C8 20 Questions Flashcards
How can you test for hydrogen gas?
Lit splint- Squeaky pop
How can you test for oxygen gas?
Glowing splint- relights
How can you test for carbon dioxide gas?
Limewater- Cloudy
How can you test for chlorine gas?
Litmus paper- Bleaches
How do you calculate the Rf value of a substance?
Distance moved by substance/distance moved by solvent.
What is the mobile phase in chromatography?
Water/solvent
What is the stationary phase in chromatography?
Paper
What is a pure substance?
Single element or compound
What is a formulation?
Mixture to make a useful product.
What colour flame is produced when a sample of barium is used in a flame test?
Green
What type of substances can be analyzed using flame spectroscopy?
Solutions containing metal ions
How can you test if a substance is pure?
Specific melting/boiling point.
Give four advantages of instrumental methods of analysis
Very fast, very sensitive, accurate, can be used on small samples
What is a precipitate?
A solid formed when two solutions are mixed.
What colour is a copper(II)hydroxide precipitate?
Blue
ow can a sulfate be identified?
Add dilute hydrochloric acid and barium chloride solution; look for a white precipitate of barium sulfate
In chromatography, why must the line that the substances are placed on, be drawn in pencil?
Pencil will not dissolve in the solvent.
What colour is a precipitate of silver bromide?
Cream
In chromatography what does the Rf value depend on?
How soluble the solute is in the solvent.
In chromatography why must the solvent height be lower than the pencil line?
So that the substances do not dissolve into the solvent off the paper
