarbons are inefficient, hard to ignite and don’t flow easily
Smaller hydrocarbons are more useful and are in higher demand
What is the process of cracking?
Fractions containing hydrocarbons
vaporized
passed over a hot catalyst
breaks chemical bonds in molecule
What kind of chemical reaction is cracking?
A thermal decomposition reaction
What is the test for unsaturated molecules?
Bromine water
Orange–colourless
What is a saturated molecule?
A molecule with only single bonds
What is an unsaturated molecule?
A molecule with one or more double bonds
Are alkanes saturated or unsaturated?
Do they have double bonds, or single?
Saturated
Single
Are alkenes saturated or unsaturated?
Do they have double bonds, or single?
Unsaturated
Double
What are the first 5 alkenes?
Methene Ethene Propene Butene Pentene
What is the formula for the number of hydrogen atoms and carbon atoms in an alkene?
H=2C
What are the uses for alkenes?
Used to make polymers Used to make ethanol Can be used as fuel Paraffin wax Cooking
What is a monomer?
One molecule on its own
What’s a polymer?
Lots of monomers joined in a chain
paperclip analogy
What’s polymerization?
The process of chemically reacting monomers together to form a polymer chains or 3D networks
Where do polymers get their properties from?
Their structure
What are different examples of polymers and their uses?
PTFE- Goretex (sweat can get through tiny holes in fabric but water can’t)
PVC-Plastic windows, gutters
LDPE-Shopping bags
HDPE-Garden furniture
What does LDPE stand for?
Low density polyethene
What does HDPE stand for?
High density polyethene
Changes in what conditions resulted in the different properties of LDPE and HDPE?
Temperature
Pressure
Catalyst
What are the properties of LDPE?
Why?
Less dense than HDPE
Flexible
Has ‘branches’ coming off of each strand- can’t get close to each other
What are the properties of HDPE?
Why?
More dense than LDPE
Strong
Rigid
Has no branches- can be tightly packed in
Do polymers break down?
No
What are the three ways to dispose of polymers?
Landfill
Incineration
Recycling
What are the problems with using landfills to dispose of polymers?
Produces unstable land- sinkholes
Eye sore
Ruins the environment in that place
What are the problems with using incineration to dispose of polymers?
Burning plastic release toxic fumes
Bad for the environment
What are the problems with using recycling to dispose of polymers?
Expensive
Not always the most efficient method
What kind of molecules are the alcohols?
Organic
What is an organic molecule?
A molecule made up of
Oxygen
Carbon
Hydrogen
What are the first 5 alcohols?
Methanol Ethanol Propanol Butanol Pentanol
What are the two ways of producing ethanol?
Fermentation
Hydration
What is the process of fermentation?
Is it renewable?
Glucose+yeast (warm 20-30)– Ethanol+Water+Carbon dioxide
What is the process of hydration?
Is it renewable?
Ethene+steam(300)+phosphoric acid(catalyst)–Ethanol
No- it uses ethene which is produced from crude oil
What are the properties of fermentation and hydration?
Fermentation: Renewable Batch process Slow Impure product Relatively carbon neutral
Hydration: Non-renewable Continuous Fast Pure product Uses catalyst
What is the catalyst used in hydration?
Phosphoric acid
What industry is fermentation used to produce ethanol for?
Drinks
What industry is hydration used to produce ethanol for?
Industrial fuel
Antibacterial products
Which is better, batch production or continuous production?
Continuous production
Is vegetable oil high in saturated or unsaturated fats?
Unsaturated
Is butter high in saturated or unsaturated fats?
Saturated
What does immiscible mean?
Won’t mix with each other
Are water and oil immiscible?
Yes
What’s an emulsifier?
Food additives with a hydrophobic end and a hydrophilic end, that binds immiscible things together to form an emulsion
How do emulsifiers work?
Emulsifiers have two ends, a hydrophilic head and a hydrophobic tail.
The hydrophilic end binds to water
The hydrophobic end binds to oil.
What is a common emulsifier?
Washing up liquid
What is a common emulsion?
Mayonaise
What is hydrogenation?
Turning unsaturated hydrocarbons into saturated hydrocarbons
What is the word formula of hydrogenation for ethene?
Ethene+Hydrogen+(Nickel catalyst + 60)–Ethane
How are vegetable oils extracted?
Plant material is crushed and pressed to squeeze the oil out
If this is too difficult (sunflower oil), the plant material is dissolved in a solvent
Oil dissolved, solvent removed by distillation, impurities removed
What are the uses of vegetable oil?
Fuel- biodiesel
Cooking
Food
What are molecules of vegetable oil made of?
Glycerol + fatty acids
3 carbon atoms connecting to long chains of fatty acids
What is an example of a saturated oils/fats?
Lard
What is an example of an unsaturated oil?
Sunflower oil
What are monounsaturated fats?
Fats with 1 double bond in each fatty acid
What are polyunsaturated fats?
Fats that have many double bonds
