Chemistry Topic 7 - Organic Chemistry Flashcards
What is crude oil?
A mixture of compounds; a fossil fuel of the remains of ancient biomass
Finite resource - cannot be replaced as it is used up
What is a hydrocarbon?
A compound made up exclusively of hydrogen and carbon atoms
What is a homologous series?
Series of compounds with same general formula, same functional groups and similar chemical properties
describe the combustion of hydrocarbons
-exothermic reaction occurring when hydrocarbons are reacted with oxygen
-complete combustion produces carbon dioxide and water
-incomplete combustion produces carbon or carbon monoxide and water
Describe the physical properties of alkanes
-first few in series are gases, then change to liquids, then to solids
-in general, boiling points and viscosity increase as molecules get bigger
-volatility and flammability decrease as molecules get bigger
-poor reactivity
What is cracking?
When large hydrocarbons are thermally broken down into smaller and useful molecules
What type of reaction is cracking?
Thermal decomposition
what are the conditions for cracking?
Reactants heated to vapour, passed over a hot catalyst or heated to vapour, mixed with steam and heated to high temperatures
How are the products of cracking used?
The products of alkanes and alkenes - used as polymers and starting materials from synthesis
What is the test for alkenes?
Add bromine water
Colour change occurs from orange to colourless
Describe the combustion of alkenes
They burn with smoky flames due to incomplete combustion
What is an alcohol?
An organic compound that contains an -OH functional group
State characteristics of methanol, ethanol, propanol and butanol
-dissolve in water to from a neutral solution
-react with sodium to form hydrogen
-burn in oxygen
-react with carboxylate acids in presence of acid catalyst to form esters
Oxidation of the alcohols leads to…?
Carboxylic acids
What are some uses of alcohols?
-fuels
-solvents
-drinks
What are carboxylic acids?
Organic compounds that constrain a COOH functional group
State characteristics of carboxylic acids
-dissolve in water to form an acidic solution
-react with metal carbonates to form carbon dioxide
-react with alcohols with an acid catalyst to produce esters
-react with metals to give off hydrogen gas
What type of acid is carboxylic acid?
It is a weak acid
Explain why carboxylic acids are weak acids?
They are partially dissociated in water, thus the pH of a carboxylic acid in solution is not as low as a solution of a strong acid of the same concerntration
What is an ester and how did it form?
An organic compound containing a -COO- functional group, formed from carboxylic acid and alcohol in the presence of a sulfuric acid catalyst
What is a polymer? How do molecules containing C=C bond form polymers?
A polymer is along chain molecules which is made by lots of smaller molecules joining together
C=C bonds open up and many smaller molecules join together to form a chain. No other products are made
It is called an “addition polymerisation” reaction
What is a repeating unit of a polymer?
It is a smaller structure which, upon numerous translations, yields the structure of the polymer.
In addition polymers: to draw it, take a monomer, change C=C to C-C and show additional single bonds extending away from these carbons.
What is an amino acid?
It is an organic compound that contains both a carboxylic acid functionally (COOH) and an amine functional group
What are carbohydrates?
They are organic molecules made of C,H and O. They are biologically relevant
What is DNA ? Describe its role and structure
DNA Is a material that makes up chromosomes-cell structures that store genetic information
DNA is made up of two polymer chains that are held together in a double helix
Each polymer chain can be made from 4 different monomers - nucleotides
