SPECIFIC VOLUME  and  SIG FIGS

What is SPECIFIC VOLUME
"Specific", when applied as a modifier to a extensive physical property, generally refers to the value of this property for one gram of material.

Specific Volume is the volume of one gram of material. It has the units of volume per gram. In metric units this is usually....... mL/g or cc/g .

Note: Specific Volume is the reciprocal of Density....... Sp.Vol. = 1/D

The importance of being a..... SIG FIG
...

Sig Figs are of critical importance in the LABORATORY.
They have a two fold purpose:

A. They indicate the accuracy of a measurement.

B. They indicate the accuracy of a calculated value derived from these measurements.

REMEMBER
Errors made in the measurement are propagated through the calculations.
In a measurement...
A) Your ability to replicate a measurement determines the number of sig figs.
Given the following measurements of atmospheric pressure (mm Hg or torr) by a computer interfaced with a pressure sensor taken over a period of several seconds:

762.1379, 762.2195, 762.1155, 762.0179, 762,0888

It is clear that the initial uncertainty starts at the first decimal place but becomes random at the second decimal place and beyond.
These series of readings should best be recorded as......... 762.1 mm Hg.
B) In reading a graduated scale, read between the lines.
A buret graduated to 0.1 mL should be read to .01 mL.
A spectrometer graduated to 1% T should be read to 0.1% T.
In a calculation...

A) For numbers added or subtracted, the absolute error is propagated

B) For numbers multiplied or divided, the per cent error is propagated

C) Combination of errors in two or more numbers can, relative to the errors of each individual number, increase or decrease the error in the final value

©  RW Kluiber 1/15/2001