chapter 1 experimental chemistry Flashcards
what is the si unit and apparatus used for time
seconds s
digital or analogue stopwatch
what is the si unit and apparatus used for temperature
kelvin K
thermometer
what is the si unit and apparatus used for length
metre m
measuring tape or metre rule
what is the si unit and apparatus used for mass
beam balance or electronic balance
what is the si unit and apparatus used for volume
cubic metre (cm3)
1. pipette (accurate fixed volumes)
2. volumetric flash (larger accurate fixed volumes)
3. measuring cylinder (up to 0.5)
4. burette (up to 0.05)
name the 2 methods of collecting gas and their requirements
- water displacement
- insoluble to slightly soluble - downward delivery
- denser than air - upward delivery
- less dense than air
state the 3 method of drying gas and gases that do not work with it
- concentrated sulfuric acid
- ammonia - quicklime calcium oxide
- carbon dioxide - fused calcium chloride
- ammonia
what does magnetic attraction do
separate a magnetic solid from non magnetic solids
what does sieving do
separate solids with different particle size
what does using suitable solvents do
separate mixtures in which only one of the solids is soluble in solvent
what does sublimation do
separate a mixture in which only one of the substances changes from solid to gaseous state directly when heated
how does filtration work
used to separate insoluble solids from liquids
how does evaporation to dryness work
separate dissolved solid from its solvent until all solvent has vaporised
what does crystallisation do
obtain a pure solid from its saturated solution
describe the process of crystallisation
- heat solution in an evaporating dish to saturation
- cool solution gradually until crystals appear
- pour the mixture through a filter funnel to collect crystals
- wash crystals with cold distilled water and dry between sheets of filter paper
what does simple distillation do
separate pure solvent from its solution
describe how simple distillation takes place
- salt water is heated and boiling chips are added for smooth boiling and when the water boils and vaporises it enters the condenser
- water vapour cools in the condenser and pure water is collected as distillate
- as more water vaporises a solid residue of salt remains
what does a separating funnel do
used to separate immiscible liquids (heterogenous mixtures)
what does chromatography do
used to separate mixture of substances which have different solubilities in a given solvent
how do you find Rf value
distance travelled by substance/distance travelled by solvent
what to do in chromatography if the substance is colourless
apply a locating agent
what does fractional distillation do
it is used to separate miscible liquids with different boiling points
how does fractional distillation occur
- solution is heated until both liquids vaporise and rise up to the fractionating column
- since water has a higher boiling point than water, water vapour condenses back into the flash
- ethanol vapour enters the condenser and cools and condenses into a liquid
- liquid ethanol is collected as distillate
what is a pure substance
a substance with a specific melting or boiling point
