4.2.1 Alcohols My Own Flashcards

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What functional groups do alcohols have?

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1

What functional groups do alcohols have?

Hydroxyl(OH) functional group

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2

Alcohols with one OH bond general formula

CnH2n+1OH

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3

Structure and bonding of Oxygen in alcohol say shape and why

2 bonding pairs and 2 lone pairs so has a non-linear shape so 104.5 degrees

4 electron regions around the O atom

2 bonding regions and 2 lone pairs so unequal repulsion reduces from 109.5 goes down by 5 degrees to 104.5 degrees bond angle

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4

How do you name alcohols if it is the priority functional group and how do you name it when it is not a priority functional group

Use suffix ol and if more than 3 carbon atoms say the number in-between using smallest number if not the highest priority functional group we use hydroxy prefix

<p>Use suffix ol and if more than 3 carbon atoms say the number in-between using smallest number if not the highest priority functional group we use hydroxy prefix</p>
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5
<p>What is the difference between alcohols and alkenes boiling points when the carbon chain is small and why?</p>

What is the difference between alcohols and alkenes boiling points when the carbon chain is small and why?

Alcohols can form the strongest intermolecular force in hydrogen bonding between OH groups so they have a higher boiling point as more energy is required to overcome the intermolecular forces

Also have IDDI as alkanes only have IDDI which are weak and don't require a lot of energy to overcome the intermolecular forces so large difference between alcohols and alkenes

<p>Alcohols can form the strongest intermolecular force in<strong> hydrogen bonding between OH groups</strong> so they have a <strong>higher </strong>boiling point as more energy is required to overcome the intermolecular forces </p><p> Also have IDDI as alkanes only have IDDI which are weak and don't require a lot of energy to overcome the intermolecular forces so large difference between alcohols and alkenes</p>
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6

What is the difference between alcohols and alkenes boiling point when the carbon chain is large

The more carbon atoms the difference in boiling points decrease as in alcohols the contribution of IDDI increases and hydrogen bonding is reduced so the boiling point of longer chain alcohols are only slightly higher

As carbon-carbon chain gets longer Electrons increase so IDDI strength increases which narrow the gap in boiling point as they have more significance but less influence of hydrogen bonds

<p>The more carbon atoms the difference in boiling points decrease as in alcohols the contribution of IDDI increases and hydrogen bonding is reduced so the boiling point of longer chain alcohols are only slightly higher </p><p>As carbon-carbon chain gets longer Electrons increase so IDDI strength increases which narrow the gap in boiling point as they have more significance but less influence of hydrogen bonds </p>
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7

What is alcohols volatility

The higher the boiling point the lower the volatility so alcohols have lower volatility if have the same carbon atoms so the hydrogen bond makes it less volatile

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8

How does solubility in water of alcohols change as we increase the carbon-carbon chain

As we increase the length of the carbon chain the non-polar carbon chain cannot form hydrogen bonds it is non-polar so a greater part of the molecule is unable to hydrogen bond with water molecules so becomes for insoluble as contribution of OH bond decreases

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9

What is a primary alcohol

The -OH group is attached to a carbon with only one alkyl group

<p>The -OH group is attached to a carbon with only one alkyl group</p>
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10

What is a secondary alcohol

The -OH group is attached to a carbon with two alkyl groups

<p>The -OH group is attached to a carbon with two alkyl groups</p>
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11

What is a tertiary alcohol

The -OH group is attached to a carbon with three alkyl groups

<p>The -OH group is attached to a carbon with three alkyl groups</p>
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12

Can all Alcohols be Oxidized to a Carbonyl?

Primary, Secondary but not tertiary

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13

volatility definition

The tendency to turn into a gas

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14

What is a complete combustion reaction of alcohols

Alcohols burn in an excess of oxygen to form carbon dioxide + water

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15

What does a dehydration reaction do and what is it described as?

Removes a water molecule, forming an alkene forming an alkene it is a elimination reaction H and OH ore being taken out from two adjacent carbons to form water and a double bond forms

<p>Removes a water molecule, forming an alkene forming an alkene it is a <strong>elimination</strong> reaction H and OH ore being taken out from two adjacent carbons to form water and a double bond forms </p>
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16

In an elimination reaction which individual molecules are removed and from where?

The H and OH are removed and double bond forms in between the H and OH happens on one of the two adjacent carbons on either side to the OH group

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17
<p>Reagents and Conditions for dehydration of alcohols</p>

Reagents and Conditions for dehydration of alcohols

Reagents: Concentrated phosphoric acid(H3PO4) catalyst

Conditions: warm Heated under reflux forms an alkene

<p>Reagents: Concentrated  phosphoric <strong>acid(H3PO4) catalyst</strong></p><p>Conditions: warm Heated under <strong>reflux</strong> forms an alkene</p>
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18

What do substitution reactions react with to form

Alcohols can react with hydrogen halides and the alcohol switches with halide + products to form haloalkanes

<p>Alcohols can react with <strong>hydrogen halides</strong> and the alcohol switches with halide + products to form haloalkanes</p>
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19

Reagents and conditions for substitution of alcohols reaction

An alcohol is heated, under reflux, in the presence of sodium halide and dilute sulfuric acid, hydrogen halide forms in situ.

H2SO4 +NaBr → HBr +NaHSO4

NaCl(s)+H2SO4(aq) →Na2HSO4(aq) + HCl(aq)

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20

What does in situ mean and what is the equation of it

in its original place NaCl + H2SO4-> NaSO4 + HCl

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21

Oxidation of primary and secondary alcohols reagents

acidified potassium dichromate/ K2C2O7 in dilute sulfuric acid, H2SO4

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22

Primary alcohols to Aldehyde conditions

Distillation

<p>Distillation</p>
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23

What happens to acidified potassium dichromate if oxidation occurs

The oxidising reagent a colour change from orange to green will occur in this reaction because dichromate(Cr2O7 2-) is being reduced to chromium (Cr3+). (OMG) orange makes green

<p>The oxidising reagent a colour change from orange to green will occur in this reaction because dichromate(Cr2O7 2-) is being reduced to chromium (Cr3+). (OMG) <strong>orange</strong> makes<strong> green</strong></p>
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24

Primary alcohols to Carboxylic acid conditions

If the oxidising agent is used in excess and heating under Reflux

<p>If the oxidising agent is used in excess and heating under Reflux</p>
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<p>Secondary alcohols to Ketones conditions</p>

Secondary alcohols to Ketones conditions

Heat under Reflux

<p>Heat under Reflux</p>
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26

RCH2OH -> [O] forms

RCHO + H2O

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27

RCHO + [O]

RCOOH

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28

How many times does primary alcohols get oxidised to carboxylic acid

2 oxidations

<p>2 oxidations</p>
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29

How many times does primary alcohols get oxidised to aldehyde

1 oxidation

<p>1 oxidation</p>
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30

How do we balance oxidation if we need more oxygens

We balance it by adding H2O

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31

RCHOHR + [O] forms

RCOR + H2O

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32

What conditions do secondary alcohols oxidation have and what is formed

reflux and a ketone is formed + H2O

<p>reflux and a ketone is formed + H2O</p>
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33

Can tertiary alcohols be oxidized and what happens to acidified potassium dichromate

No and solution stays orange

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34

What properties do alcohols have?

Flammable and volatile

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35

Why is there an increase in the boiling point of the alcohols as chain length increases?

Longer chain length more electrons so stronger Induced dipole dipole interactions so more energy required to overcome

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36
<p>Are short chained alcohols water soluble </p>

Are short chained alcohols water soluble

They can form hydrogen bonds with water because of OH group which is polar energy released has to overcome intermolecular forces between alcohol molecules

<p>They can form hydrogen bonds with water because of OH group which is polar energy released has to overcome intermolecular forces between alcohol molecules</p>
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37

Why are longer chained alcohols less water soluble?

As we increase the length of the carbon chain the non-polar carbon chain cannot form hydrogen bonds it is non-polar  so  a greater part of the molecule is unable to hydrogen bond with water molecules  so energy is not released to overcome the intermolecular forces between alcohol molecules

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38

Can ketones be oxidised further?

No

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39

Products of alcohols under complete combustion

CO2 and H2O

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40

Aldehyde naming

Al suffix and doesn’t need to be numbered as the C=O bond is on the first carbon

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41
<p>What is distillation?</p>

What is distillation?

In general used as separation technique to separate an organic product from its reacting mixture. In order to maximise yield collected, only collect the distillate at the approximate boiling point of the desired aldehyde and not higher.

<p>In general used as separation technique to separate an organic product from its reacting mixture. In order to maximise yield collected, only collect the distillate at the approximate boiling point of the desired aldehyde and not higher.</p>
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42

What is reflux?

Reflux is used when heating organic reaction mixtures for long periods. The condenser prevents organic vapours from escaping by condensing them back to liquids

Never seal the end of the condenser as the build up of gas pressure could cause the apparatus to explode. This is true of any apparatus where volatile liquids are heated including the distillation set up.

Anti-bumping granules are added to the flask in both distillation and reflux to prevent vigorous, uneven boiling by making small bubbles form instead of large bubbles.

<p>Reflux is used when heating organic reaction mixtures for long periods. The condenser prevents organic vapours from escaping by condensing them back to liquids</p><p>Never seal the end of the condenser as the build up of gas pressure could cause the apparatus to explode. This is true of any apparatus where volatile liquids are heated including the distillation set up.</p><p>Anti-bumping granules are added to the flask in both distillation and reflux to prevent vigorous, uneven boiling by making small bubbles form instead of large bubbles.</p>
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43

Ketone naming

Ending is one and when ketones have more than 5 carbons in a chain then it needs a number to show the position of the double bond

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44

Why can’t tertiary alcohols be oxidised further?

This is because there is no hydrogen atom bonded to the carbon with the OH group

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45

CH3CH2OH + 2[O] →

CH3COOH + H2O

<p>CH3COOH + H2O</p>
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