Chemical Analysis C8 Flashcards
What is a pure substance in chemistry?
something that only contains one compound or element throughout
How can you test for a pure substance?
By checking the boiling and melting point as pure substances have pre determined boiling and melting points
What is a formulation?
Formulations are useful mixtures with a precise purpose made by following a specific formula
What industry are formulations very prominent in?
The pharmaceutical industry so the drug has the right concentration and correct shelf life
Where can you find formulations in everyday life?
Cleaning products, fuel, cosmetics, fertilisers
What is chromatography?
An analytical method used to separate the substances in a mixture. It can then be used to identify substances
What is a mobile phase?
Where the molecules can move. This is always a liquid or gas
What is a stationary phase?
Where the molecules cant move. This can be a solid or very thick liquid
What is the stationary phase in paper chromatography?
The chromatography paper
What is the mobile phase in paper chromatography?
The solvent
What is the RF value meant to represent?
The ratio between the distance travelled by the dissolved substance and the distance travelled by the solvent.
How do you calculate RF value?
by dividing the distance travelled by the dissolved substance and the distance travelled by the substance
What is the test for chlorine?
Chlorine bleaches damp litmus paper, turning it white
What is the test for Oxygen
when you put a glowing splint inside a test tube containing oxygen, the glowing splint will reignite
What is the test for carbon dioxide
Bubbling carbon dioxide through lime water causes the solution to turn cloudy
What is the test for hydrogen?
If you hold a lit splint at the end of test tube containing carbon dioxide, you will get a squeaky pop
How do you test for sulfates with HCL and Barium chloride?
Use a pipette to add drops of dilute HCL followed by drops of BaCl₂ to test tube. If sulfate ions present a white precipitate will form
How to test for halide ions?
add a couple of drops of dilute nitric acid followed by drops of silver nitrate solution.
Chloride: white precipitate (milk)
Bromide: cream precipitate (cream)
iodide: yellow precipitate (butter)
What colours form for certain metal ions in flame test?
Lithium ions - Crimson flame
Sodium ions - Yellow flame
Potassium ions - Lilac flame
Calcium ions - Orange red flame
Copper ions - Green flame
How does flame emission spectroscopy work?
1: When sample is placed in flame, electrons and become excited and heat up
2: When electrons drop back to normal energy level, light is produced from transferred energy
3: this energy is picked up by spectroscope which shows the different wavelengths of certain lights
4: You can then match the wavelengths to a substance
How to test for Carbonates?
By putting a dilute acid in carbonates, carbon dioxide is produced which can be bubbled through limewater which proves that it is carbon dioxide if it turns cloudy
How can we test for the presence of metals in a compound other than in a flame test
By adding Sodium hydroxide to a compound it may form a metal hydroxide, many metal hydroxides are insoluble so it will form a precipitate and you can work out what metal it is by the colour
What colours will metals form when added to Sodium Hydroxide
Calcium - White
Copper - Blue
Iron 2 - Green
Iron 3 - Brown
Aluminum - White at first but then colourless when in excess Sodium Hydroxide
Magnesium - White
