Chemistry C9-C11 Flashcards
(31 cards)
what are functional groups
Functional groups are a collection of atoms that impact the reactions of an organic compound.
how is crude oil formed
When animals and plants (such as plankton) died over millions of years ago in the oceans, they fell to the bottom of the ocean and decayed anaerobically in mud over millions of years under high pressure and temperature. This organic matter, called ancient biomass, turned into crude oil and became stored within rocks.
what is crude oil made of
Crude oil is a mixture of lots of different compounds that are not chemically combined,
Most of the compounds in crude oil are hydrocarbons(organic compounds made of carbon and hydrogen).
what happens if you change the size of a hydrocarbon
A hydrocarbon’s size affects its properties. A hydrocarbon’s properties affect how useful it is as a fuel. The most important properties are:
.Boiling point, a hydrocarbons with longer chains have higher boiling points
.Flammability, hydrocarbons with longer chains are less flammable
.Viscosity, hydrocarbons with longer chains have higher viscosity (i.e. they are thicker and flow less easily)
what are Alkanes
In Alkanes, carbon atoms bonded to four atoms (hydrogen or carbon), We call them saturated hydrocarbons as all their bonds with other atoms are single bonds, Alkanes have quite low reactivity but they combust quite well this makes them useful as fuels,Alkanes have the general formula CnH(2n+2)
what are Alkenes
Alkenes are hydrocarbons with the functional group C=C. This means that Alkenes have a carbon-carbon double bond, Alkenes are unsaturated hydrocarbons because they contain a double bond between two of their carbon atoms (C=C), Alkenes are a homologous series with the general formula CnH2n, the presence of the C=C functional group means that Alkenes have greater reactivity than Alkanes.
what are 2 uses of Alkenes
Starting materials for chemicals like ethanol,
Being combined to make polymers
what are addition reactions in Alkenes
Addition reactions are normal for alkenes. In these reactions, the C=C bond opens up and allows carbon atoms to bond with new atoms.
What does it mean for a compound to be saturated
Saturated means something has bonded as many time as possible. No more bonds can be made, in saturated compounds all the bonds are single bonds throughout the whole structure.
What doe these prefixes mean:
.Meth
.Eth
.Prop
.But
.Pent
.Hex
.Hept
.Oct
.Non
.Dec
Meanings:
. 1
. 2
. 3
. 4
. 5
. 6
. 7
. 8
. 9
. 10
What suffex do Alkanes all ways end in
ane
What is fractional distillation used for and how does it work
fractional distillation is used to separate crude oil into groups of hydrocarbons with similar numbers of carbon atoms, We call these groups of hydrocarbons “fractions”,
Different-sized hydrocarbons have different boiling points fractional distillation separates hydrocarbons using their different boiling points
what are organic compounds
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon’s ability to catenate (form chains with other carbon atoms
what happens when Alkanes are combusted without enough oxygen
carbon monoxide can be created:
2C + O2 → 2CO
Carbon monoxide is a gas with the following properties:
.Colourless
.Toxic
.Odourless
what happens when hydrocarbons are combusted with enough oxygen
The combustion (burning) of hydrocarbons when there is a good air supply involves:
.The release of energy
.The oxidation of carbon and hydrogen to create carbon dioxide and water
what are 3 properties of Heavy Fractions of Crude Oil
They don’t ignite easily
They have high boiling points
They have higher viscosity
what is cracking
Cracking is the process that breaks down long-chain hydrocarbons into shorter-chain molecules that are more useful. Cracking is an example of a thermal decomposition reaction
explain steam cracking
Vapourised heavy hydrocarbons are combined with steam in a high temperature environment.
Alkanes and Alkenes are produced by this reaction.
E.g. decane → octane + ethene
explain Catalytic cracking
Vapourised heavy hydrocarbons are passed over the top of a heated catalyst.
Alkanes and alkenes are produced by this reaction.
E.g. hexane → butane + ethene
Give 4 examples of Alkene reactions
When a phosphoric acid catalyst is present, alcohols can be formed by reacting Alkenes with steam,
Alkenes unlike Alkanes, will react if mixed with bromine water and shaken this causes the solution to change colour from orange-brown to colourless,
Alkenes can be involved in combustion reactions with oxygen the outcome of these reactions is similar to when other hydrocarbons react with oxygen,
When a nickel catalyst is present, Alkanes can be formed by combining hydrogen with an Alkene
what is the functional group and general formula of alcohol
The functional group of alcohols is a hydroxyl group (-OH),
the general formula is CnH2n+1OH.
what are 4 reactions of alcohols
When alcohols react with a strong oxidising agent a carboxylic acid is produced,
When alcohols react with air (and heat) carbon dioxide and water are produced,
When alcohols and sodium react together hydrogen is produced,
When alcohols are added to water they dissolve to give neutral solutions
describe the process of fermentation
The process of fermentation involves adding yeast to a sugar solution, the resulting reaction gives:
. An aqueous solution of ethanol
. Carbon dioxide
The ideal conditions for the fermentation of sugar using yeast are:
. A temperature of 37°C.
. A solution that is slightly acidic.
. In the absence of oxygen (anaerobic).
what suffix do carboxylic acids end in
anoic
