chem review quiz

accuracy

how close the data is to the accepted value

precision

how close data values are to each other

all nonzero digits are

significant

zeroes between non zero digits are

significant

zeroes to the left of the first nonzero digits

are NOT significant (just indicates where decimal point is)

zeroes to the right of a decimal point is

significant

zeroes NOT to the right of a decimal point

arent necessarily significant unless theres a decimal point

addition and subtraction w/ sig figs

final value rounded to fewest number of DECIMAL PLACES

multiplication and division w/ sigfigs

final value rounded off to same AMOUNT OF SIGFIGS (regardless of decimal placing) as the number w/ fewest number of sigfigs

density =

mass / volume (depends on type of matter and not amount of it)

exact number

zero uncertainty; comes from counting objects or defined conversion values; treated as infinite significant figures

inexact number

physical measurements (e.g. weight/length) that always have some uncertainty or error based on tool used

watch glass

rounded piece of glass shaped like lens to evaporate small amounts of liquid; also used to cover beakers

what type of equipment is this?

erlenmeyer; not used to measure liquid volume because cone shape makes measuring difficult

magnetic stirrer

used to dissolve solids in liquids (uses magnetism to stir and you put the magnet inside the glass)

how to read a meniscus

read the bottom of the meniscus

burette

graduated piece of glassware used to measure precise amounts of liquid

pipette and bulb

used to measure exact volumes of liquid (more precise than graduated cylinders)

what type of equipment is this?

beaker; used only for estimates and holding liquids (not accurate volume measurements)

what type of equipment is this?

volumetric flask; calibrated to precise volumes (best flask type thing for measuring out volumes)

filter paper

used w/ glass funnel to separate solids from liquids → fold paper in half then fold in half again; then open into cone

hot plate

electrical device used to heat solutions

boiling stones

small stones added to liquids to make them boil more smoothly; prevents bumping (hot solution splashing out of beaker)

stirring rod

helps you pour liquid from one contained to another as liquid flows down the rod

crucible

dish used for chemical reactions and analysis; supported by a clay triangle and ring stand

what kind of equipment is this?

graduated cylinder; used for accurate measurements of liquid

wire guaze

square piece of metal mesh used to support a beaker on metal ring; can take extensive heating

which of the following is best for measuring volume vs just holding liquids?
beaker, erlenmeyer flask, graduated cylinder, volumetric flask

graduated cylinder and volumetric flask