C6.2 - Organic Chemistry Flashcards

1
Q

Hydrocarbon defintion

A

Compounds that contain hydrogen and carbon atoms ONLY.

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2
Q

Alkanes general formula

A

C n, H 2n+2

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3
Q

Saturated vs Unsaturated bonds

A
  • Saturated bonds are SINGLE carbon-carbon covalent bonds
  • Unsaturated bonds are DOUBLE carbon-carbon covalent bonds.
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4
Q

First four prefixes for Hydrocarbons

A
  • Meth (1 carbon atoms)
  • Eth (2 carbon atoms)
  • Prop (3 carbon atoms)
  • But (4 carbon atoms)
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5
Q

What happens during complete combustion? What about incomplete combustion?

A

Complete combustion:
- Carbon & Hydrogen are oxidised, both receiving oxygen.
- They become Carbon Dioxide and Water.

Incomplete combustion:
- Water is still made, but carbon monoxide is made.
- Some carbon atoms are not oxidised at all, released as carbon particles.

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6
Q

Why is incomplete combustion dangerous?

A
  • It releases carbon monoxide.
  • Carbon monoxide is toxic, and causes suffocation.
  • Carbon monoxide displaces oxygen in the blood and deprives vital organs (e.g. brain and heart) of blood.
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7
Q

What is meant by a homologous series?

A

A homologous series is a family of hydrocarbons with similar chemical properties who share the same general formula.

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8
Q

Which (Alkanes/Alkenes) are saturated/Un-saturated?

A
  • Alkanes are saturated (single bonds)
  • Alkenes are unsaturated (contain at least one double bond)
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9
Q

Alkenes general formula

A

C n H 2n

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10
Q

How to draw the displayed formula for an Alkene

A
  • Draw all the carbons in a straight line.
  • Make one of the carbons double bonded.
  • Make sure every carbon has four bonds (add hydrogens)
  • Make sure you don’t add an extra hydrogen to the double bonded carbon.
  • Check back to the formula to make sure it adds up.
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11
Q

What are functional groups?

A

Functional groups are atoms, groups of atoms, or types of bonds in a molecule that are responsible for the characteristic reactions of the substance.

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12
Q

What are addition reactions?

A

When atoms or groups of atoms combine with a molecule to form a larger molecule with no other product.

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13
Q

How to test for an alkene

A
  • Test using orange-brown bromine water.
  • When bromine is added to an alkene, it turns into a colourless compounds.
  • Ethene + Bromine –> Dibromoethane (Addition reaction)
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14
Q

How can we convert an alkene into an alkane?

A

Alkenes can undergo addition reactions with hydrogen in the presence of a nickel catalyst to form alkanes.

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15
Q

Alcohol function group

A

-OH

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16
Q

Alcohol general formula

A

C n H 2n+1 OH

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17
Q

How to draw the displayed formula for an alcohol

A
  • Draw the carbons, then add the hydrogens to the left hand side onward.
  • Add the functional group (-O-H) to the end.
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18
Q

How do alcohols form carboxylic acids?

A
  • By reacting an alcohol with an oxidising agent (oxidising it) we can make a carboxylic acid.
  • Take the alcohol, add the oxidising agent, and add dilute sulfuric acid, and gently warm it.
  • A colour change should be observed.
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19
Q

Functional group of carboxylic acid

A

-COOH
- Acids end in -anoic acid

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20
Q

General formula for carboxylic acid

A

C n H 2n+1 COOH

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21
Q

How do carboxylic acids react (Metals, alkalis, carbonates)? Are they weak/strong acids?

A
  • They are weak acids.
  • They react with METALS to produce salt and hydrogen.
  • They react with ALKALIS and bases to produce salt and water.
  • They react with CARBONATES to produce salt, water and carbon dioxide.
22
Q

Names for the salts formed from carboxylic acid

A
  • They have the ending -oate
  • Ethanoic Acid + Sodium Carbonate –> Sodium Ethanoate + Water + Carbon Dioxide
23
Q

How does crude oil (fossil fuel) form?

A
  • Things that lived millions of years ago die, and they become buried deep into the seabed.
  • They eventually turn into crude oil.
  • This is a long and slow process, so crude oil is non-renewable.
24
Q

What is crude oil made of?

A

A mixture of many different hydrocarbons.

25
Q

How do we separate crude oil?

A
  • Fractional distillation.
26
Q

How does fractional distillation work?

A
  • Hydrocarbons have different boiling points.
  • A fractionating column has different temperature gradients (hottest at bottom).
  • As vapours rise they condense and run off to be collected.
  • Each fraction contains substances with similar boiling points.
27
Q

Temperature gradient in a fractionating column

A

25 degrees (lowest)
350 degrees (highest)

28
Q

Different substances collected from a fractionating column (lowest to highest)

A

LOWEST TEMP
- Bitumen (very top)
- Fuel oil
- Heating oil
- Diesel
- Paraffin
- Petrol
- LPG (very bottom)
HIGHEST TEMP

29
Q

What determines the boiling point of a hydrocarbon?

A

The more carbon atoms, the longer the molecule, so the stronger the intermolecular forces are (so a higher boiling point).

30
Q

What bonds hold atoms in hydrocarbons together?

A
  • Covalent bonds, which are stronger than intermolecular forces.
  • When boiled, the intermolecular forces between molecules are broken, not the covalent bonds.
31
Q

Cracking - What does it do, how does it work

A
  • Cracking converts large hydrocarbon molecules into smaller more useful hydrocarbon molecules.
  • It needs; A catalyst (alumina or silica), High Temperature (600c-700c)
  • Cracking helps to match supply to demand by breaking the covalent bonds between the atoms to make smaller hydrocarbons.
  • E.g. Octane –> Hexane + Ethene
32
Q

Why are large hydrocarbons less useful? Why is cracking so important?

A
  • They do not flow easily and are hard to ignite (low flammability).
  • 90 percent of crude oil is used to produce fuels (e.g. petrol and diesel), so it allows us to match supply to demand.
33
Q

Plastic is a….

A

Polymer

34
Q

Types of polymers

A
  • Addition polymers
  • Biological polymers
  • Condensation polymers
35
Q

How to make addition polymers

A
  • Addition polymers undergo an addition reaction when they join together. They can do this as they contain a C=C bond.
  • The monomers are alkenes.
  • To make these, you need high pressure and a catalyst.
36
Q

How to find the name of a polymer

A

INPUT monomer name
OUTPUT poly + monomer name

37
Q

How to draw the addition polymer of a monomer

A
  • Redraw the monomer BUT:
  • Change the double bond between the carbons to a single bond.
  • Draw square brackets around them.
  • Draw bonds sticking out of the sides of the brackets like arms.
  • Put the letter ‘n’ in the bottom right.
38
Q

How many amino acids are there that naturally occur in the body?

A

20

39
Q

What is a condensation reaction?

A
  • Two molecules react together to form one larger molecule, and one smaller molecule, which is often water.
  • They don’t require a catalyst, and work at room temp/pressure.
  • The monomers for condensation polymers need two functional groups.
  • Carboxylic acid + Alcohol –> Ester (Salt) + Water
40
Q

Two functional groups of amino acids

A
  • Amino group - NH2
  • Carboxyl group - COOH

The monomers are joined by an amide group. -CONH-

41
Q

What is polyester? What is it made up of? What does it make when it joins together? What are its uses?

A
  • It is an artificial condensation polymer.
  • Made from carboxylic acid with 2 carboxyl groups.
  • An alcohol with two hydroxyl groups.
  • When they join together, they form many ester groups (hence the name).
  • Uses include clothing/drink bottles.
42
Q

What is polyamide?

A
  • It is an artificial condensation polymer.
  • Made from carboxylic acid with 2 carboxyl groups.
  • Amine with two amino groups.
  • They form many amide groups when formed (hence the name).
  • They form nylon (an example).
43
Q

What does a fuel cell do?

A
  • A fuel cell produces electricity through a chemical reaction between a fuel and oxygen but without combustion occurring.
44
Q

Pros of fuel cells

A
  • They only require oxygen and hydrogen, which are abundant and easy to source.
  • They don’t produce any waste (e.g. carbon dioxide or other pollutants)
  • Fuel cells are relatively simple devices, so they last longer than batteries do, and they’re less pollution to dispose of.
45
Q

Downside of fuel cells

A
  • Hydrogen is a gas, so it takes up much more volume to store than fossil fuels/batteries.
  • They are explosive when mixed with air, so storing it is difficult.
  • Making the hydrogen fuel in the first place requires energy, which often comes from fossil fuels.
46
Q

Describe how fuel cells work.

A
  • Hydrogen reacts with oxygen in an exothermic reaction to produce water vapour.
  • Hydrogen molecules lose electrons and become hydrogen ions.
  • Hydrogen ions combine with oxygen at the other side to form water vapour.
47
Q

How does a chemical cell work?

A
  • Exothermic reactions in the cell develop a potential difference/voltage between the two ends.
  • When the cell is connected to an electrical circuit, this potential difference drives a current, which flows through the cell and the components of the circuit.
  • This continues until one of the reactants is used up, so a potential difference can no longer be produced.
48
Q

What is a ‘diol’?

A

An alcohol with two functional groups (double OH)

49
Q

What is ‘hydroxyl’?

A

Hydroxyl is alcohol functional group -OH

50
Q

What is ‘carboxyl’?

A

Carboxyl is carboxylic acid functional group -COOH