Chemistry test unit one
Accuracy
how close a measurement comes to the true value
Percision
how close a series of measurments are to each other
where do we measure on a graduated cylinder?
the bottom of the meniscuis (picture)
what do we measure to?
the value you read plus one estimated digit (example)
Always include:
UNITS
Absolute error equation
actual-observered (absolute value)
percent error
Absolute error/actual
what can errors be?
positive or negative
what are percents always?
positive
Sig fig
a measurement that includes all certain digits plus one estimated digit
sig fig rule 1:
non zero numbers are always significant
sig fig rule 2
zeros between numbers are always significant
sig fig rule 3
leading zeros are NEVER significant
sig fig rule 4
trailing zeros are significant only when behind a decimal (example)
sig fig rule 5
real numbers (apples) are unlimited sig fig
place holder zeros
never significant
purpose of sig figs
more sig figs, more accurate
when adding or subtracting w/ sig figs:
keep the least amount of decimal places in your final answer
when multiplying or dividing w/ sig figs:
keep the least amount of sig figs from the inputted values in the final answer
scientific notation equation
coefficient * 10 raised to a power
coefficient
between 1-10
negative power
decimal
length
meter (m)
mass
gram (g)
volume
liter(L)
time
seconds (s)
temperature
celcius(C)
K H D B D C M
King Henry Died By Drinking Chocolate Milk
k
kilo, *1000
h
hecto, *100
da
deca, *10
base unit
1
d
deci, *0.1
c
centi, *0.01
m
milli, *0.001
weight
force of gravity on an object
mass
amount of matter in object
temperature
measure of average kinetic energy of the particles in the substance
what does temp determine?
the direction of heat transfer
Celcius vs Kelvin
both scales change at tge same rate
C freezing and boiling points
F: 0
B: 100
K freezing and boiling points
F: 273k
B:373k
coverting k to C
k-273
coverting C to k
C+273
conversion factor
a ratio of equivalent measures
dimensional analysis
canceling out units to covert from one unit to another
conversion rule 1:
write given w/ units
conversion rule 2:
put given over 1
conversion rule 3:
write in units for your conversion so that they cancel with the units from your given
conversion rule 4:
fill in # values for your conversion
conversion rule 5:
multiply anything in the numerators and divide by anything in the denominators
conversion rule 6:
cancel units
conversion rule 7:
check sig figs and units on solution
what are the sig figs at the start and end of conversion?
same sig figs at start and end
use base unit for
middle man when converting to really small values