Organic chemistry Flashcards

1
Q

What is a homologous series?

Give two examples of a homologous series.

A

It is a series of molecules that have a general formula.

The alkanes and alkenes.

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2
Q

Alcohols contain which functional group?

If one hydrogen molecule from each alkane is replaced with this functional group, what do we get?

A

-O-H

A homologous series of alcohols

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3
Q

What is the structural formula of…
Methanol?
Ethanol?
Propanol?

A

Methanol - CH3OH
Ethanol - CH3CH2OH
Propanol - CH3CH2CH2OH

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4
Q

Carboxylic acids contain which functional group?

A

-COOH

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5
Q

What is the structural formula of…
Methanoic acid?
Ethanoic acid?
Propanoic acid?

A

Methanoic acid - HCOOH
Ethanoic acid - CH3OOH
Propanoic acid - CH3CH2COOH

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6
Q

Esters contain which functional group?

An ester is formed if the H atom in the -COOH- group of a carboxylic acid is replaced by what?

A

-COO-

A hydrocarbon group

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7
Q

What is the structural formula of ethyl ethanoate?

A

CH3COOCH2CH3

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8
Q

When an alcohol burns completely in air what are the products?

A

Carbon dioxide and water

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9
Q

Give four uses of alcohols.

A

1) Alcohols with smaller molecules mix well with water and produce neutral solutions.
2) Solvents - many organic substance dissolve in alcohols.
3) Alcoholic beverages - ethanol is the main alcohol in wine, beer an other alcoholic drinks.
4) Used a s fuels in spirit burners or combustion engines, the can be mixed with petrol.

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10
Q

When sodium reacts with an alcohol, what gas is produced?

How does this reaction compare to the reaction between sodium and water?

A

Hydrogen

It is lees vigorous

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11
Q

How can alcohols be oxidised and what is the product of this reaction?

A

They can be oxidised by oxidising agents such as potassium dichromate to produce carboxylic acids and ethanol can be oxidised by some microbes in air to produce ethanoic acid.

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12
Q

What will ethanoic acid do to alcoholic drinks and in which substance is it the main acid?

A

It will turn alcoholic drinks sour

Vinegar

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13
Q

What happens when a carboxylic acid is added to water?

A

They dissolve in water to produce solutions with a pH of less than 7.

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14
Q

What are the products when carboxylic acids are reacted with alcohols and what substance must be used as a catalyst in this reaction?

A

The products are an ester and water.

The reaction is conducted in the presence of an acid catalyst.

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15
Q

What term is used to describe esters, what makes them appropriate to use as flavourings and in perfumes.

A

Volatile compounds

They have distinctive smells

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16
Q

Why are carboxylic acids weak acids?

In aqueous solutions of equal concentration how are weak acids different from strong acids?

A

When carboxylic acids dissolve in water the do not ionise completely and some of the carboxylic acid molecules remain as molecules in the solution.
Acids that do not ionise completely are known as weak acids.

Weak acids have a higher pH and react more slowly than strong acids.

17
Q

Give advantages and disadvantages of the use of organic molecules?

A

Advantages:
1) Carboxylic acids and esters are important organic chemicals that have many uses, in foods, in drinks, as solvents and as fuels for the benefit of society.
2) Biofuels offer an alternative to fossil fuels and may help to solve problems with diminishing resources and climate change.
Disadvantages
1) Alcoholic drinks and solvents can be abused which can lead to health and social problems.
2) Some of the crops used in the production of biofuels require the use of agricultural land which could be used to grow food.