Topic 9 - Separate Chemistry 2 Flashcards
How do you identify metal ions?
Flame test. Burn the compound and see what colour of fame is produced.
How do you test to see if metal ions are present?
Add a few drops of sodium hydroxide to a solution of the mystery compound. If a hydroxide precipitate forms you know metal ions are present and using the colour of the compound you can find out which metal is present.
How do you test for halide ions?
Add dilute nitric acid then silver nitrate solution to a solution of the mystery compound.
What colour of precipitate forms when testing for chlorine ions?
White
What colour of precipitate forms when testing for bromide ions?
Cream
What colour of precipitate forms when testing for iodine ions?
Yellow
How do you test for carbonate ions?
Add dilute acid to the solution. If a gas is produced, do the test for carbon dioxide. If carbon dioxide has been produced then carbonate ions are present.
How do you test for sulphate ions?
First add dilute hydrochloric acid to the solution. Then add barium chloride. If a white precipitate forms than sulphate ions are present.
What ion when burnt gives off a red flame?
Lithium
What ion when burnt gives off a yellow flame?
Sodium
What ion when burnt gives off a lilac flame?
Potassium
What ion when burnt gives off an orange-red flame?
Calcium
What ion when burnt gives off a blue-green flame?
Copper
What colour precipitate does aluminium solution form when sodium hydroxide is added?
White at first, then colourless
What colour precipitate does calcium solution form when sodium hydroxide is added?
White
What colour precipitate does copper solution form when sodium hydroxide is added?
Blue
What colour precipitate does Iron(II) solution form when sodium hydroxide is added?
Green
What colour precipitate does Iron(III) solution form when sodium hydroxide is added?
Brown
What happens when you add sodium hydroxide to ammonium ions?
Ammonia gas is produced
How do you test for ammonia gas?
By holding a piece of red litmus paper to the gas, if ammonia is present the gas will turn blue.
What is a homologous series?
A group of chemicals with the same general formula and similar chemical properties
To form a condensation polymer, what does each monomer need to have?
At least two functional groups, one at each end of the molecule.
When a carboxylic acid group reacts with an alcohol group?
An ester link is formed
What happens when an ester link is formed?
A molecule of water is lost
Name three naturally occurring polymers?
DNA
Amino acid
Carbohydrate
NOTE: you need to know how to draw repeating units of a polymer
CGP guide page 99
NOTE: I’m pretty sure you need to be able to draw condensation polymers
CGP guide page 100
What is the functional group of alcohols?
-OH
What is the functional group of carboxylic acids?
-COOH
Name the first four carboxylic acids
Methanoic acid
Ethanoic acid
Propanic acid
Butanoic acid
Name two conditions for the fermentation of alcohol
Temperature between 30-40°C
Anaerobic conditions
What happens during the fermentation of ethanol when the concentration of ethanol gets above 20%?
The yeast dies, stopping the reaction.
How do you make a concentration of ethanol above 20%?
Use fractional distillation. Ethanol has a lower boiling point than water. The ethanol will evaporate, leaving the water. When the ethanol condenses the concentrated ethanol can be collected.
How do you test for an alkene?
Add bromine water to the solution and shake. The solution will go colourless if an alkene is present.
