C4.2 mindmap ~ identifying products of chemical reactions
- Created by: shiningswan
- Created on: 09-04-19 11:14
View mindmap
- Chemistry - C4.2 ~ identifying products of chemical reactions
- Detecting cations
- Flame test: Clean loop and dip it into test powder. Hold in roaring blue flame for 10 secs. Record flame colour.
- Li+ = red
- Na+ = yellow
- K+ = lilac
- Ca+ = orange/red
- Cu^2+ = turquoise
- Hydroxide precipitate test: Put metal ion solution in a test tube and add sodium hydroxide solution. Note the precipitate colour formed.
- Fe^2+ = green
- Fe^3+ = orange/brown
- Cu^2+ = blue
- Ca^2+ = white
- Tell apart as Zn^2+ precipitate will dissolve in excess sodium hydroxide
- Zn^2+ = white
- Tell apart as Zn^2+ precipitate will dissolve in excess sodium hydroxide
- Zn^2+ = white
- Flame test: Clean loop and dip it into test powder. Hold in roaring blue flame for 10 secs. Record flame colour.
- Detecting anions
- Testing for halide ions: Add a few drops of dilute nitric acid and a few drops of silver nitrate solution. Record colour of precipitate.
- Cl- = white
- Br- = cream
- I- = yellow
- Testing for sulfate ions: Add a few drops of dilute HCl acid and a few drops of barium chloride solution.
- If sulfate ions present, white precipitate formed
- Testing for carbonate ions: Add a few drops of dilute HCl acid and look for bubbles. Bubble gas through limewater.
- If limewater turns cloudy from CO2 produced, carbonate ions were present
- Testing for halide ions: Add a few drops of dilute nitric acid and a few drops of silver nitrate solution. Record colour of precipitate.
- Gas tests
- Hydrogen: lighted splint pops
- Oxygen: glowing splint relights
- Chlorine: damp blue litmus paper turns red then white
- Carbon dioxide: limewater turns cloudy
- Instrumental methods of analysis
- Interpreting a gas chromatogram
- Each peak represents a substance in the mixture
- Area under each peak shows amount
- Interpreting a mass spectrometer
- Can measure the masses of atoms/ molecules and is used to analyse isotope amounts and molecule structure.
- Sample molecules ionised by machine to form molecular ions
- May break up to form fragments which the machine can separate and detect.
- Sample molecules ionised by machine to form molecular ions
- each peak represents a molecule fragment
- Far right peak represents molecular ion
- Mass to charge ratio of this = Mr of the molecule
- Can measure the masses of atoms/ molecules and is used to analyse isotope amounts and molecule structure.
- Advantages
- sensitive - can detect small amounts
- Very accurate
- Work quickly and can run all the time
- Interpreting a gas chromatogram
- Detecting cations
Comments
No comments have yet been made