C1 Flashcards
What is an alkene and what is its formula?
Contain a double bond between two carbon atoms. This makes them much more reactive than alkanes. They are unsaturated.
AN UNSATURATED HYDROCARBON
CnH2n
What is an alkane and what is its formula?
Contain single c to c bonds. They are saturated.
A SATURATED HYDROCARBON CONTAINING SINLGE C-C BONDS
CnH2n+2
What does saturated mean?
Only contains single c-c bonds
What does unsaturated mean?
Contains at least one c=c double bond
What is crude oil?
A mixture of a very large number of compounds which are useful to us most of which are hydrocarbons with different boiling points
How do we separate crude oil?
Fractional distillation
Why is it possible to separate the fractions of crude oil by fractional distillation?
The compounds have different boiling point
What are the properties of the top of the column in fractional distillation?
Small molecules: •low boiling point •very volatile •flows easily •ignites easily
What are the properties of the bottom of the column in fractional distillation?
Large molecules: •high boiling point •not very volatile •doesn't flow easily •doesn't ignite easily
What is the definition a hydrocarbon?
Molecules containing only hydrogen and carbon atoms
What is the equation for incomplete combustion?
CH4+O2=CO+C+2H2O
What is the equation for complete combustion?
CH4+2O2=CO2+2H2O
Why does incomplete combustion occur?
there isn’t enough oxygen to react with
What does incomplete combustion produce?
Carbon monoxide, carbon and water
What effect does carbon monoxide have on humans?
it is poisonous and harmful. Is also a greenhouse gas
What is Sulphur Dioxide?
Compound which contains one sulphur atom and two carbon atoms in each molecule and is present in acid rain.
How are oxides of nitrogen produced when fuels burn in car engines?
Nitrogen and oxygen react together in the high temperature of the car engine to form nitrogen oxide
What are biofuels?
Anything which comes from a living organism
OR
A fuel obtained from a grown crop such as ethanol from sugar cane
List 4 disadvantages of biofuels
1) using fuel instead of food means less food is produced (leads to higher prices)
2) Both fossil fuels and biofuels produce CO2
3) Energy used for machinery may be more than what is produced.
4) Decrease in biodiversity
What is Cracking?
Process of breaking large molecules into smaller more useful ones by heating or using a catalyst
List the stages in cracking
*heat to vaporise the long alkanes
*vapours are then passed over a hot catalyst
(or mixed with steam at a very high temperature)
*thermal decomposition then occurs
What is a catalyst?
Substance that speeds up a reaction without being used up in the reaction
What are the products of cracking?
Cracking always produces two types of molecule: an alkane and an alkene
What is a polymer?
Material whose molecules are made up of many monomers
What is polymerisation?
Is when many monomers join together to form a long chain called a polymer
What two polymers would be made from the monomers ethene and propane?
poly(ethene) and poly(propane)
What name do we give the mouldable polymers that are made from alkenes?
Plastics
What is the issue with disposing of plastics?
They are not biodegradable
State the two ways in which ethanol can be produced
From ethane- ethane+steam=ethanol
From sugars-glucose=ethanol+carbon dioxide
What are some of the main differences between the two ways to produce ethanol?
From ethane, cracking is used, there are no waste products but it is a non-renewable source
Wheras, from sugars, fermentation is used, CO2 is a waste product but it is renewable as the materials for fermentation can grow again
What is an emulsifier?
Material that enables a stable mixture to be formed between two liquids that would normally seperate
How do emulsifiers work?
The emulsifier stabilises the mixture
What is the process called where vegetable oils are hardened?
Hydrogenation
What does hardening vegetable oils do to its properties?
gives them a higher melting point, making them solids at room temperature
Describe the conditions needed for hydrogenation
oils can be reacted with hydrogen in the presence of a nickel catalyst at 60 degrees Celsius
What is an element?
substance that contains only one type of atom
What would you find in the nucleus of an atom?
protons and neutrons
What does atomic number mean?
the number of protons in the nucleus of an atom
What is the definition of mass number?
The total number of protons and neutrons in the nucleus of the atom
How do you find the number of electrons in an atom?
look at its atomic number on the periodic table
How do you find the number of neutrons in an atom?
look at its mass number on the periodic table and subtract the atomic number from it
What is the charge and relative mass of an electron?
negative
1/2000
What is the charge and relative mass of a proton?
positive
1
What is the charge and relative mass of a neutron?
Neutral
1
How do electrons arrange themselves in shells?
2,8,8
What is the link between elements in a particular group of the periodic table?
The group they are in is the same number of electrons which are on the outer shell
What is an ion?
is an atom that has acquired a charge by losing or gaining electrons to achieve a full outer shell
What happens when a metal and a non metal react in terms of electrons?
They react to form two oppositely charged ions
What is the chemical formula for limestone?
CaCO3
How is limestone obtained?
Quarrying
What process do carbonates undergo when heated?
thermal decomposition
What is produced when carbonates react with acid?
salt+water+carbon dioxide
How do you make cement?
limestone + clay
How do you make mortar?
limestone + clay = cement
cement + sand + water = mortar
How do you make concrete?
limestone + clay = cement
cement + sand + water + aggregate = concrete
What is an ore?
something which contains enough metal to make it economical to extract the metal
How are metals in the middle of the reactivity series extracted?
using displacement reactions (oxidation and reduction)
How can copper be extracted from low grade ores?
Either through phytomining or bioleaching then electrolysis or displacement
How can copper be extracted from copper rich ores?
Smelting then electrolysis or displacement
Describe phytomining
- Copper ions are absorbed by plant roots
- the plant is then burnt
- oxygen reacts with the copper ions creating copper oxide ( Cu+O=CuO)
- This compound remains in the ash produced and is then separated by electrolysis
Describe bioleaching
This involves using bacteria to extract copper. The bacteria breaking down the material will absorb copper compounds and the bacteria will then release these compounds called leachates. the solution is collected and electrolysis is used to separate them.
What is electroloysis?
process by which ionic compounds (must be a liquid) are broken down by passing and electric current through them. Electrodes are placed in a solution (one being positive and one negative) and the ions in the solution become attracted to the opposite electrode.
Why is extracting aluminium and titanium expensive?
They are more reactive than carbon so cannot be extracted with carbon in a blast furnace therefore the kroll process is used. This are many stages for this and lots of energy is needed making it expensive.
What do we call iron direct from the blast furnace?
molten iron
What is an alloy?
An alloy is a mixture of a metal with other metals to improve/alter its properties
What are the layers of the earth?
crust, mantle, core
What are tectonic plates?
a large piece of the earths crust that gradually moves across the surface of the mantle
What is the composition of gases in our current atmosphere?
78% nitrogen, 21% oxygen
Why is the level of carbon now increasing in the atmosphere?
Our early atmosphere was almost purely carbon dioxide. However when the earth cooled and life began sedimentary rock lock the carbon away as limestone and dead organisms were trapped. When we burn these all of the trapped CO2 is being released.
