Lab Measurement Precision and Data Recording in
Chemistry Questions and Answers with Complete Solutions
UPDATED!!!
Where should the precision of a measurement come from? -
ANSWER From the glassware itself (if labeled).
What should you do if no precision is written on the glassware?
- ANSWER Use the general precision values provided in the lab
manual.
How should you record volumes and masses in your notebook?
- ANSWER Record values to the correct number of decimal
places based on precision.
Example: Measuring 10 mL with a 10 mL graduated cylinder
(±0.1 mL), how should you write it? - ANSWER 10.0 mL
Do you need to include the absolute precision next to your
measurement? - ANSWER No, as long as the significant digits
are correct.
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Do you need to include the uncertainty in the equipment
name? - ANSWER No (e.g., "10 mL graduated cylinder" is
sufficient).
Precision of a burette? - ANSWER ±0.01 mL
Precision of a 10 mL graduated cylinder? - ANSWER ±0.1 mL
Precision when subtracting two readings from a 10 mL
graduated cylinder? - ANSWER ±50% of the difference between
the lines
Precision of a 50 mL graduated cylinder? - ANSWER ±0.4 mL
Precision when subtracting two readings from a 50 mL
graduated cylinder? - ANSWER ±50% of the difference between
the lines
Precision of a beaker or graduated flask? - ANSWER ±5% of
capacity