Analysis Flashcards
How do you test for oxygen?
Glowing splint relights.
How do you test for carbon dioxide?
Turns limewater cloudy.
How do you test for hydrogen?
Lit splint gives a squeaky pop.
What colour flame does lithium give?
Red
What colour flame does sodium give?
Yellow
What colour flame does potassium give?
Lilac
What colour flame does copper give?
Blue-green
What colour precipitate does silver nitrate make with chloride ions?
White
What colour precipitate shows copper(II) ions are present?
Blue
What colour precipitate shows iron(III) ions are present?
Brown
What must a substance contain to conduct electricity?
Free-moving charged particles (ions or electrons)
When do ionic compounds conduct?
When molten or dissolved
Do covalent compounds conduct electricity?
No — they don’t have charged particles
What device is used to test conductivity?
Ammeter
What type of electrodes are used?
Graphite rods
How do you know a substance conducts?
The ammeter shows current flowing
Where do you read from on a measuring cylinder or burette?
Bottom of the meniscus.
What is a pipette used for?
To measure and transfer a fixed volume of liquid accurately.
What is a standard solution?
A solution with a known concentration.
What flame should a Bunsen burner have for heating?
Blue flame (air hole open).
Why shouldn’t you heat ethanol with a Bunsen burner?
It’s flammable — could catch fire.
What does a hotplate do better than a Bunsen?
Allows temperature to be controlled more accurately.
What gas collection method do you use for hydrogen?
Over water with a measuring cylinder.
What direction does a gas lighter than air move?
Upwards (use downward delivery).
What direction does a gas heavier than air move?
Downwards (use upward delivery).
What is filtration used for?
To separate an insoluble solid from a liquid.
What is crystallisation used for?
To separate a soluble solid from a solution.
What is used to measure temperature accurately?
A thermometer.
Why do you zero a balance before use?
To make sure only the substance is weighed.
What is a cross-section diagram?
A labelled diagram showing how your equipment is set up from the side.
