Section 1.2- Measurement in Chemistry Flashcards
the language of science
mathematics
has to do with the consistency or reproducibility of a measurement and is closely related to a measurement’s uncertainty
precision
errors in measurement that tend to fluctuate randomly about the true value
random errors
has to do with how close a measurement is to the actual, exact value
accuracy
errors that have definite causes, such as a defective instrument, are known as
systematic errors
numbers obtained by counting are usually
certain
defined values are
certain
two types certain/exact values
counted values
defined values
because they have no uncertainty, values obtained by counting or set by a definition are
exact numbers
there is always some _______________________ in a measurement
uncertainty
a collection of compatible, related units that can be used to measure various quantities
system of measurement
the system of measurement most commonly used in the US is the
F.P.S (foot-pound-second) system
is used worldwide as the standard system of measurement for scientific and technical purposes
metric system
the metric units most commonly encountered in everyday measurement are
kilogram
meter
liter
a metric unit of mass
kilogram
metric unit of length
meter
metric unit of volume
liter
a modification of the metric system with meticulously defined standards for all units
SI
attached to the base unit’s name to change its value
prefixes
the standard SI unit of length
meter
the most familiar metric unit of volume
liter
measurements of quantities smaller than L are almost always given in
milliliters
the quantity of matter in an object
mass
the force of gravity upon an object
weight
nano
one billionth
n
10^-9
micro
one millionth
u with a backwards tail
10^-6
milli
one thousandth
m
10^-3
centi
one hundredth
c
10^-2
kilo
one thousand
k
10^3
mega
one million
M
10^6
measures the compactness of matter
the ratio of a substance’s mass to its volume
density
represents density
rho
equation for density
p= m/V
the same amount of weight will have the same amount of
mass
density units
g/mL
g/cm^3
in chemistry, temperature is most often measured in
degrees Celsius
freezing point
C= 0
F= 32
K= 273.15
boiling point
C=100
F=212
K= 373.15
formula for converting F to C
Tc= 5/9 (Tf-32)
formula for converting C to F
Tf= 9/5Tc + 32
the coldest possible temperature is
the temperature at which molecules cease vibrating
absolute zero
is that same size as a degree Celsius
kelvin (K)
formula to convert K to C
Tc= Tk-273.15
the basic unit of time
second
to perform unit conversions, you should use the technique of
dimensional analysis
a fraction that equals 1 and has different units in the numerator and denominator
conversion factor
