C12 Chemical Analysis Flashcards
What is a pure substance?
A substance containing a single element or single compound
What is a mixture (impure substance)?
A substance containing two or more elements that are physically placed together but not chemicaly combined
What can be said about the melting/boiling point of a pure substance?
They have specfic temeperatures
What can be said about the melting/boiling point of mixtures (impure substances)?
They are over a range of temperatures
What is a formulation?
A useful mixture designed for a specific purpose made in fixed proportions
What are examples of a formulation?
Paints, Drugs, NPK fertilizers
What is the Rf Value?
Retention Factor
How do you calulate the retention factor (Rf)?
Rf = Distance travelled by a substance / Distance travelled by solvent
In Paper Chromatography, what is the substance also know as?
The solute
What is the name of the pencil line drawn across the chromatography paper?
baseline
Why is a pencil used to draw the line across the chromatography paper?
- Pencil is insoluble in water
- The line won’t run with the solvent
A liquid that a solute dissolves in is called a…
Solvent
How do you test for oxygen?
If oxygen is present in a test tube, a glowing splint relights when it is held inside.
- This is because oxygen supports combustion.
How do you test for hydrogen?
If hydrogen is present in a test tube, a lighted splint held near its mouth ignites with a squeaky pop.
- Hydrogen ignites in air
How do you test for carbon dioxide?
If carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white.
- Carbon dioxide reacts with calcium hydroxide solution to produce a white precipitate of calcium carbonate
How do you test for chlorine?
Damp litmus paper is bleached white when it is placed in chlorine. If damp blue litmus paper is used, the paper turns red then white.
- Chlorine is an acidic gas that also acts as a bleach
How do you test for Lithium ions?
Flame test - Crimson colour
What is the test for Sodium ions?
Flame test - yellow colour
What is the test for potassium ions?
Flame test - Lilac colour
How do you test for Calcium ions?
Flame test - Orange/Red colour
or
Add a few drops of dilute sodium hydroxide solution - White precipitate
What is the test for copper ions?
Flame test - Green colour
Add a few drops of dilute sodium hydroxide solution - Blue precipitate
What is the test for Aluminium ions?
Add a few drops of dilute sodium hydroxide solution - White precipitate (dissolves in excess sodium hyrdoxide solution)
How do you test for magnesium ions?
Add a few drops of dilute sodium hydroxide solution - white preciptiate
How do you test for Iron(II) ions?
Add a few drops of dilute sodium hydroxide solution - Green precipitate
