C2) Experimental Techniques Flashcards
which equipment is used to measure time and what are the units? [2]
- stopwatch
- seconds
which equipment is used to measure temperature and what are the units? [2]
- thermometer
- degrees celsius
which equipment is used to measure mass and what are the units? [2]
- mass balance
- grams
which 3 equipments are used to measure volume of a liquid and what are the units? [4]
- measuring cylinder, volumetric pipette, burette
- cm^3
which equipment is used to measure volume of a gas and what are the units? [2]
- gas syringe
- cm^3
which process is used to separate 2 or more solids that are soluble? [1]
paper chromatography
how do you calculate Rf values in paper chromatography? [1]
distance moved by solute + distance moved by solvent
define a pure substance [1]
a substance that contains a single element or compound not mixed with any other substance
describe 3 ways that the purity of a substance can be assessed [3]
- melting point
- boiling point
- chromatography
describe how melting point/boiling point can be used to asses purity [2]
- a pure substance will have a sharp melting/boiling point.
- an impure substance will melt over a temp range.
describe how chromatography can be used to assess purity [1]
a pure substance will only produce one well defined spot on a chromatogram.
describe 2 examples of where purity of a substance is important [2]
manufacture of compounds used in drugs & food additives
what is filtration used for? [1]
to separate an insoluble solid from a liquid
what is the filtrate in filtration? [1]
the liquid or solution that has passed through the filter
what is crystallisation? [1]
when a liquid that contains a dissolved salt is evaporated to leave the salt behind.
