Chemical analysis Flashcards
What is a pure substance
A substance with only one type of atoms or molecules, not mixed with anything else
How can you tell if a substance is pure
If it only melts or boils at one specific temperature
Then compare the temperature it boils at to a data book
What effect do impurities have on melting range
It makes the melting range bigger i.e makes boiling points higher and melting point lower
What is a formulation
A mixture that is designed for a specific purpose.
The components in the formulation are at a specific ratio to ensure the formulation can do its purpose
What is 2 examples of a formulation
Paint and resin
What is chromotography
A method to seperate substances in a mixture
What is the mobile phase in chromotography
A state in which molecules can move- either liquid or gas
What is the stationary phase
A state in which molecules cannot move- A solid or thick liquid
How do you calculate Rf
Distance travelled by Substance /
Distance travelled by Solvent
It is always less than 1
How do you test for chlorine
Damp blue litmus paper will turn white
How do you test for Oxygen
It will re- light a glowing splint
How do you test for carbon dioxide
Limewater will turn cloudy
How do you test for hydrogen
Use a lit splint and a tube of hydrogen
The hydrogen will make the lit splint make a squeaky pop sound
How can you test for Carbonates
Add some dilute acid to the sample
Connect the tube to a vile of limewater
If the limewater goes cloudy then there was carbonates presentas CO2 was released
How can you test for sulfates
Drop some dilute HCl (to purify)
Drop some barium chloride solution
The barium chloride should react with the sulfate and a white precipitate of barium sulfate should form.
How can you test for halides
Add Nitric acid and silver nitrate to the mytery solution
Chlorine gives a white precipitate
Bromine gives a crean precipitate
Iodine gives a yellow precipitate
What is a flame test
When you put a piece of metal in a flame and it comes out as a different colour and you can work out what metal it is
Give the results for all the flame tests
Li- Crimson
Ca- Orange
Na - Yellow
Cu- Green
K- Lilac
What is the method of doing a flame test
Dip a platinum loop into Hcl then hold it ontop of a bunsen burner until there is no coloured flame anymore.
Dip the loop into the sample and then put it into the flame to see the colour change
What substance do you use for finding metal hydroxide precipitates
Sodium hydroxide
What is the colour of calcium precipitate when mixed with sodium hydroxide
White
What is the colour of Copper precipitate when mixed with sodium hydroxide
Blue
What is the colour of Iron II precipitate when mixed with sodium hydroxide
Green
What is the colour of Iron III precipitate when mixed with sodium hydroxide
Brown
