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chapter 20: Experimental techniques and chemical analysis - Coggle Diagram
chapter 20: Experimental techniques and chemical analysis
measure volume
measuring cylinder, burette, pipette
use gas syringe to measure the volume of gas
measuring mass
beam balance / electronic balance
measuring time
stopwatch
measuring temperature
mercury thermometer/ alcohol temperature
method to collect gas
displacement of water
collect INSOLUBLE or slightly soluble gases in water
gas go through the delivery tube into the gas jar
gas jar that is full of water was place in a bowl of water
ex. hydrogen, carbon dioxide, oxygen
downward delivery
collect gases that are SOLUBLE in water and DENSER than air
delivery tube was placed inside the gas jar
gas go through and went down the gas jar ( gas collected)
ex. chlorine, hydrogen chloride, sulfur dioxide
upward delivery
collect gases that are soluble in water and LESS DENSE than air
gas jar was placed upside down and the delivery tube was placed inside
ex. ammonia
mixture- made up of 2 or more substances that are NOT CHEMICALLY COMBINED
separate solid from a liquid
filtration (separate insoluble solid
the filter funnel act as a sieve
residue- solid remains on the filter paper
filtrate- liquid or solution pass through the filter paper
evaporation to dryness
use evaporating dish & tripod stand
not always pure, have to wash the filtrate with distilled water
crystallistion (separate soluble solid)
used to obtained PURE SOLID from its solution
water is removed
heating is stop when a hot SATURATED SOLUTION is formed
if the saturated solution is cooled, the dissolved solid will form as pure crystals
separating solids
solvent
the LIQUID that dissolves the solute
solute
the substance that is dissolved
sublimation
used to separate a solid that sublimes from one that does not ( change directly into vapour when heated, typically forming a solid deposit again on cooling.)
separating a liquid from a solution
simple distillation (separate liquid & a soluble salt from a solution)
lowest boiling point evaporates first, much lower than the dissolved solid
only can separate things with very diff boiling points
fractional distillation (separate mixtures of liquid at diff boiling points)
separate liquids that have boiling points that are close together
most volatile liquid in the mixture evaporate first, other will also evaporate but the column is cooler towards the top, so they will get part of the way up and run back down
chromatography
separate 2 or more dissolved solids in a solution
color substances separate if have diff solubilities in the solvent
use a dropper, must use pencil to draw baseline
to check the purity of a substance, if its pure only give one spot
locating agent use to produce coloured spots if cannot see