Unit 1: Basic Concepts of Chemistry
Overview:
 Chemistry and its methods – laws, hypotheses and theories - goals of science and the ethical
and moral dimension
 Classifying matter
 Elements and molecules
 Compounds and molecules
 Physical properties
 Physical and chemical change
 The tools of quantitative chemistry

Learning Outcomes:
 Understanding differences between hypotheses, laws and theories.
 Understanding connection between the kinetic-molecular theory and states of matter
 Understanding difference between pure substances and mixtures and the difference between
homogeneous and heterogeneous mixtures
 Understanding the importance of and differences between macroscopic and microscopic
(atomic) descriptions of matter
 Identifying names and symbols of elements and correct usage of the terms atom, element,
molecule and compound
 Knowing commonly used physical properties and understanding difference between intensive
and extensive properties
 Understanding the difference between physical and chemical change
 The tools of quantitative chemistry
o Understanding the International System of Units
 Base quantities and the SI base units, their names and abbreviations
 Scientific prefixes
o Understanding difference between precision and accuracy
o Understanding experimental error and standard deviation
o Mathematics of chemistry
 Understanding exponential notation
 IMPORTANT – entering numbers into calculator using exponential
notation
 Understanding correct application of significant figures
 Using dimensional analysis to solve problems
 Graphing and correct labeling of axes
 Application of problem solving strategies
Readings: Sections 1.1 – 1.5 and The Tools of Quantitative Chemistry
Assignment: From Chapter 1: # 6, 8, 10
Review: # 6, 14, 18, 24, 30, 44, 46, 58
Introduction:
This unit serves as an introduction to the study of chemistry. In this section, you will
notice highlighted words such as substance, element and mixture. These words have specific
meanings, and understanding them now will make reading in subsequent chapters much easier.
Atoms and molecules as well as solids, liquids and gases are introduced here. As you read
through this section try to think of how atoms and molecules appear in the three states of matter,
and think about what kinds of movement they may exhibit in these states of matter. This helps
you link the microscopic and macroscopic worlds of chemistry.
We begin by learning about the scientific method. This provides us with guidelines to
design experiments, draw reasonable conclusions from the data and develop an understanding of
the science behind the experiment. Often, experiments are repeated and revised many times
before we have a satisfactory understanding of the chemical or physical principles involved.
In our experiments, substances can exist in three states: solid, liquid and gas. By
changing the temperature, one state can be converted into another. Depending on the direction
of the change, energy is released or consumed by these changes of state. Later in the course, we
will consider changes of state in more detail, but the starting point for such discussions begins
here.
Some familiar terms arise in this chapter such as atom, molecule, element and compound.
After your reading, ask yourself, "What is the difference between an atom and a molecule?" and
"What is the difference between an element and a compound?". Sometimes, the meaning of a
word, such as oxygen, is ambiguous. Consider the statement, "Water contains oxygen." Does
the oxygen in water appear as an atom, element, compound or molecule?
The distinction between physical and chemical properties is easier to determine. With the
help of your textbook, create a list of physical properties and of chemical properties. No doubt,
your collection of properties includes melting point and, perhaps, flammability. Now, choose an
element such as hydrogen and attempt to write an equation describing the melting of solid
hydrogen and the combustion of hydrogen. Looking at these two equations, how would you
distinguish a chemical change from a physical change? Sometimes, classifying changes as
being chemical or physical is easy, and other times it is not.
Some aspects of chemistry are qualitative, but we often quantify things in chemistry.
Probably the best thing you can do at this point is to become familiar with the details of the
metric system. Not only does the metric system allow us to measure things using a standard
system of measurement, but since the base units are easily related to derived units, metric
measurements greatly simplify our calculations. All calculations in science can be done with the
metric system, but often scientists need to work with data in non-metric units such as pounds per
cubic foot and report answers in units other than those used in the metric system, such as tons per
acre. Because of this, it is essential that you have the skills to convert between various units
when conversion factors are provided.
Data can be characterized according to its accuracy or precision. These are two
completely independent ways of describing the data. To quantitatively describe accuracy, we
may use a measure such as relative error. To describe precision, we may calculate the standard
deviation. If the data is important, it is worth quantifying its accuracy and precision. This leads
to a discussion of significant figures. Students often ask the very valid question, "How many
significant figures should I report?". Depending on the problem, the answer to this question can
not be stated with certainty. While significant figures are very important in science, usually
more sophisticated statistical methods are used to determine which digits of a number are
significant, and which are not.
Concluding Remarks:
Some or most of the material in this first chapter may be review from high school
courses. You also may be tempted to quickly pass over the section covering the metric system
and describing data in terms of accuracy and precision since 'this is not chemistry', but resist this
temptation. The skills being developed through this section are skills that all scientists are
expected to possess. Later in this course, you will be solving problems that will require mastery
of these skills, so build that solid foundation now.