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34 terms

Chemistry Chapter 3

10/23/2011
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Base unit of length
meter- m
base unit of mass
kilogram-kg
base unit of temperature
kelvin-K
base unit of time
seconds-s
Amt of substance base unit
Mole-mol
Kilo
1000x unit
(1000m=1 km)
deci
10dm= 1 meter
10
centi
100cm= 1 meter
100
milli
1000mm= 1 meter
micro
1 x 10^6 um= 1 meter
nano
1 x 10 ^9= 1 meter
pico
1 x 10 ^12 pm= 1 meter
Conversion factors
fractions that represent the same unit (where the numerator and the denominator are equal to each other)
ex. 100 cents/1 dollar
How are conversion factors used?
used to solve any kind of problem
International System of Units
the revised version of the metric system, adopted by international agreement in 1960
The five SI base units commonly used by chemists are the meter, the kilogram, the kelvin, the second, and the mole.
Weight
a force that measures the pull on a given mass by gravity. It is a measure of force, it's different from mass, which is a measure of the quantity of matter.
Kelvin Scale
the freezing point of water is 273.15 kelvins (K), and the boiling point is 373.15 K. Notice that with the Kelvin scale, the degree sign is not used.
The zero point on the Kelvinscale, 0 K, or absolute zero, is equal to −273.15°C.
Energy
the capacity to do work or to produce heat
joule (J)
the SI unit of energy. It is named after the English physicist James Prescott Joule
calorie (cal)
One of these is the quantity of heat that raises the temperature of 1 g of pure water by 1°C
Dimensional Analysis
a way to analyze and solve problems using the units, or dimensions, of the measurements. The best way to explain this problem-solving technique is to use it to solve an everyday situation.
Density
the ratio of the mass of an object to its volume.
densisty= mass/volume
Measurement
a quantity that has both a number and a unit, fundamental to the experimental sciences
scientific notation
a given number is written as the product if two numbers: a coefficent and 10 raised to a power
Accuracy
a measure of how close a measurement comes to the actual or true value of whatever is measured
Precision
a measure of how close a series of measurments are to one another
To evaluate accuracy...
measured value compared to the correct value
To evaluate precision...
compare the values of two or more repeated measurments
Accepted Value
the correct value based on reliable references
Experimental Value
the value measured in the lab
Error
the difference between the experimental value and the accepted value
Error= experimental value - accepted value
Percent Error
The absolute value of the error divided by the accepted value, multiplied by 100
% error= |error| / accepted value x 100
Find the Kelvins from Celcius
K= C + 273
Find the Celcius from Kelvins
C= K - 273