erlenmeyer flask/beaker
can record to the 50s (like 250), not accurate or precise, looks like a clear cup
volumetric flask
can only record one measurement (smtg like 100.00 mL) but it is VERY precise and accurate with this measurement, looks like tube that expands into a bigger base
burette/pipette
can record to the 10ths and 1s (6.52), precise and accurate, looks like a tube with a rectangle on the bottom with a triangle attached
graduated cylinder
can record to the 1s (2.50 mL), accurate and precise, looks like a cup with a circle on the bottom
precision
being exact/all bullets in the same place but not necessarily on bullseye
accuracy
being close or true to a correct value/bullets are averagely spaced around the bullseye
percent error
what accuracy is assessed with...eq: actual-true
------------- x100%
true
standard deviation/95% confidence interval
what precision is assed with...annoying to do by hand so use excel
systematic error
Error that shifts all measurements in a standardized way. Decreases accuracy. Can result in bias
random error
Error that is due to chance and is not standardized. Decreases precision.
scientific method
s series of steps scientists perform when completing an experiment
ask a question
1st step of scientific method, provides u with stmg u wish to know
do research
2nd step of scientific method, find out what is already known
construct hypothesis
3rd step of scientific method, make an educated guess about what the results of the experiment will be
design a procedure
4th step of sci method, develop step by step directions
collect data
5th step of scientific method, gather your info
analyze data
6th step of sci method, assess what your data means; this might involve calculations or graphs
draw conclusions
7th step of sci method, tells the story that your data provides you with and answers your original question
cyclical process
goes over and over again, what the sci method is, when experiments end new questions rise and the process begins anew
how we r suppose to do lab write ups
purpose statement (contains "to"), hypothesis ("if...then...because..."), materials list, procedure, data (contains tables, calculations, and graphs), results (para form), conclusion (restate purpose, summarize procedure, restate results)
significant figures
all known digits in a measurement plus one estimated digit
which #s are sig figs
all numbers 1-9
sandwiched zero-s
counts as sig fig (1003 has 4 sig figs)
rule with sigs figs with a decimal/bar
if u add a bar/decimal the all the numbers before decimal count as significant (1000. has 4 sig figs while 1000 only has 1)
right and right rule
zeros to the right of the decimal and are also to the right of a sig fig are significant (2.50 has 3 sig figs while 0.025 has 2 sig figs)
place holder zeros
hold value of the number, are not significant (250 has 2 sig figs and 1 place holder 0)
what happens to precision when math operations occur
when calculations are preformed, error can be compounded. therefore the precision of the answer to a calculation is reliant upon the lest precise measurement used in the calculation (relates to why sig figs are important)
precision rule in adding and subtracting
amount of decimal places In final answer depends on the least number of decimal places of both numbers in the original equation
precision rule in multiplying and dividing
amount of sig figs depends on the least number of sig figs found of both numbers in original equation
scientific notation
a way of writing really big numbers in a more manageable form
rules of sci not
-can only have one digit to the left of the decimal (1.34)
-only sig figs are included in the mantissa
-number of power of 10 relates to how many times the decimal was moved
positive exponent in sci not
number is large so decimal will move to the left
neg exponent in sci not
number is small so decimal will move to the right
mantissa
the numbers left the times 10 part (idk what this even means but that's how it was in the notes)
standard notation
just opposite sci not, a number how we would usually write it
measurement
a quantity that has both a number and a unit, determines amount
unit
used to express the size of a measurement
matter
anything that has mass and takes up space (people, objects, air/atoms, water), usually has mass and volume
not examples of matter
light heat energy
qualitative
data in the form of words, matter can be described like this
quantitative
data that is in numbers, matter can be described like this
SI units
systematic international units...standard unit of measurement for everyone
mass
a measure of the amount of matter in an object (g,mg,kg)
volume
the amount of space an object takes up (mL, L, qt)
density
amount of mass that occupies a volume, intensive property, low ____ will float, high ____ will sink
density equation
D=m/v
qualitatively compare density example
if a marble has a low density than it will float because it is less dense than the water. if a marble has a high density it will sink because it is more dense than water
why do measurements need units
to determine how big/small the measurement is and what kind (like is it liquid or length or weight or whatever)
You gals are smart and r gonna do so good
don't stress about this and if your up late go to bed cause sleep is good...bye have a good day mwah????
also jus one more thing
this is literally everything she gave us like everything from the chem pack sheet and notes we took in class so if we do bad//the test is on random shit imma throw hands but she told me she usually curves tests so yay!