C15 - Organic Reactions (PAPER 2) Flashcards
What is a homologous series
a group of compounds with the same functional group
What is a functional group
a group of atoms that determines the properties of a compound
What are alkenes (homologous series)
a homologous series with a double Carbon-carbon bond (C=C)
What is the general formula for alkenes
C(n)H(2n)
How are alkenes formed
through cracking of alkanes
What are the two main uses of alkenes
- formation of polymers
- a chemical feedstock
What happens in the combustion reactions of an alkene, which is more likely
- How does it compare to that of alkanes
- complete combustion produces carbon dioxide and water
- incomplete combustion produces a smoky yellow flame, carbon monoxide / carbon and water
- incomplete combustion is more likely than complete combustion for alkenes
- produces less energy per mole than alkanes
Are alkenes saturated or unsaturated
- Why
unsaturated
- because they have double bonds, so atoms can be added to the molecule by breaking the double bond
What is the product of the reaction between halogens and alkenes
- what is the name of the product when propene and bromine
halogenation
- dibromo propane
What is the product of the reaction of an alkene and hydrogen
- what is the name of the process
alkane
- hydrogenation
What is formed when an alkene reacts with steam
- under what conditions must this be done
an alcohol
- high temperature, high pressure and in the presence of a catalyst (phosphoric acid)
What are alcohols
a homologous series with an -OH group
How are alcohols produced
- What are the formulas
glucose –> ethanol + carbon dioxide
C6 H12 O6 —> 2 C2 H5OH
(fermentation)
alkene + steam —-> alcohol
(alkenes and steam)
What conditions are required to produce alcohols by fermenting
sugar solution with yeast mixed in, warm, sealed vessel
What are the first four alcohols
methanol, ethanol, propanol, butanol
What are 3 uses of alcohols
- ethanol is used in alcoholic drinks
- solvents (as they are easy soluble) (miscible)
- perfumes, aftershaves and mouthwashes
What happens in the combustion of alcohols
short alcohols combust easily with a blue flame, produces carbon dioxide and water
What are the products of the reaction between sodium and alcohol
- what happens when this is added to water
hydrogen and an alkoxide
- a strongly alkaline solution is produced
What organic product is formed through the oxidation of alcohols
- what compounds do the alcohols react with
carboxylic acids
- oxidising agents
Name an oxidising agent
acidified potassium dichromate
What are carboxylic acids
a homologous series with a -COOH group
How are carboxylic acids formed
oxidisation of alcohols
What is a use of ethanoic acid
used in vinegar
What are the first four carboxylic acids called
methanoic acid, ethanoic acid, propanoic acid, butanoic acid
What do carboxylic acids form when reacted with a metal carbonate
salt, carbon dioxide and water
What is formed when a carboxylic acid reacts with an alcohol
- what is required for this reaction
water and esters
- sulfuric acid as a catalyst (usually concentrated)
What is the product between methanol and ethanoic acid
methyl ethanoate
What happens when carboxylic acids are added water
the carboxylic acids become partially ionised to form weakly acidic solutions - they are weak acids
