Study Guide for Chapters 1 and 2
Section 1.1 Units of measurement.
When you finish this section, you will be able to:
List the fundamental Metric and SI units of measurement
List the important SI prefixes.
It is important to develop “a feel” for units in the Metric and SI systems. For example
measurement in meters is fine if you are measuring how tall you are. On the other hand if you
are measuring the distance between Los Angeles and San Diego, you should use kilometers, or
km. Kilo is the prefix meaning 1000. Thus 1km = 1000 m. When you go to the grocery store in
France to buy milk, the volume is listed as liter (Metric unit) not in cubic meter (SI unit for
volume) which is too big. 1m3 = 1000 liters. You should know the units listed in table 1.1 , page
17 of Timberlake’s textbook.
Section 1.2 Scientific Notation
You should learn to express any decimal number in exponential notation: c x 10 e . C is the
coefficient. In scientific notation c is between 1 and 10. e is the exponent. 10e is 10 raised to the
e power. When e is larger than 0, 10e is larger than 1; when e is smaller than 0, 10 e is smaller
than 1. Remember that 100 = 1
You should look at some examples in table 1.2, page 19 of textbook
1-3 Measured Numbers and Significant Figures
When you finish this section, you should be able to define accuracy and precision.
When you measure a quantity many times, you have to ask yourself two questions:
1.
Is the average close to the accepted value? If it is, then the result is accurate.
2.
How close your values are to one another? If there are close then the result is precise.
When you finish this section you should be able to determine the number of significant figures.
When you report a measured value, it is assumed that all the figures are correct except for the
last one, where there is an uncertainty of ±1. The number of significant figures is the number of
digits that are known accurately plus the uncertain digit. The rules for counting significant
figures are given in the handout page 2, chapter 1.
When you finish this section you should be able to determine when you have an exact number.
Counting numbers are exact. Numbers fixed by definition are exact.
1-4 Significant Figures in Calculation
There is uncertainty in all measured values. Performing mathematical operations with measured
values will give result with certain uncertainty. When you use calculator to do calculations, you
need to round off the result to give the answer with the correct number of significant figures.
The rules for round off a sum or difference are different from the rules for multiplication and
division.
You need to learn the rules presented in paragraph 1-4 of the handout. Recall that you
round off at the very end of the problem and always make sure that your answer is
reasonable.
1-5 Prefixes and Equalities
You should try to memorize the prefixes, at least the most common ones as kilo, centi,
milli.
1-6 Writing Conversion Factors
When you finish this section, you should be able to:
1.
Concert between English and metric unit
2.
Convert values from one prefix to another.
You should also learn the dimensional analysis method, which involves using conversion
factors to cancel units until you have the proper unit at the end. When you are setting
up problems using dimensional analysis, you are more concerned with units that with
numbers. Always double check that your units cancel properly. If they do, your
numerical answer is probably correct. Dimensional analysis often involves
interconversion between prefixes of the same unit. Carelessly inverting prefix
conversion (such as incorrectly stating that 1 cm = 100 m; 1m = 1000 km) is among the
major sources of errors. Remember that:
Result of a measurement = number x unit
If the unit is small (cm for example) the number is large; if the unit is large (km for
example) the number is small.
You do not have to memorize the relationship between the Metric and the English
systems.
1-7 Density.
When you finish this section, you will know the definition of density
Density = mass/ volume
There are three quantities: density, mass and volume. If you are given two of them, you
can use the above equation to calculate the unknown. Remember to use the proper
units. The unit for density is a derived unit, most often expressed as g/mL.
The specific gravity of a liquid is the ratio of its density over the density of water. Since the
density of water in SI units is 1.00 g/cm3, the specific gravity for a liquid is the same as its
density without units.
2.1 Energy.
When you finish this section, you should be able to:
1. Define energy of a system as its capacity to perform work.
2. Know the conservation of energy.
3. Know that a system can exchange its energy with its surrounding under two forms: heat and
work
4. Know the unit for energy Joule and calorie
2.2 Energy and Nutrition
You should know that in the field of nutrition, the Calorie, Cal (with an uppercase C), means
1000 cal
1 Cal = 1000 cal = 1 kcal
2.3 Temperature Conversion
When you finish this section you should be able to state the followings regarding the three
temperature scales :
1. The unit for each one ( 0C ,0F, K )
2. The freezing point and boiling point of water in each scale
3. how to convert among them
2.4 Specific Heat
You should know the definition of specific heat as the amount of heat needed to raise the
temperature of 1 gram of a substance by 1 0C
2.5 State of Matter: Gas, Liquid, Solid
You should be able to define the three common states of matter (gas, liquid, solid) and their
properties.
2.6 Change of states
You should be able to describe the changes of states: melting, solidification (freezing),
sublimation, boiling (evaporation), condensation.
Knowing to perform calculations using specific heat, heat of fusion, heat of vaporization is not
required but recommended if you want to get extra credits for the quiz 1.