Organic Chemistry

Question 1

Hydrocarbons

Answer 1

Any compound with carbon and hydrogen atoms only

Question 2

Alkanes

Answer 2

Simplest type of hydrocarbons
saturated
A homologous series
General formula is CnH2n+2

Question 3

Saturated

Answer 3

Each carbon atom forms 4 single covalent bonds

Question 4

1st 4 alkanes

Answer 4

Methane
Ethane
Propane
Butane

Question 5

The shorter the carbon chain…

Answer 5

less viscous, more flammable, more volatile - lower boiling points (stored under pressure as liquids)

Question 6

Complete combustion of hydrocarbon in oxygen

Answer 6

hydrogen + oxygen = carbon dioxide and water + energy

(C02 and H20 waste products) - hydrogen and carbon oxidised

Question 7

Why are hydrocarbons used as fuels?

Answer 7

Due to amount of energy released when they combust completely

Question 8

Crude oil

Answer 8

Fossil fuel - formed from remains of mainly planktons as well as plants and animals that died millions of years ago and buried under mud. Over millions of years with high temperature and pressure, remains turn into crude oil and drilled from rocks.

Question 9

Fractional Distillation with crude oil

Answer 9

1. Oil is heated until most of it turns into gas and gas enters a fractioning column.
2. In column there’s a temperature gradient (top is cooler + bottom is hotter
3. Longer hydrocarbons have boiling points and are condensed as liquid and drained earlier on near bottom
4. Shorter hydrocarbons have lower boiling points and condense and drain later on near top of column
5. Crude oil mixtures separated into different fractions and each fraction has a mixture of hydrocarbons containing similar n.o of carbon atoms = similar boiling points

Question 10

Disadvantages of crude oil

Answer 10

non-renewable and finite

Question 11

Crude oil Uses

Answer 11

Provides fuel for most modern transports
Polymers
Lubricants
Detergents

Question 12

Why large variety of crude oil uses in products?

Answer 12

Carbon atoms can bond together to from different groups of homologous series + these group contain similar compounds with many common properties

Question 13

Cracking

Answer 13

Long alkane molecules produced from fractional distillation are turned into smaller + more useful ones in cracking

Question 14

Catalytic method of cracking

Answer 14

Thermal decomposition reaction (breaking molecules down by heating them)

1. Heat long chain hydrocarbons to vaporise them
2. vapour passed over hot powdered aluminium oxide catalyst
3. long chain molecules split apart on surface of specks of catalyst

Question 15

Steam cracking

Answer 15

Hydrocarbons vaporised and mixed with steam and heated in high temperature.

Question 16

Alkenes

Answer 16

hydrocarbons with a double bond between 2 of the carbon atoms in chain, which means alkenes have 2 fewer hydrogens compared to alkanes of same n.o carbons =. alkenes are unsaturated (alkenes end with -ene)

Question 17

General Formula for alkenes

Answer 17

CnH2n

Question 18

Combustion of alkenes in large amount of oxygen

Answer 18

complete - Produce only water and carbon dioxide
Shortage of oxygen - water and carbon monoxide (toxic)
Further shortage of oxygen - water and carbon (breathing problems + global warming)
No oxygen - no combustion

Question 19

Physical results of incomplete combustion

Answer 19

Smoky yellow flame + less energy produced

Question 20

Functional group

Answer 20

Group of atoms in a molecule that determines how that molecule typically reacts

Question 21

Functional group of alkenes

Answer 21

C=C - react similarly

Question 22

How do alkenes most react?

Answer 22

Addition reactions - carbon double bond will open to leave a single bond and new atom is added to each carbon

Question 23

Hydrogenation

Answer 23

= saturated alkane

150 degrees Celsius + nickel catalyst

Question 24

Hydration

Answer 24

Alkenes react with team, water is added across double-double bond = alcohol

Question 25

Hydration in alcohol production

Answer 25

After hydration with ethanol, reaction mixture passed through reactor to condenser and as ethanol and water have a higher boiling point than ethane, with condense while unreacted ethane gas is recycled into reactor. Alcohol is purified from mixture with fractional distillation.

Question 26

Halogenation

Answer 26

Addition reactions with halogens = haloalkanes | Molecules formed are saturated with C=C carbons, each carbon bonded to halogen atom

Question 27

Polymers

Answer 27

Long molecules formed when lots of smaller molecules called monomers joined together (polymerisation)

Question 28

Polymers in plastic

Answer 28

Carbon based and monomers are often alkenes

Question 29

Addition polymerisation

Answer 29

Made up of monomers with double covalent bond. Many unsaturated monomer molecules open their double bond to join together to form polymer chain. Product. = polymer - same type and n.o of atoms as monomers formed

Question 30

Naming polymers

Answer 30

Type of monomer in brackets and 'poly' attached infront of it - poly(propene)

Question 31

General formula of alcohol

Answer 31

CnH2n+1OH (-OH group so write like CH30H not like CH40)

Question 32

Naming alcohols

Answer 32

replace 'e' with 'ol'

Question 33

Properties of 1st 4 alcohols

Answer 33

Soluble in water (neutral pH) | React with sodium =- one product is hydrogen

Question 34

Carboxylic acids in Alcohols

Answer 34

Alcohols are oxidised and different alcohols make different carboxylic acids

Question 35

Alcohols as solvent and fuels

Answer 35

(Solvent)Methanol and ethanol used as solvents - they can dissolve most thing water can dissolve +dissolve substances that water can't (Fuel) 1st four used as fuels

Question 36

Fermenation

Answer 36

Ethanol produced form fermentation where enzyme in yeast converts sugars into ethanol and CO2 Happens fastest at 37 degrees Celsius slight acidic solution in anaerobic respiration

Question 37

Word equation for fermentation

Answer 37

sugar - yeast - ethanol + carbon dioxide

Question 38

If low/high pH/temperature...

Answer 38

Denatured / work at slower rate

Question 39

Carboxylic acids

Answer 39

homologous series of compounds with COOH as a functional group

Question 40

Naming carboxylic acids

Answer 40

End in 'anoic acid' and start with normal meth/eth/prop/but

Question 41

Reaction of carboxylic acids with carbonates

Answer 41

React with carbonate to produce salt, water + carbon dioxide

Question 42

Reaction of carboxylic acids with water

Answer 42

Dissolve in water - ionise + release H+ ions = acidic solution. Don't ionise completely - not every acid molecules produces H+ ions - so weak acidic solutions. Higher pH than aqueous solution of strong acids with same concentration

Question 43

Esters

Answer 43

Functional group of COO | Formed from carboxylic acids and alcohols (using a acid catalyst usually)

Question 44

Word equation of esters

Answer 44

Carboxylic acid + alcohol = acid catalyst = ester + water