Temperature
• Measurement of kinetic energy of atoms or
molecules
Temperature Scales
Water
Boils
212
100
373
Water
Freezes
32
0
273
- 452
- 273
0
Absolute
Zero
Fahrenheit (°F)
Celsius (°C)
– Based on
boiling &
freezing point
of water
Kelvin (K)
• Kelvin temperature scale
– Based on absolute zero
– Absolute zero is when all motion of atoms
stop!
273 + °C = K
• Accuracy
– How close a measured value is to the
accepted value or target
• Precision
– How close a series of measurements are to
one another
1
2
3
4
Accurate?
Precise?
Accurate = means close to the bull’s eye
Precise = means shots are close to one
another
Practice
• Density of water is 1 g/mL
• Student one
Student 1
– Accurate?
– Precise?
• Student two
– Accurate?
– Precise?
Student 2
1.03
0.89
0.98
0.89
1.01
0.87
0.99
0.88
Percent Error
• Ratio of error to the accepted value
• Can be positive or negative
• We like to within 5% 
error
% error 
100
accepted value
(experimental  accepted )
% error 
100
accepted value
Percent Error Practice Problems
1. The boiling point of water is 100°C. During an
experiment, water came to a boil at 97°C according to
the thermometer that was being used. What is the
percent error?
% error 
error
100
accepted value
(experimental  accepted )
% error 
100
accepted value
Percent Error Practice Problems
2. An experiment was performed to determine the
density of water. The results of the experiment
showed that water had a density of 1.15 g/mL(real
value is 1.0 g/mL). What is the percent error?
% error 
error
100
accepted value
(experimental  accepted )
% error 
100
accepted value
Percent Error Practice Problems
3. An experiment was conducted to find the mass of
one mole of carbon atoms. The results of the
experiment showed that a mole of carbon atoms has a
mass of 15.78g. The actual value is 16 grams. What
is the percent error?
error
% error 
accepted value
100
(experimental  accepted )
% error 
100
accepted value
Percent Error Practice Problems
4. An experiment performed to determine the density of
lead yields a value of 10.95 g/cm3. The actual value
for the density of lead is 11.342 g/cm3. Find the
percent error.
error
% error 
accepted value
100
(experimental  accepted )
% error 
100
accepted value
Percent Error Practice Problems
5. Find the percent error in a measurement of the
boiling point of bromine if the experimental value is
40.6°C and the actual value is 59.35°C.
% error 
error
100
accepted value
(experimental  accepted )
% error 
100
accepted value