IB chemistry 11 Flashcards
bakers, test tubes, watch glasses, and flasks are all examples of ________ glassware
qualitative
graduated cylinders, volumetric flasks, pipettes, and burettes are all examples of _______ glassware
quantitative
what does it mean for an instrument to be volumetric?
meant for measuring; high accuracy
beakers
heat and mix chemicals, pour
test tubes
store, heat, mix chemicals
watch glasses
large surface afea for small liquids to evaporate/ crystalize
flasks
mix contents without spilling; direct heating
erlenmyer flask
to swirl / mix contents + add direct heat
round bottom flask
to heat throughout, to distill
volumetric (looks like bong)
mixing + extremely precise solutions , titrations, precision measurements
graduated cylinder
semi precise, to deliver to another container
burette
deliver precise liquids ; uses stopcock
funnel
to dispense different powders/liquids
zeros between sigs are
sig
final zero after decimal
sig
trailing zero in decimal
sig
leading zero
not sig
random error
unpredictable, random, cannot correct
systematic error
correctable, consistently wrong - due to experiment/machine error
absolute uncertainty
amount by which the measurement differs - final answer times decimal
relative uncertainty
uncertainty/value
percent uncertainty
uncertainty/value (100)
percent error
experimental-actual/actual (100)
absolute error
measured-accepted
determining uncertainty
analogue : half the smallest
digital: smallest increment
adding/ sub
add uncertainties
div / mult
calculate percent uncertainty of each, add together, multiply value by the decimal
average
average uncertainties
atom economy
desired product /total product
green chemistry principles
- Prevent waste
- Maximize atom economy
- less hazardous chemical syntheses
- Design safer chemicals and products
- Use safer solvents and reaction conditions
- Increase energy efficiency
- Use renewable feedstocks
- reduce derivatives
- Use catalysts
- Design chemicals and products to degrade
- Analyze in real time to prevent pollution
- Minimize the potential for accidents
higher atom economy is
preffered
percent error> uncertainty
inaccurate