Experimental Chem Flashcards
gas collection - 3
insoluble: displacement of h2o; co2, h2, o2
more dense > air: downward delivery; cl2, hcl
less dense > air: upward delivery; nh3, h2
drying agents - 3
conc. sulfuric acid: acidic gases, cl2, hcl
quicklime (calcium oxide): alkaline gases, nh3
fused calcium chloride: most gases, h2
gas solubilities - 9
high:
- nh3
- hcl
- so2
- cl2
low:
- co2
- co
- o2
insol:
- h2
- he
- n2
classification separation technique
s+s
s+l: sol/insol SOLID
l+l: miscible/immiscible LIQUID - can mix/not
separation techniques - 9
- MISCIBLE LIQUID - Fractional Distillation
- IMMISCIBLE LIQUID - Separating Funnel
- SUBLIMATION - Sublimable/not
- PAPER CHROMATOGRAPHY - Small, dissolved
INSOL S+L
- Filtration
SOL S+L
- DECOMPOSE ON HEATING/SOLUBILITY CHANGE W/ TEMP: Crystallization
- WATER OF CRYSTALLISATION: Evaporation
- REMOVES LIQUID - Simple Distillation
crystallisation process
- soln heat to saturation
- soln cooled -> crystals
- filtered 4 crystals - residue
- washed w/ small amnt cold h2o
- dried between filter papers
simple distillation process
1. soln boils, vapour enter condenser
2. cooled, becomes pure, collected in beaker
3. other becomes other
fractional distillation process
1. soln boils, vapour enter condenser
2. liquid lower bp vapourises, rises; higher bp condenses, falls back
3. lower bp condense all collected, temp UP quickly, collect higher bp
apparatus for frac distillation
- boiling chips: ensure smooth boiling
- thermometer: bulb @ condenser opening
- condenser: cold, h2o enter bottom ensure vapour entirely condenses
- fractionating column: allows higher bp to fall, lower to rise
good practices 4 chromatography
- starting line draw w/ pencil, ink dissolves
- spots small & concentrated for distinct separation
- solvent line near top to ensure dyes fully separate
retention factor (Rf) 4 chromatography
substance distance/solvent
detect colourless gases 4 chromatography
locating agent used, reacts w/ substances to form visibly coloured
(UV LIGHT ALSO CAN)
