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?