Organic chemistry Flashcards
(29 cards)
what is a hydrocarbon
a compound of only hydrogen and carbon
What is homogolous series
series of compounds with the same general formula and similar properties
what is a functional group
a group of atoms responsible for the chemical reactions of a compound
what are isomers
compounds with the same molecular formula with different structural formula
How to name compounds with prefixes and suffixes
PREFIXES
1 carbon = meth-
2 carbon = eth-
3 carbon = prop-
4 carbon = but-
5 carbon = pent-
6 carbon = hex-
SUFFIXES
alkane = -ane (single bond)
alkene = -ene (double bond)
alcohol = ol (OH)
How to classify reactions of organic compounds
Addition = 1 product
Substitution = 2 products
Combustion = reaction of fuel with oxygen
Describe crude oil
• mixture of hydrocarbons
• has rings and chains of carbon atoms
• it is an important source of useful substances such as fuel
• a finite resource
how the industrial process of fraction distillation separates crude oil into fractions
• oil heated in fractioning column and oil evaporates and condensed as different temperatures
• The hydrocarbons can be sep4rated into fractions, which contain molecules with a similar number of carbon atoms
• The fractioning column works continuously
• heated crude oil is piped at the bottom
• vaporized oil rises up the column, and the fractions are tapped off at the level they condense
What are the names and uses of the fractions obtained from crude oil
REFINERY GAS
• domestic heating and cooking
GASOLINE/PETROL
• Fuel for cars
KEROSENE
• fuel for planes
DIESEL
• Fuel for some cars and trains
FUEL OIL
• Fuel for large ships and some power stations
BITUMEN
• Surface roads and roofs
What is the trend in colour, bpt and viscosity of the main fractions
• shorter molecules, lower bpt
• shorter molecules, less viscous
•colours are darker at the bottom of fractions - longer molecules
What is fuel
a substance that releases heat energy when burned
what are the possibilities products of complete and incomplete combustion of hydrocarbons with oxygen in the air
COMPLETE combustion
• CO² and H²O are produced
INCOMPLETE combustion
• solid particles of soot (carbons), sunburnt fuel, carbon monoxide
Why is carbon monoxide poisonous
• it prevents red blood cells to carry oxygen around the body
• can lead to breathing difficulties and eventually death
What happens in a car engine
• The temperature is high so nitrogen and oxygen react to form oxides
• either nitrogen monoxide OR nitrogen dioxide
explain how the combustion of some impurities in hydrocarbon fuels produces sulfur dioxide
• most fuels contain carbon and/or hydrogen and also contain some Sulphur
• so when fuels are burnt the sulfur is oxidized to produce sulfur dioxide
how does sulfur dioxide and oxides of nitrogen contribute to acid rain
• sulfur dioxide and oxides of nitrogen in the atmosphere react with rain water to create H+ ions
• when rain falls the acid can corroded rocks and buildings
the acid acne alter pH in soil or rivers which can affect ecosystem
• acid rain corroded limestone, which damages buildings and statues
describe how long chain allanes are converted to alkenes and shorter chain alkanes by cracking
• hydrocarbons can be cracked to produce smaller more useful molecules. This involves heating the hydrocarbons to vaporize them
• vapours are:
- passed over a hot catalyst (silica or alumina)
- mixed with steam and heated to a very high temperature (600-700°C) so thermal decomposition occurs
Why is cracking necessary
• demand fpr smaller chained alkanes are much higher than longer chained alkanes
• supply for longer chained alkanes is higher than smaller chained alkanes
• therfore cracking produces smaller chained alkanes- meets demand
General formula for alkanes
CnHn+2
Why are alkanes saturated hydrocarbons
• don’t have double bonds
• Carbons are saturated because each carbon has 4 single bonds
4.22
what is the functional group of alkenes
C=C
General formula for alkenes
CnH2n
Why are alkenes unsaturated hydrocarbons
contains one or more double bonds
