1. Definitions – The language of chemistry
a. Matter – Anything that has mass and volume – chemical compounds, planets,
b. Composition – The types and amounts of simpler substances (atoms – elements)
that make up a sample of matter
c. Properties – the characteristics that give each substance a unique identity
i. Physical Changes:
1. Chemical bonds remain intact
2. boil, evaporate, sublimation
ii. Gases are compressible fluids. Widely separated
iii. Liquids are relatively incompressible fluids
iv. Solids are nearly incompressible and rigid; molecules or ions are in close
contact/immobile, and the only movement is vibration.
d. Element – consists of only one type of atom, and cannot be broken down into
simpler substances by physical or chemical means. Simplest type of substance
with unique physical and chemical properties.
e. Molecule – Structure consists of two or more atoms that are chemically bound
together, behaves as independent unit.
f. Compound – Substance composed of two or more elements which are chemically
2. Periodic Table
a. Since many metals exhibit similar types of reactions, it is a property a chemist
immediately thinks about when he or she encounters the symbol for the element.
b. Metalloids divide metallic elements on left from nonmetals from the right (except
hydrogen) Therefore memorize the metalloids, so you can classify the metals as
those to the left of the metalloids, and the nonmetals as those to the right (except
a. Group of two or more substances that are physically intermingled (mud, skim
i. Asolution is a special type of homogenous mixture, such as sea water,
brass, where everything is in the same phase. Solutions in water solvent
are very common and called aqueous solutions. 1. Solvent is the term for the majority liquid component and solute is
used for the minor component that is dissolved.
ii. Heterogeneous Mixtures have one or more visible boundaries
iii. Homogeneous Mixtures or Solutions have no visible boundaries because
the components are mixed as individual atoms, ions, and molecules, such
as aqueous solutions. May exist in all three physical states.
b. Elements that are diatomic in their natural state:
4. Law of Mass Conservation
a. Total mass of substances does not change during a chemical reaction.
5. Law of Definite (Constant) Composition
a. No matter the source, a particular pure compound is composed of the same
elements in the same parts (fractions) by mass.
6. Calculating the Mass of an Element in a Compound
a. Problem: Quartz or silica is the principal component in sand and has the formula
SiO2.Analysis shows that 60.08g of quartz contains 28.05 g of the element
silicon, with oxygen as the only other element. How many grams of silicon, which
is used to make computer chips, can be obtained from 150kg of silica?
i. The mass fraction of silicon (Si) in silica
Quiz every 2 – 3 Weeks, 4 – 5 questions
4 quizzes, but lowest one dropped
a. What is a significant figure?
i. Defines how precise a measurement is
ii. Non-zero terms are always significant figures:
1. 1.61 = 3 significant figures
2. 1.21 = 3 significant figures
3. 323.4 = 4 significant figures
iii. Any “zero” terms between any non-zero terms are significant as well:
1. 34,001 = 5 significant figures
iv. “Trailing” zeros are always insignificant figures, unless bounded by
decimals or bars (the number in the bar also counts), or are after decimal
1. 0.0034 has two significant figures, they simply define the
magnitude of the number.
2. 0.00340 has three significant figures, because the trailing zero
counts. The number with the fewest significant figures limits the
number of significant figures in the answer.
1. 1. All non-zero digits are considered significant.
a. For example, 234.56 has five significant figures: 2, 3, 4, 5,
2. Zeros appearing anywhere between two non-zero digits are
a. For example, 201.34 has five significant figures: 2, 0, 1, 3,
3. Leading zeros are not significant.
a. For example, 0.00023 has two significant figures: 2 and 3. 4. Trailing zeros in a number showing a decimal point are significant.
a. For example, 23.4500 has six significant figures: 2, 3, 4, 5,
0, and 0.
5. If the left-most digit dropped is the number five or greater (5
through 9), round up.
1. The number with the fewest significa