7 Organic Seperate 1 Flashcards
What are alkenes
A different type of hydrocarbon which is more reactive than an alkane
What are alkenes used for?
As a starting material to make more useful chemicals
How do you test for an alkene?
React it with bromine water
What is the colour change when an alkene reacts with bromine water?
Turns from orange to colourless
What is an alkene?
A hydrocarbon with a double bond
What is the general formula for alkenes?
CnH2n
What does unsaturated means?
Contains double bonds (which could become C-H bonds)
What are the first four alkenes?
Ethene, propene, butene, pentene
What are the four reactions of alkenes?
Combustion, with water, with hydrogen and with halogens
How is the combustion of alkenes different to combustion of alkanes?
Alkenes usually react by incomplete combustion so burn with smoky flames
Why are the reactions of alkenes with hydrogen, water and halogens known as “addition” reactions?
Because new atoms are being added to the molecule by breaking the double bond
What is the product from the reaction of an alkene with hydrogen?
An alkane
What conditions are necessary in the reaction of alkenes with hydrogen?
60oC, Nickel catalyst
What is the product from the reaction of an alkene with a halogen?
An alkane with two halogen atoms where the double bond used to be
What is the product from the reaction of an alkene with steam?
An alcohol
What conditions are necessary for the reaction of alkenes with steam?
High temperature, high pressure, catalyst
What functional group do all alcohols have?
OH
Name and draw the first four alcohols
Methanol, ethanol, propanol, butanol (ethanol pictured)
What happens when an alcohol reacts with sodium?
It forms a sodium salt (e.g. sodium ethoxide from ethanol) and releases hydrogen gas.
What are the products of a combustion reaction involving an alcohol and oxygen?
Carbon dioxide and water
Write a symbol equation for the reaction of methanol/ethanol/propanol/butanol with oxygen
E.g CH3CH2OH + 5O2 gives 2CO2 + 3H2O
Do alcohols dissolve in water?
Yes, they form neutral solutions
How do alcohols react with oxidizing agents?
They turn into carboxylic acids
What are the main uses of alcohols?
Solvents, ethanol used as drinking alcohol and a biofuel
What is fermentation?
The process of turning glucose (a natural sugar) into ethanol
What is required for natural fermentation?
Yeast
What functional groups do all carboxylic acids have?
COOH
Name and draw the first four carboxylic acids
Methanoic acid, ethanoic acid, propanoic acid, butanoic acid (image is ethanoic acid)
Why are carboxylic acids weak acids?
Not all their molecules ionise when in water
What is the product of a reaction between an alcohol and a carboxylic acid?
An ester
