Analytical Chemistry Book Chapter 3
percent relative uncertainty
100 x the relative uncertainty.
3
10^6.142 has how many significant digits in the answer (antilog)?
2 (since x 10^2)
339 has a characteristic of what?
error
Accuracy is nearness to the "truth" since somebody must measure the true value an there is ____ associated with every measurement.
precise, accurate
An ideal procedure is both ___ and _____, though it is possible to have either without the other.
systematic
An uncalibrated buret causes ______ error.
relative, absolute
Antilog ____ uncertainties are proportional to ___ uncertainties.
certainty
Conclusions can be expressed with a high or a low degree of confidence, but never with complete ______.
eliminated, experiment
Random error cannot be _____, but it may be reduced by a better _____.
positive, negative
Random error has an equal chance of being ______ or _______.
indeterminate
Random error is also called ______ error.
unitless
Relative uncertainty is ______.
absolute uncertainty, measurement
Relative uncertainty= ___ ____ / magnitude of ___
final
Rounding should only be done on the ___ answer, not intermediate results, to avoid accumulating round-off errors.
precision
Significant figures- the minimum number of digits required to express a value in scientific notation without loss of _______
reproducible, corrected
Systematic error is ____ and in principle can be discovered and _____.
consistent, detected, corrected
Systematic error is ____ error that can be ____ and _____.
determinate
Systematic error is also called _____ error.
uncertainty
The Real Rule for Significant Figures means that the result of a calculation ought to be written in a manner consistent with its ___.
uncertain, significant
The Real Rule for Significant Figures states that the first ____ figure is the last ____ figure.
power of 10
The __ _ __ has no influence on the number of figures retained in multiplication or division.
Real Rule for Signficant Figures
The ___ ___ ___ ____ ___ states that the first digit in the absolute uncertainty is the last digit in the answer.
exponent
The characteristic in a number refers to the ____ in its logarithm.
significant, uncertainty
The last ____ digit (farthest to the right) in a measured quantity always has some associated ____.
1
The minimum uncertainty is +/- __ in the last digit.
mantissa, significant figures
The number of digits in the ____ of logx equals the number of _____ _____ in x.
antilog, mantissa
The number of digits in the ____ of x equals the number of significant figures in the ____ of x.
true
There is no way to measure the ___ value of anything.
measured, digital, integers
There is uncertainty in any ___ quantity, even if the measuring instrument has a ____ readout that does not fluctuate. However, _____ are exact (can't split 4 people).
read, experience
We can usually estimate or measure the error associated with a measurement though uncertainty can be based on how well we can ____ an instrument or our ____ with a particular method.
random, systematic
We discuss the propagation of ____ error since our goal is to eliminate ____ error.
even
When a number is exactly halfway, round to the nearest ___ digit (this avoids systematically increasing or decreasing results through successive round-off errors since half the round-offs will be up and half down).
exponent
When adding or subtracting numbers in scientific notation, make sure that all the numbers are first expressed with the same _____.
y, x
When x=e^y, ___ is the natural logarithm of __.
decimal places
With addition and subtraction, round the answer to the fewest ___ _____.
absolute, relative
With addition and subtraction, the uncertainty in the answer is obtained from the ____ uncertainties of the individual terms (_____ uncertainty can be found at the end of the calculation).
relative uncertainty
With logarithms, the absolute uncertainty in y is proportional to the ___ ____ in x.
percent relative uncertainty, absolute
With multiplication and division, first convert all the uncertainties into ___ ____ _____ (_____ uncertainty can be found at the end of the calculation).
percent relative uncertainty
With powers, use __ ___ ___.
middle, end, right
Zeroes are significant when they occur in the ___ of a number or at the ___ of a number on the ___-hand side of the decimal point.
certified reference materials
__ ___ ____ are used to test the accuracy of your analytical procedures, and the quantity of analyte in a reference material is certified with painstaking care to lie within a stated range.
absolute uncertainty
___ _____ expresses the margin of uncertainty associated with a measurement.
relative uncertainty
____ ____ compares the size of the absolute uncertainty with the size of its associated measurement.
systematic, determinate
____ error, or _____ error, arises from a flaw in equipment or the design of an experiment
every, experimental error
____ measurement has some uncertainty, which is called ___ __.
random, indeterminant
_____, or ______, error, arises from uncontrolled and maybe uncontrollable variables in the measurement.
0.001
antilogarithm of -3
100
antilogarithm of 2
e
base of the natural logarithm
-3
base ten logarithm of 0.001
2
base ten logarithm of 100
characteristic, mantissa
components of a logarithm
significant figures
minimum number of digits required to express a value in scientific notation without loss of precision
accuracy
nearness to the "truth"
precision
reproducibility
positive, negative
systematic error may always be ___ in some region sand always ___ in others.
-4, 0.470
-4.470- What is the characteristic and mantissa?
systematic
A pH meter that has been standardized incorrectly produces a ____ error.
more
A smaller scale means ____ uncertainty in the last digit.
1, 2
In multiplication and division, keep an extra digit when the answer lies between _ and _ (so that the uncertainty is not too large).
significant figures
In multiplication and division, the answer is limited to the number of digits in the number with the fewest ___ ____.
knowns, blank, methods, round robin
Detect systematic error by analyzing a ___ sample, analyzing ____ samples, using different analytical ____ to measure the same quantity, or a ___ ____ experiment.
random
Different people reading a scale or one person reading a scale multiple times is an example of ____ error.
percent
Do not use ____ relative uncertainty with logs and antilogs since one side of the equation has relative uncertainty and the other has absolute uncertainty.
random
Electrical noise in an instrument, with positive and negative fluctuations occurring with approximately equal frequency is ____ error.
tenth
Estimate all readings to the nearest ____ of the distance between scale divisions.
confidence, proof
Good agreement among several methods affords us ____ but never ____ that results are accurate.
n=10^a
If logn=a, then
n, a
If logn=a, then _ is the antilogarithm of _.
n, a
If n=10^a, then _ is the antilogarithm of _.
logn=a
If n=10^a, then ____
standard deviation, mean, confidence interval
If possible, uncertainty will be expressed as ___ ___ of the ___ or a ___ ___.
accurate
If the results of measuring the same quantity by different methods agree with one another, then we become confident that the results are ____, which means they are near the "true" value.
4th
If the uncertainty is +/- 0.0002, the answer should go to the ___ decimal place regardless of significant figures.
2, 3, 4
In 0.234, _ and _ are certain but _ is an estimate.
mantissa
decimal part of a logarithm
characteristic
integer part of a logarithm
4
log(5.403 x 10^-8) has how many digits in the mantissa?