ERRORS AND UNCERTAINTIES Flashcards
What is an error?
The difference between an experimental value and the accepted or correct value.
What is accuracy?
A measure of how close values are to the accepted of correct value.
What is precision?
A measure of how close values are to each other.
What is a random error?
Errors caused by unpredictable variations in conditions.
What is a systematic error?
Errors that are constant or predictable, usually because of the apparatus used.
What is a measurement uncertainty?
The potential error involved when using a piece of apparatus to make a measurement
What is the percentage uncertainty?
In an experiment, the actual measurement uncertainty multiplied by 100 and divided by the value recorded.
What is the uncertainty of burette?
±0.05 cm³
What is the uncertainty of a pipette?
±0.06 cm³
What is the uncertainty of a volumetric flask?
±0.3 cm³
The percentage uncertainty in using a balance depends on?
- The precision of the balance, e.g. number of decimal places to which balance can read.
- The mass being weighed (percentage uncertainty will be greater for a smaller mass.)
