Further Analysis Flashcards
Pure substance
A single element or compound not mixed with any substance
Formulation
A mixture of substances designed to be a useful product
Impure substance
A substance that contains other substances (impurities)
How to identify pure vs impure substance
A pure substance has a fixed melting and boiling point. An impure substance has a range of temperatures.
Hydrogen gas test
Lit splint in test tube → gas burns with squeaky pop
CO2 test
Bubble gas through limewater → White prep
Cl test
Damp blue litmus paper → Bleaches
Alkene
Bromine water → Orange to colourless
Acid/Alkali
Indicators colour change
pH
Universal indicator → colour change
Acid
Add metal carbonate
Bubble gas through limewater
If CO2 produced goes cloudy
Excited electrons
- When provided with energy, electrons are promoted to higher energy levels in the atom, e.g. thermal energy
- They then drop down to ground state, releasing energy.
Why do excited electrons produce light
- Different atoms have different electron arrangements, giving off different light frequencies.
- Some frequencies are in the visible region of the EM spectrum.
Li+ (flame)
Crimson
Na+ (flame)
Yellow
K+ (flame)
Lilac
Ca 2+ (flame)
Orange/Red