Uncertainty Flashcards
What is accuracy?
the degree of closeness of repeated measurements of a quantity to its actual value (theoretical & literal (peer review journal, solid method, sensitive equip.)
What is precision?
the degree of closeness of repeated measurements
How are calculations of + /- done wt significant figures?
report results to the SMALLEsT # of DECIMAL PLACES
How are calculations of x / / done wt significant figures?
report results to the SMALLEST # of SIGNIFICANT FIGURES
What is uncertainty?
confidence in the accuracy & precision of a measurement
MEASUREMENT & UNCERTAINTY SHOULD HAVE SAME # OF DECIMAL PLACES
How is the uncertainty of digital equipment found?
- record measurement given on screen
2. uncertainty = “least count” = smallest # equip. can record
How is the uncertainty of analogue equipment wt graduations found?
- record measurement wt graduations + 1 best guess
2. uncertainty = “half of least count” = half of the smallest # equip. can record
How is the uncertainty of analogue equipment stout graduations found?
BUT uncertainty is written on equip.
- record measurement to the # of decimal places in the given uncertainty
- uncertainty = uncertainty written on equip.
What is percentage uncertainty calculated?
uncertainty % = (absolute uncertainty / measurement) x 100
when using smaller equipment, smaller measurements have higher % uncertainty
therefore, it is not ideal to measure in the low range of equipment
How are measurements wt uncertainty + / -?
smallest # of decimal places used for answer
add absolute uncertainties of measurements
How are measurements wt uncertainty x / /?
answer has smallest # of significant figures
add % uncertainties
How is solubility calculated?
solubility = mass of solute / mass of solution
therefore, ADD % uncertainty
