Formula: Experimental - Theoretical X 100
Theoretical
Experimental = Values obtained from the lab.
Theoretical = Values obtained from some authority -> book, table, list, official, etc.
(+) A positive percent error indicates your experimental values are
______________ than the theoretical values.
(-) A negative percent error indicates your experimental values are
______________ than the theoretical values.
Determine the percentage error in the following problems. Show all your work!
1. Experimental Value: 1.24 g
Theoretical Value: 1.30 g
2. At a track meet, you time a friend running 100 m in 11.00 seconds. The officials
time her at 10.67 seconds. What is your percentage error?
3. A standard 20.OOg mass is used to check the accuracy of a laboratory balance.
The balance indicates a mass of 19.81 g when a standard mass is measured.
What is the percent error of this measurement?
4. In 1.000 hour, as measured by a very accurate chronometer, a wristwatch
measured an elapsed time of 1 hour and 12 seconds. What is the percent error
in the time measured by the wristwatch?
5. The mass of a certain chemical was determined by a very precise balance to be
1.4200 g. The same mass of a chemical was measured on a less precise balance
and found to be 1.43 g. What is the percent error for the less precise balance?
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11. Clyde Clumsy was directed to weigh a 500 g mass on the balance. After
diligently goofing off for ten minutes, he quickly weighed the object and
reported 458 g.
12. Pretty Patty Pestilence had casually recorded her grades for the nine weeks
in her notebook. She concluded she had 250 points out of 300 for the
grading period. However, Miraculous (chem teacher) determined she had 225
points out of 300 and awarded her a "C" for the grading period.
13. Drew D. Dingaling came to Miraculous with a problem. Drew was told to
measure 50 cm of copper wire to use in an experiment. Since his ruler only
measured to 45 cm he used this amount of wire and his experiment was a
failure.
14. Willomina Witty was assigned to determine the density of a sample of nickel
metal. When she finished, she reported the density of nickel as 5.59 g/ml.
However, Miraculous knew the density of nickel was 6.44 g/ml.
15. An experiment to determine the volume of a "mole" of a gas was assigned to
Barry Bungleditup. He didn't read the experiment carefully and concluded
the volume was 18.7 liters. Miraculous knew he should have obtained 22.4
liters.
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