Organic Chemistry Flashcards
Define Structural Formulae
A formula which shows the arrangement of atoms in the molecule of a compound but does not show all the bonds between them
Define Molecular Formulae
Formula which is the actual number of atoms of each element in a compound
Define Structural Isomers
Compounds that have the same molecular formula but different structural formula
Define the term homologous series
A family of organic compounds that have similar features and chemical properties due to their functional group
Give 3 characteristics of a homologous series
- Same General Formula
- Same functional group
- Similar chemical properties
Functional Group of an Alcohol?
-OH
General Formula for Alkanes?
CnH2n+2
General Formula for Alkenes?
CnH2n
General Formula for Alcohols?
CnH2n+1OH
General Formula for Carboxylic Acids?
CnH2n+1COOH
What are saturated compounds?
Molecules in which all carbon-carbon bonds are single bonds
What are unsaturated compounds
Molecules in which all carbon-carbon bonds are NOT single bonds
Why are alkenes considered unsaturated?
Because they contain one carbon-carbon double bond (C=C)
What happens to the double bond in alkenes during reaction?
They open up, allowing incoming atoms to form another single bond with each carbon atom of the functional group
What type of bonds do saturated compounds have between carbon atoms?
Single Bonds
What is the name of this compound?
CH3CH2CH2CH2OH
Butanol
What is the name of this compound?
CH3CH2CH2CH2CH3
Pentane
Define fractional distillation
Process of separating the different fractions of crude oil based on their boiling points
What happens to the viscosity of a liquid as the number of carbon atoms increases?
The viscosity of the liquid increases
What happens to the volatility of a liquid as the molecular size increases?
The volatility of the liquid decreases
Define the term viscosity
The ease of flow of a liquid
What is the use of refinery gases?
Cooking
What is diesel used for?
Diesel Engine Oil
Give one use of fuel oil
Fueling Ships
What fraction is used as fuel in cars?
Petrol
Which fraction is used for surfacing roads?
Bitumen
Why do fractions condense inside the fractionation tower?
Because their vapours rise and reach a point where the temperature is below their boiling point
Why does the boiling point of a molecule increase as the molecule becomes larger?
Increased force of attraction, more energy is required to overcome them
What is a hydrocarbon
Compound made up of only hydrogen and carbon
Name three fossil fuels
- Coal
- Natural Gas
- Petroleum
Name the alkane that is predominantly present in natural gas
Methane
What type of reaction occurs between alkanes and halogens
Substitution reaction
State the equation for methane reacting with bromine in the presence of UV light
CH4 + Br2 → CH3Br + HBr
State the equation for methane reacting with chlorine in the presence of UV light
CH4 + Cl2 → CH3Cl + HCl
What condition is required for alkanes to react with halogens?
The condition required for the reaction between alkanes and halogens is ultraviolet radiation / UV light
State three reactions that alkanes can undergo
- Combustion
- Cracking
- Substitution reactions with halogens
Write the balanced equation for the combustion of methane
CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (l)
What is the characteristic feature in the structure of alkenes?
All alkenes contain a double carbon bond, which is shown as two lines between two carbon atoms (C=C)
What is the functional group in alkenes?
The double carbon bond (C=C) is the functional group in alkenes
Define the term alkene
An alkene is a hydrocarbon compound containing at least one carbon-carbon double bond
Explain the term double bond
A double bond is a covalent bond formed by sharing two pairs of electrons between atoms
Explain what is meant by a unsaturated compound
An unsaturated compound contains double or triple bonds, which can undergo addition reactions
What is catalytic cracking?
Catalytic cracking is a process used to convert longer-chain molecules into hydrocarbons that are shorter-chain
What are the products of catalytic cracking?
The products of catalytic cracking are shorter chain alkanes, alkenes, and hydrogen
What conditions are required for catalytic cracking?
The conditions for catalytic cracking are:
- 600 – 700°C.
- A catalyst of alumina or Silica
How can alkenes be distinguished from alkanes?
Alkenes can be distinguished from alkanes using bromine water.
Alkenes will decolorise bromine water, while alkanes will not.
What colour is bromine water?
Bromine water is a brown / red-brown colored solution
What is the reaction between bromine and propene an example of?
an addition reaction
What is an addition reaction?
An addition reaction is a reaction in which atoms of a simple molecule add across the C=C double bond of an alkene
How many products are formed in an addition reaction?
In an addition reaction, only one product is formed
What happens when bromine is added to an alkene?
When bromine is added to an alkene, the two bromine atoms add across the carbon-carbon double bond to form a saturated compound
What product is formed when alkenes undergo addition reactions with hydrogen?
When alkenes undergo addition reactions with hydrogen, an alkane is formed
What catalyst is required for the reaction between alkenes and hydrogen?
The reaction between alkenes and hydrogen requires a nickel catalyst
What product is formed when alkenes undergo addition reactions with steam?
When alkenes undergo addition reactions with steam, an alcohol is formed
What other name is given to the reaction between alkenes and steam?
The reaction between alkenes and steam is also called a hydration reaction
What catalyst is required for the reaction between alkenes and steam?
The reaction between alkenes and steam requires an acid catalyst
How can ethanol be synthesised industrially?
Ethanol can be synthesised by the hydration of ethene
What are the conditions for the hydration of ethene to produce ethanol?
The conditions required for the hydration of ethene are a temperature of around 300°C, pressure of 60-70 atm, and a concentrated phosphoric acid catalyst
How are ethanol and water separated from the reaction mixture after hydration?
Ethene is separated first due to its much lower boiling point, then ethanol and water are separated by fractional distillation
What is the equation for the hydration of ethene to produce ethanol?
CH2=CH2 + H2O → CH3CH2OH
How is ethanol produced by fermentation?
Ethanol is produced by fermentation through yeast enzymes breaking down sugar or starch in the absence of oxygen to produce ethanol and carbon dioxide:
C6H12O6 → 2CO2 + 2C2H5OH
State the meaning of hydration
A chemical reaction in which a water molecule is added to a compound
Explain what is meant by fermentation
A process in which yeast or bacteria convert carbohydrates into alcohol or acids in the absence of oxygen.
What conditions are required for the fermentation of glucose?
The fermentation of glucose requires:
- A temperature between 25 and 35 °C.
- The absence of oxygen.
- The presence of a yeast catalyst.
Write the equation for the fermentation of glucos
C6H12O6 → 2CO2 + 2C2H5OH
Does fermentation or hydration of ethene require high temperature to produce ethanol?
Hydration of ethene requires high temperature to produce ethanol.
What is a carboxylic acid?
A carboxylic acid is a compound containing the functional group carboxyl, -COOH
Which carboxylic acid is found in vinegar?
Vinegar is an aqueous solution of ethanoic acid and contains about 5% of the acid by volume
What is the molecular formula of ethanoic acid?
CH3COOH
What is the functional group of carboxylic acids?
COOH
What is produced when carboxylic acids react with metals?
When carboxylic acids react with metals, a salt and hydrogen gas are produced
What is produced when carboxylic acids react with carbonates?
When carboxylic acids react with carbonates, a salt, water, and carbon dioxide gas are produced
What is produced when carboxylic acids react with bases?
When carboxylic acids react with bases, a salt and water are produced
How do the names of salts formed by carboxylic acids end?
The names of salts formed by carboxylic acids all end in -anoate
Write the equation for the reaction between ethanoic acid and magnesium.
2CH3COOH + Mg → (CH3COO)2Mg + H2
What type of reaction occurs between potassium hydroxide and propanoic acid?
The reaction between potassium hydroxide and propanoic acid is a neutralisation reaction.
How can ethanoic acid be prepared from ethanol?
Ethanoic acid can be prepared by oxidising ethanol with acidified potassium dichromate solution.
What colour change occurs during the oxidation of ethanol to ethanoic acid?
During the oxidation of ethanol to ethanoic acid, the potassium dichromate solution changes from orange to green.
What is the symbol equation for the oxidation of ethanol to ethanoic acid?
CH3CH2OH + O2 → CH3COOH + H2O
What are the two methods used to make carboxylic acids?
- Oxidation by fermentation.
- Using oxidising agents.
What is produced when ethanol undergoes microbial oxidation?
When ethanol undergoes microbial oxidation, a weak solution of vinegar (ethanoic acid) is produced.
What oxidising agent can be used to produce ethanoic acid?
Potassium manganate(VII) can be used as an oxidising agent to produce ethanoic acid.
What is an esterification reaction?
An esterification reaction is a reaction between an alcohol and a carboxylic acid to form an ester.
What is the functional group of esters?
R-COO-R.
What catalyst is required for an esterification reaction?
An acid catalyst, typically concentrated sulfuric acid, is required for an esterification reaction.
How are esters named?
Esters are named by combining the name of the alcohol (ending in -yl) and the name of the carboxylic acid (ending in -oate)
What is the name of the ester formed from pentanol and butanoic acid?
pentyl butanoate.
What is a polymer?
A polymer is a large molecule of high relative molecular mass made by linking together large numbers of smaller molecules called monomers
What is a monomer?
A monomer is a smaller molecule that links together to form a polymer
What type of bonds connect monomers in a polymer?
Monomers in a polymer are connected via covalent bonds
What is the process of making polymers called?
The process of making polymers is called polymerisation
Describe addition polymerisation
Addition polymerisation is a type of polymerisation in which monomers are added to form a polymer chain without the loss of any molecules
How are condensation polymers formed?
Condensation polymers are formed when two different monomers are linked together with the removal of a small molecule, usually water
What is the key difference between condensation and addition polymers?
In addition polymerisation, only the polymer molecule is formed.
In condensation polymerisation, the polymer molecule and one small molecule (typically water) per linkage are formed
How many functional groups are present in the monomers for condensation polymers?
The monomers have two functional groups present, one on each end.
What happens when an ester linkage is formed in condensation polymerisation?
A small molecule is lost, usually water.
What is a dicarboxylic acid?
A dicarboxylic acid is a carboxylic acid with two -COOH groups, one at each end of the molecule.
What is a diol?
A diol is an alcohol with two -OH groups, one at each end of the molecule.
Why are polymers difficult to dispose of?
Polymers are difficult to dispose of because they are unreactive and chemically inert, so they don’t easily biodegrade.
What is incineration of polymers?
Incineration is the process of burning polymers, which releases a lot of heat energy.
What is the main environmental concern with polymer incineration?
The main environmental concern with polymer incineration is the production of carbon dioxide, which is a greenhouse gas.
What is a disadvantage of disposing of polymers in landfills?
Disposing of polymers in landfills takes up valuable land, as they are non-biodegradable and cannot be broken down by microorganisms.
What is a disadvantage of incinerating polymers like PVC?
Polymers that contain chlorine, such as PVC, release toxic hydrogen chloride gas when burned.
Explain the meaning of the term landfill.
Landfill is a site for the disposal of waste materials by burial.
Which two functional groups are found in amino acids?
Amino acids contain the amine / NH2 and carboxylic acid / COOH functional groups.
Name the type of monomers that make up proteins.
The monomers that make up proteins are amino acids.
