quiz 1 Flashcards
Molarity
moles solute/1 liter solution
mass fraction
g solute. g solution x100
parts per thousand (ppth)
g solute/g solution x1000
parts per million (ppm)
g solute/g solution x10^6
parts per billion by mass (ppb)
g solute/g solution x 10^9
what is the big assumption for all aueous solutions?
1 mL/g
what is ppm equal to
ug/g, mg/L, ug/mL
what is ppb equal to
ng/g, ug/L, ng/mL
whats the difference between implicit and explicit uncertainty
the uncertaintiy is very clear stated in explicit uncertainity
the uncertainty is implied by the significant figures (ex: a value of 400 has an uncertaintiy of +- 100
while a value of 399.32 has an uncertainty of 0.01)
what would be the multiplier of RSD (ppm)?
std/(mean) x (10^6)
what is absolute uncertainty?
it expresses the margin of uncertainty associated with a specific measurement
what is relative uncertainty
it compares the absolute uncertainty with the measurement itself
what is determinate error
it is caused by the way you make a measurement, it always occurs in one direction and is constant
what is an indeterminate error
it is harder to detect but can occur in either direction and is not constant, it is always present and random
what type of error is a precision error?
Indeterminate
what is error
the difference between a single measurement and its expected value
what is uncertainty
it expresses the range of possible values for a measurement or result
what is the absolute uncertainty
found by the UNC equations
what is the relative uncertainty
UNC equation result divided by the # found originally
what is absolute error
experimental - actual value
relative error is what
(experimental-actual) divided by actual
what is the uncertainty in this? 10.00 ± 0.02
0.02
A 25 mL pipette consistently delivers 25.031 ± 0.009 mL. Is the error determinate, indeterminate or both?
Determinate: 0.031
indeterminate ± 0.009mL
what does the uncertainty express
it accompasses a range of what the values could be
