I am making a 0.1 M KCl (molar mass 74.551) solution for an experiment. To measure the mass of the KCl, I will use an analytical balance that is only accurate to ± 0.01 g. I place a piece of paper on the balance and set the tare to read 0.00. I then put the KCl on the balance until it reads 6.79 g. What is the uncertainty in this mass?
Table of contents
- 1. Chemical Measurements1h 50m
- 2. Tools of the Trade1h 17m
- 3. Experimental Error1h 52m
- 4 & 5. Statistics, Quality Assurance and Calibration Methods1h 57m
- 6. Chemical Equilibrium3h 41m
- 7. Activity and the Systematic Treatment of Equilibrium1h 0m
- 8. Monoprotic Acid-Base Equilibria1h 53m
- 9. Polyprotic Acid-Base Equilibria2h 17m
- 10. Acid-Base Titrations2h 37m
- 11. EDTA Titrations1h 34m
- 12. Advanced Topics in Equilibrium1h 16m
- 13. Fundamentals of Electrochemistry2h 19m
- 14. Electrodes and Potentiometry41m
- 15. Redox Titrations1h 14m
- 16. Electroanalytical Techniques57m
- 17. Fundamentals of Spectrophotometry50m
3. Experimental Error
Uncertainty
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Determine the absolute and relative uncertainty to the following multiplication and division problem.
1.12(±0.01) x 0.546 (±0.01) / 3.12(±0.02) x 1.12 (0.03)
A
0.003 absolute; 0.01 relative
B
0.03 absolute; 0.006 relative
C
0.006 absolute; 0.03 relative
D
0.006 absolute; 0.01 relative

1
Identify the given values and their uncertainties: 1.12(±0.01), 0.546(±0.01), 3.12(±0.02), and 1.12(±0.03).
For multiplication and division, the relative uncertainties are added. Calculate the relative uncertainty for each value by dividing the absolute uncertainty by the measured value.
Add the relative uncertainties of all the values involved in the multiplication and division to find the total relative uncertainty.
Multiply the total relative uncertainty by the calculated result of the multiplication and division to find the absolute uncertainty.
Express the final result with its absolute and relative uncertainties, ensuring the significant figures are consistent with the precision of the measurements.
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