Carboxylic acids (Edexcel IGCSE Chemistry (Modular): Unit 2): Flashcards
Exam code: 4XCH1
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Define carboxylic acid.
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Define carboxylic acid.
A carboxylic acid is an organic compound containing the carboxyl (-COOH) functional group. The general formula is CnH2n+1COOH.
Complete the table of the first four carboxylic acids.
Name
Formula
Methanoic acid
CH3COOH
Propanoic acid
CH3CH2CH2COOH
Complete the table of the first four carboxylic acids.
Name
Formula
Methanoic acid
HCOOH
Ethanoic acid
CH3COOH
Propanoic acid
CH3CH2COOH
Butanoic acid
CH3CH2CH2COOH
How are carboxylic acids named?
Carboxylic acids are named using the pattern alkan + oic acid. For example, the two-carbon acid is called ethanoic acid.
True or False?
Vinegar is a dilute aqueous solution of ethanoic acid.
True.
Vinegar contains about 5% ethanoic acid by volume dissolved in water. Ethanoic acid is a carboxylic acid with the formula CH3COOH.
The carbon atom in the .......... functional group is counted as part of the carbon chain, so CH3CH2CH2COOH has .......... carbon atoms and is called butanoic acid.
The carbon atom in the -COOH functional group is counted as part of the carbon chain, so CH3CH2CH2COOH has four carbon atoms and is called butanoic acid.
What is the carboxyl group?
The carboxyl group is the -COOH functional group found in all carboxylic acids. It consists of a carbonyl (C=O) and a hydroxyl (-OH) group bonded to the same carbon atom.
True or False?
The general formula of a carboxylic acid can be written as RCOOH.
True.
RCOOH is a shorthand for the general formula of a carboxylic acid, where R represents the varying hydrocarbon chain attached to the -COOH group.
What is the formula of ethanoic acid?
The formula of ethanoic acid is CH3COOH. It is the second member of the carboxylic acid series and is found in vinegar.
What two types of substance do carboxylic acids react with?
Carboxylic acids react with metals and carbonates. This behaviour is typical of acids in general.
When a carboxylic acid reacts with a metal, it produces a .......... and .......... gas.
When a carboxylic acid reacts with a metal, it produces a salt and hydrogen gas.
True or False?
Salts formed from carboxylic acids end in the suffix -anoate.
True.
The salts of carboxylic acids all end in -anoate. For example, ethanoic acid forms salts called ethanoates.
When a carboxylic acid reacts with a carbonate, the products are a salt, .......... and .......... gas.
When a carboxylic acid reacts with a carbonate, the products are a salt, water and carbon dioxide gas.
What is the name of the salt formed when ethanoic acid reacts with magnesium?
The salt formed is magnesium ethanoate. This follows the naming rule that salts from carboxylic acids end in -anoate.
True or False?
Butanoic acid reacts with potassium carbonate to form potassium butanoate.
True.
Butanoic acid reacts with potassium carbonate to form potassium butanoate, water and carbon dioxide. This is a typical reaction of a carboxylic acid with a carbonate.
What does the suffix -anoate tell you about a compound?
-anoate tells you the compound is a salt formed from a carboxylic acid. For example, magnesium ethanoate is the salt of ethanoic acid.
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