Testing Stuff Flashcards
How do you conduct a flame test?
Dip a wire loop (or soaked wooden splint) into the substance and hold it into a bunsen flame
What colour flame does lithium produce?
Red
What colour flame does sodium produce?
Yellow
What colour flame does potassium produce?
Lilac
What colour flame does calcium produce?
Brick red
What colour flame does barium produce?
Apple green
What happens in sodium hydroxide tests?
When we react sodium hydroxide with a salt, an insoluble metal hydroxide forms as a precipitate.
By identifying the metal hydroxide, this lets us see what metal was in the salt.
What colour is the precipitate when copper (II) is reacted with sodium hydroxide?
Light blue
What colour is the precipitate when iron (II) is reacted with sodium hydroxide?
Light green
What colour is the precipitate when iron (III) is reacted with sodium hydroxide?
Reddish brown
How do you test for carbonates?
Add dilute HCL - produces gas
Bubble gas through limewater - should turn milky (shows it is CO2)
How do you test for ammonia?
Ammonia is an ALKALINE gas so it turns damp red litmus paper blue
How do you test for ammonium salts?
Add sodium hydroxide solution - ammonium salts give off ammonia
How do you test for sulphates?
Add barium chloride solution - White precipitate formed
What are halides?
Ions of group 7 elements e.g. Chloride Bromide Iodide
How do you test for halides?
Add silver nitrate solution
What is produced when chloride ions react with silver nitrate?
White precipitate
What is produced when bromide ions react with silver nitrate?
Cream precipitate
What is produced when iodide ions react with silver nitrate?
Yellow precipitate
How do you test for oxygen?
Relights a glowing splint
How do you test for hydrogen?
Produces a squeaky pop sound when held by lit splint
How do you test for carbon dioxide?
Bubble through limewater - turns milky
How do you test for chlorine gas?
Will bleach damp blue litmus paper
How do you test for alkenes?
Shake with bromine water - alkenes only show colour change from brown/orange to colourless
How do you test for alcohols?
Heat with acidified potassium dichromate solution - alcohols give colour change from ORANGE to GREEN
How does sodium react with water?
It fizzes rapidly, moves around and melts to form a ball on the surface of the water
How does lithium react with water?
Fizzes steadily and floats, becoming smaller until it eventually disappears
Which metals react with water and what do they produce?
Potassium
Sodium
Lithium
Form metal hydroxides and hydrogen gas
How does potassium react with water?
Sparks
Lilac flame
Very quick reaction
