7 - Organic Chemisrty Flashcards
What is a finite resource? (COH OC Ch)
if we continue using it then it will one day run out.
Where do we find Crude Oil? (COH OC Ch)
In rock
How is crude oil formed? (COH OC Ch)
Over millions of years the remains of sea creatures called plankton which were buried in the mud.
What is crude oil made of in terms of structure? (COH OC Ch)
a mixture of molecules called hydrocarbons
What is the molecular formula for methane? (COH OC Ch)
CH4
one carbon atom covalently bonded to four hydrocarbons
What are hydrocarbons? (COH OC Ch)
molecules made up of hydrogen and carbon atoms only
What are the alkanes? (COH OC Ch)
Methane, Ethane, Propane and butane
What do we call hydrocarbons like methane and ethane? (COH OC Ch)
alkanes
What is the general formula of alkanes? (COH OC Ch)
CnH2n+2
What type of molecules are alkanes and why? (COH OC Ch)
becuase the carbon atoms are fully bonded to hydrogen atoms
how many carbon atoms does propane have? (COH OC Ch)
3
How many carbon atoms does butane have? (COH OC Ch)
4
What does viscosity tell us? (COH OC Ch)
the thickness of a fluid.
A high viscosity means that the fluid flows slowly
What happes to the viscocity as the size of the hydrocarbon molecules increase? (COH OC Ch)
as the size increases, the viscosity also does. Long chain hydrocarbons are extremely viscos
What does flammability tell us? (COH OC Ch)
how easily something combusts
What happens to the flammability of hydrocarbons as they increase in size? (COH OC Ch)
short chain hydrocarbons are extremely flammable. As the size increases the molecules are less flammable. Long chain hydrocarbons are very difficult to burn
What is the boiling point? (COH OC Ch)
the temperature at which a liquid turns to a gas.
What is happens to the boiling points of hydrocarbons as they increase in size? (COH OC Ch)
Short chain hydrocarbons have low boiling points. Very long chain hydrocarbons have very high boiling points.
What is released when hydrocarbon fuels are combusted? (CHC OC Ch)
release energy
What happens to hydrocarbons when they are combusting? (CHC OC Ch)
during combustion the carbon and hydrogen atoms in the fuel react with oxygen. The carbon and hydrogen are exidised. If the oxygen is unlimited, this reaction produces carbon dioxide and water which is called complete combustion.
What is the order in which you need to balance hydrocarbons? (CHC OC Ch)
Carbon, Hydrogen then Oxygen
What happens during fractional distillation? (FDHC OC Ch)
crude oil is separated into fractions, Fractions contain hydrocarbons with a similar number of carbon atoms
What is the process of fractional distillation? (FDHC OC Ch)
- crude oil is heated to a very high temperature which causes the crude oil to boil and all the hydrocarbons turn into gas.
- crude oil is fed into the fractional distillation column. This column is hotter at the bottom and cooler at the top
- the hydrocarbon vapours now rise up the column. Hydrocarbons condense when they reach their boiling point
- the liquid fractions are then removed
- the remaining hydrocarbons are the removed and condense when they reach their boiling points
Where are long chain hydrocarbons removed from in fractional distillation? (FDHC OC Ch)
removed from the bottom of the culumn
where are small chain hydrocarbons removed from in fractional distillation? (FDHC OC Ch)
they dont condense so they are removed from the top as gases.
Where are the fractions from fractional distillation used for? (FDHC OC Ch)
petrol and diesel are used to fuel cars
kerosene is used in jets fuel
heavy fuel oil is used to power ships
liquified petroleum gas is used in camping stoves
feedstock fractions are used for solvents, lubricants, detergents, polymers
What does feedstock mean? (FDHC OC Ch)
a chemical that is used to make other chemicals
What type of bond is between carbon atoms in alkanes(C OC Ch)
a single covalent bond
Why do we sometimes need to converts long chain hydrocarbons into shorter chain hydrocarbons? (C OC Ch)
becuase there is a large demand for short chain hydrocarbons for fuel.
How do you convert long chain hydrocarbons to shorter chain hydrocarbons? (C OC Ch)
cracking
What are the two products of cracking? (C OC Ch)
a shorter chain alkane and an alkene
What are the conditions for catalytic cracking? (C OC Ch)
we use high temperature and a catalyst which is used to speed up the reaction
What are the two types of cracking? (C OC Ch)
- catalytic
- steam
What are the conditions for steam cracking? (C OC Ch)
we use high temperature and steam
What are the alkenes? (C OC Ch)
ethene,
What type of onding between two carbon atoms are there in alkenes? (C OC Ch)
double covalent bonding
why are alkenes very important? (C OC Ch)
becuase they are used to make polymers and they are used as a staring material for other useful chemicals.
How reactive are alkenes compared to alkanes and why is this important? (C OC Ch)
alkenes are more reactive which allows us to test for alkenes
How do you test for alkenes? (C OC Ch)
- we use bromine water which is orange.
- when we mix our alkene with bromine water the bromine water turns colourless
What is the general formula for alkenes? (C OC Ch)
CnH2n
