TOPIC #1:
ORIENTATION; BASIC UNITS AND CACLULATIONS
The
purpose of this first lab session
is to acquaint you with the overall general idea of laboratory science, and to get you
started on some
basic calculations.
We will discuss the general idea of this portion of Biochem 107, and get familiar
with the various types of units used to measure length, mass, and volume, and how to do some
basic conversions.
Be sure you bring your calculator to each lab session, including this one.
Objectives:
By the end of today's lab session, you should:
1.
Know and understand the metric units for length, mass, and volume, and be familiar with the Celsius
temperature scale.
2.
Be able to make metric/English conversions (you don’t need to know conversion factors).
3.
Understand and be able to manipulate the prefixes of the basic units of measure.
4.
Be able to convert numbers to scientific notation and vice versa.
5.
Understand the terms error (random vs systematic), accuracy, precision, & uncertainty.
6.
At least be beginning to enjoy the time you spend in Biochem 107L.
A.
UNITS OF MEASUREMENT
Common units of metric system measurement are given below, along with their English equivalents and conversion
factors (
don’t memorize the conversion factors!
).
Measurement
Metric
English
Conversion
length
meter (m)
inch (in)
1 in = 2.54 cm
mass
gram (g)
pound (lb)
1 lb = 454 g
ounce (oz)
1 oz = 28.35 g
volume
liter (L)
quart (qt)
1 qt = 0.946 L
The entire scientific community utilizes the metric system, and we will use it exclusively in this course.
You will also
use it routinely in your future career, so you need to have a good working knowledge.
You should also be able to
convert units between the metric and English systems, and convert units within the metric system.
Be sure you
understand the material in Section 1.3 – Measurement in Chemistry (pp. 11-16) of your textbook, in particular the
portions on conversions.
We will help you with this during this lab exercise if you need.
The units of the metric system will be easier to remember and understand if you can relate them to the everyday world
around you.
For instance, keep in mind that
one liter is about one quart
,
one kilogram weighs about 2 pounds
,
100 g is
about 4 oz
(one-fourth of a pound; a stick of butter), etc.
See
the diagrams below
Length
Comparison of met ric and English
unit s of lengt h
1 cm x 1 cm x 1 cm
=
1 cm
3
1 cc = 1 mL
1, 000 cm
= 1, 000 mL = 1 lit er (L)
Volume
and English
unit s of volume
Mass
Compar ison of met ric and English
unit s of volume
1 kg = 1, 000 g
≈
2. 20 lbs
Temperature
Compar ison of t emperat ure scales
Kelvin
Celsius
Fahrenheit
(K)
(
°
C)
(
°
F)