Organic Chemistry

Question 1

How is crude oil formed? Where is it found? What type of resource is it?

Answer 1

Crude oil is found in rocks, and is a finite resource.
It is formed over millions of years from plankton, which is buried in mud.

Question 2

What is the composition of crude oil?

Answer 2

It is made up of hydrocarbons.

Question 3

What are hydrocarbons? What do scientists call them?

Answer 3

Hydrocarbons are molecules made up of hydrogen and carbon atoms only, they are known as alkanes.

Question 4

What is the general formula for alkanes? What are the first 4 alkanes? (Please provide the molecular formula as well)

Answer 4

General Formula - C(n)H(2n+2)
First 4 alkanes.
1. Methane (CH4)
2. Ethane (C2H6)
3. Propane (C3H8)
4. Butane (C4H10)

Question 5

Why are alkanes saturated molecules?

Answer 5

As the carbon atoms are fully bonded to the hydrogen atoms.

Question 6

What is viscosity? How does viscosity change with the increase in chain length of hydrocarbons?

Answer 6

Viscosity tells us the thickness of a fluid, a high viscosity means the fluid flows slowly.

As the size of the hydrocarbon molecules increase, molecules get more viscous.

Question 7

What is flammability? How does flammability change with the increase in chain length of hydrocarbons?

Answer 7

Flammability tells us how easily a hydrocarbon can combust.

As the size of the hydrocarbon increases, the molecules decrease in flammability.

Question 8

What is boiling point? How does boiling point change with the increase in chain length of hydrocarbons?

Answer 8

Boiling point is the temp required for the liquid to turn into a gas.
The first 4 hydrocarbons are gases at room temperature.
As the size of the hydrocarbon increases, the boiling point also increases.

Question 9

What happens during combustion? What is the word equation for the reaction?

Answer 9

Carbon and hydrogen are oxidised.
Fuel + Oxygen forms Carbon Dioxide + Water.

Question 10

How do we separate hydrocarbons? What is it separated into?

Answer 10

We separate hydrocarbons via fractional distillation, the crude oil is separated into fractions which contain hydrocarbons with a similar number of carbon atoms.

Question 11

How does fractional distillation work? (6)

Answer 11

1) Crude oil is heated at a high temperature.
2) Crude oil boils, hydrocarbon evaporates.
3) Crude oil vapour is fed into the FD column.
4) Hydrocarbon vapour rise up the column.
5) Hydrocarbons condense when they reach their boiling point.
6) Liquid fractions are removed, if not, they continue to travel up the column.

Question 12

Where do longer chained hydrocarbons get removed in fractional distillation? Where does short chained hydrocarbons get removed?

Answer 12

Longer chained hydrocarbons get removed at the bottom of the column. Very short hydrocarbons do not condense, and are removed from the top of the column as gases.

Question 13

What are the uses of fractions? (What are the fuels, what are their uses?)

Answer 13

• Petrol and Diesel are used in cars.
• Kerosene is used in jet fuel.
• Heavy fuel oil is used to power ships.
• Liquid petroleum gas is used for camping stoves.

Some are used in petrochemical industry, as solvents, lubricants, detergents and polymers.

Question 14

What is the purpose of cracking?

Answer 14

It convers longer chained hydrocarbons into shorter chained hydrocarbons.

Question 15

What are the products of cracking?

Answer 15

1. Shorter chained alkanes, plus an alkene.

Question 16

What are the two types of cracking? What are their conditions?

Answer 16

• Catalytic cracking, using a high temperature and a catalyst.
• Steam cracking using a high temperature and steam.

Question 17

What are alkenes used for? What is the bond between the two carbon atoms? Are they less or more reactive than alkanes?

Answer 17

Alkenes are used to make polymers, they are more reactive than alkanes and have a double covalent bond between the two carbon atoms.

Question 18

What is the test for alkenes? What are the result?

Answer 18

Test for alkenes using bromine water,
1. Shake the bromine water.
2. If alkene is present, it turns colourless.

Question 19

What is the one rule for cracking equations?

Answer 19

Ensure the number of carbon and hydrogen atoms are equal on both sides of the reaction.

Question 20

What are the general formula of alkenes? What are the first 4 alkenes? (Please provide the molecular formula.)

Answer 20

The general formula for alkenes are C(n)H(2n)
The first 4 alkenes are
1. Ethene (C2H4)
2. Propene (C3H6)
3. Butene (C4H8)
4. Pentene (C5H10)

Question 21

Why are alkenes unsaturated?

Answer 21

As alkenes have two fewer hydrogen atoms with the same number of carbon atoms (double bond)

Question 22

What is a functional group? What is a homologous series?

Answer 22

A functional group is a part of the molecule that determines how they react, a homologous series is where they all have the same functional group.

Question 23

What is the functional group of the alkenes?

Answer 23

The C=C

Question 24

What can we see when alkenes burn in the air?

Answer 24

Smoky flame.

Question 25

What is hydrogenation? What are the conditions? What is the word equation for the reaction?

Answer 25

Hydrogenation is an alkene reacting with hydrogen. The conditions are 150 degrees and a nickel catalyst. The word equation is, alkene + hydrogen to form an alkane.

Question 26

What is hydration? What is the word equation of the reaction? What are the conditions?

Answer 26

Hydration is alkenes reacting with water. Alkene + Water to form an alcohol (reversible) Conditions are, water must be in the form of steam, temperature of 300 degrees, pressure of 70 atm, and a phosphoric acid as a catalyst.

Question 27

How does hydration cause the yield of the alcohol to increase?

Answer 27

Any unreacted alkene and steam are passed back through the catalyst.

Question 28

What forms when an alkene reacts with chlorine, bromine and iodine?

Answer 28

We get a dichloro(alkane) We get a dibromo(alkane) We get a diode(alkane)

Question 29

What is the functional group of alcohols? What can they be used for?

Answer 29

Functional Group of OH. Used for fuels, solvents an alcoholic drinks.

Question 30

What are the first 4 alcohols? (Provide their molecular formula?)

Answer 30

1. Methanol (CH3OH) 2. Ethanol (C2H5OH) 3. Propanol (C3H7OH) 4. Butanol (C4H9OH)

Question 31

What is the word equation for ethanol being made by fermentation of sugar? What are the conditions?

Answer 31

Glucose forms ethanol + Carbon Dioxide Yeast converts sugar into ethanol. It requires a 30 degree temperature and anaerobic conditions.

Question 32

What are the advantages/disadvantages of ethanol being made by fermentation of sugar?

Answer 32

Advantages 1. Sugar comes from plants, so are renewable. 2. Low temperature so not a lot of energy. Disadvantages 1. Product is an aqueous solution, so distillation required to purify requiring energy.

Question 33

What do we observe when sodium reacts with an alcohol? What is the word equation?

Answer 33

We see bubbles of hydrogen gas being produced. Ethanol + Sodium forms sodium ethoxide + hydrogen. (Sodium Methoxide, propoxide, butoxide)

Question 34

What is the word equation for an alcohol reacting with an oxidising agent? What is an example of a oxidising agent?

Answer 34

Alcohol forms a carboxylic acid + water (when reacting with an oxidising agent, like acidified potassium dichromate) E.g Propanoic Acid!

Question 35

What is the word equation for complete combustion of alcohols in air?

Answer 35

Alcohol + Oxygen form carbon dioxide + water.

Question 36

What are the functional group of carboxylic acid, what are the first 4? (Provide molecular formula)

Answer 36

The functional group is COOH. First 4 Carboxylic Acids are 1. Methanoic Acid (HCOOH) 2. Ethanoic Acid (CH3COOH) 3.. Propanoic Acid (C2H5COOH) 4. Butanoic Acid (C3H7COOH)

Question 37

Why are carboxylic acids weak acids in water?

Answer 37

When placed in water, they ionise but the reaction is reversible, the carboxylic acid ion and hydrogen ion can form the carboxylic acid. They only partially ionise in aqueous solutions so are weak acids. They have a higher PH then strong acids.

Question 38

What is the word equation for a carboxylic acid reacting with a metal carbonate?

Answer 38

Carboxylic Acid + Metal Carbonate forms Metal Ethanoate(replace with correct acid) + Carbon Dioxide + Water

Question 39

What is the word equation for when an alcohol reacts with a carboxylic acid? Is it a reversible reaction? Any conditions required?

Answer 39

Carboxylic Acid + Alcohol forms ester + water, reversible reaction, reaction requires sulfuric acid as a catalyst.

Question 40

What is the name of the ester when Ethanol reacts with ethanoic acid? What are some of the attribute/uses of esters?

Answer 40

Ethyl Ethanoate, sweet smell, used in food.

Question 41

What are the two types of polymers? What are they made up of?

Answer 41

The two types of polymers are addition and condensation polymers, they are formed by joining together monomers.

Question 42

In addition polymers, what are the monomers? What is the difference in bonding between the two?

Answer 42

Alkenes are used, in the monomer there is a C=C bond, but in the polymer their is a single bond.

Question 43

How do we name a polymer from the monomer? How do we show the repeating unit?

Answer 43

Name = poly(monomer) To work out the repeating unit, take any two carbon atoms that are next to each other, add brackets and a 'n'

Question 44

How many monomers do we start with in condensation polymerisation? What does each monomer have?

Answer 44

We start with two different monomers, each monomer has the same functional group.

Question 45

What are the two different monomers, what are functional groups.

Answer 45

1. Monomer 1 - is a diol, with two alcohol groups. (HO and OH) 2. Monomer 2 is a hexanedioic acid with two carboxylic acid groups (HOOC, and COOH)

Question 46

What do scientist draw to represent only the functional groups?

Answer 46

Boxes.

Question 47

When we react the two monomers in condensation polymerisation, what does it form?

Answer 47

A polyester and water.

Question 48

How can we write the repeating unit in condensation polymerisation?

Answer 48

Pick any two adjacent monomer units and draw them out, brackets and 'n'

Question 49

What are the two different functional groups amino acids have? What does this mean in polymerisation?

Answer 49

1. Carboxylic Acid Group and Amine Group 2. So they can react to form a condensation polymer and water.

Question 50

Why do we call the polymer a polypeptide?

Answer 50

Because the polymer is made from one type of amino acid.

Question 51

What do we get when we combine different amino acids to the same polymer chain?

Answer 51

Polymer is now called a protein.

Question 52

Where is DNA found? What does it encode?

Answer 52

DNA is found in mostly all living organisms, it encodes the genetic interactions that organisms need to develop and function.

Question 53

How many polymer chains does DNA consist of? What monomers are they made from? How many? What are the 4 letters?

Answer 53

They consist of 2 polymer chains, from monomers called nucleotides, they have 4 different nucleotides, (CATG)

Question 54

What is formed when two polymer chains wrap around each other?

Answer 54

Double helix.