C8-chemical Analysis Flashcards
Define pure substance
Something that contains one type of element or compound, e.g. pure water, pure sodium chloride
True or false pure substances melt and boil at specific temperatures
True
True or false having impurities in samples (e.g. salt and water) will lower the melting point but increase the boiling point
True
What is a formulation?
A mixture that has been designed to do something useful
What are some examples of formulations?
Fuels, cleaning agents, paint, medicines, alloys, fertilisers, food and drink
What are the two phases why chemicals travel different rates in paper chromatography ?
Mobile phase and the stationary phase
Mobile phase in paper chromatography
Molecules can move, always liquid or gas, if more time is spending this phase it will move faster and be higher up the paper. In this case it would be the solvent
Stationary phase in paper chromatography
Molecules can’t move, usually solid or thick liquid, in this case its the paper, if more time is spent in this phase it will move slow slower and be lower down the paper nearer the baseline and will be less soluble.
How do you calculate the RF value?
Distance travelled by the substance / distance travelled by the solvent
What is the test for chlorine?
Dampen litmus paper and put the litmus paper in the test tube full of the sample gas
If chlorine is present, paper should turn from blue to white
What is the test for oxygen?
Put a glowing splint at the end of a test tube full of the gas sample.
If oxygen is present, the oxygen will relight the glowing splint
What is the test for hydrogen?
Put a burning splint in a test tube full of the gas sample.
If hydrogen is present, you will hear a squeaky pop
What is the test for carbon dioxide?
Put your gas sample in one tube and lime water in another tube. Bubble the gas sample through lime water.
If carbon dioxide is present, the lime water will turn cloudy.
What color flame do lithium compounds produce?
Crimson red flame
What color flame do sodium compounds produce?
Yellow flame
What color flame do potassium compounds produce?
Lilac flame
What color flame do calcium compounds produce?
Orange red flame
What color flame do copper compounds produce?
Green flame
