Carboxylic acids & derivatives Flashcards
Which carbon is carbon 1 when naming a carboxylic acid
The carbon with the carboxyl group
What is the test for for carboxylic acids. State the reagent and observation
Write the full and ionic equation for the test for ethanoic acid
Reagent: Na2CO3
Observation: Effervescence due to CO2
2CH3COOH + Na2CO3 –> 2CH3COONa + CO2 + H2O
2H+ + CO32- —> CO2 + H2O
What is the general equation when a carboxylic acid reacts with a carbonate
carboxylic acid + carbonate –> Salt + water + carbon dioxide
What type of acid are carboxylic acids
Weak acids
What do carboxylic acids dissociate into
H+ and carboxylate ion
Write the equation for the reaction between ethanoic acid and sodium carbonate
What is the general equation for the reaction between a carboxylic acid and an alcohol
carboxylic acid + alcohol <—> Ester + water
What are the conditions for the reaction between a carboxylic acid and an alcohol to form an ester
Concentrated H2SO4 catalyst
Warm conditions
How do we name an ester
The first part is named from the alcohol used, and the second is named from the carboxylic acid
How do we name an ester with a methyl group
We number the carbons with carbon 1 being the carbon with the =O
Give 4 uses of esters
Perfumes
Food flavourings
Solvents
Plasticisers
Why are esters good solvents
They are polar so other polar solvents will dissolve well in them
Why can esters be used in making glues
They have a low boiling point and evaporate easily
What is the general equation for the hydrolysis of an ester in acidic conditions
Ester + water <—> carboxylic acid + alcohol
What is the general equation for the hydrolysis of an ester in alkaline conditions
Ester + sodium hydroxide —-> carboxylate salt + alcohol
What are the conditions for the hydrolysis of an ester in acidic conditions
Dilute H2SO4 catalyst
Hot conditions (reflux)
What are the conditions for the hydrolysis of an ester in alkaline conditions
Aqueous NaOH
Hot conditions (reflux)
Why is the hydrolysis of an ester in alkaline conditions to form a carboxylic acid preferred over acidic conditions and why may it not be preferred
2 step reaction so lower yield
Both reactions are not reversible so goes to completion
Which way does equilibrium shift when we add water to the hydrolysis of an ester in acidic conditions
Equilibrium shifts right and so more of the product is produced
How do we turn a carboxylate salt from the hydrolysis of an ester in alkaline conditions into a carboxylic acid
Add dilute HCl
Write the general equation for the reaction between a carboxylate salt and HCl
Carboxylate salt + HCl —> Carboxylic acid + chloride salt
What are the conditions for the reaction between a carboxylate salt and HCl to form a carboxylic acid
Warm carboxylate salt
Dilute HCl
What is propane-1,2,3-triol also known as
Glycerol
What do we get when we react glycerol and fatty acids together
An ester
What is a saturated fatty acid
Long chain carboxylic acid with no double bonds
What is an unsaturated fatty acid
Long chain carboxylic acid with double bonds
Explain why vegetable oils are liquid at room temperature
They have unsaturated carbon chains that aren’t straight and so cant be packed close together, hence they have lower VDW forces, therefore have lower M.P’s and are liquids at room temp
What type of molecule are oils
Ester
What type of molecules are fats
Ester
Explain why animal fats are solid at room temperature
They have saturated hydrocarbon chains that are straight and uniform which means they can be packed close together and have much higher VDW forces. Therefore they have high M.P’s and are solid at room temp