Chemistry – Study Guide for 2nd Trimester Exam (Chapters 9 – 11.1)
Chapter 9 – Chemical Names and Formulas
9.1 – Naming Ions
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When the metals in Groups 1A, 2A, and 3A lose electrons, they form cations with
positive charges equal to their group number.
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The charge of any ion of a Group A nonmetal is determined by subtracting 8 from the
group number.
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The charges of cations of many transition metal ions must be determined from the
number of electrons lost. When a cation can have more than one ionic charge, a Roman
numeral is used in the name to indicate the charge.
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The names of most polyatomic anions end in –ite or –ate.
9.2 – Naming and Writing Formulas for Ionic Compounds
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The name of a binary ionic compound is the cation name followed by the anion name.
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To write the formula for a binary ionic compound, write the symbol for the cation and
then the anion. Then balance the charges.
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To write formulas for compounds containing polyatomic ions, write the symbol for the
metal ion followed by the formula for the polyatomic ion and balance the charges.
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To name a compound containing a polyatomic ion, state the cation first and then the
anion.
9.3 – Naming and Writing Formulas for Molecular Compounds

Prefixes show how many atoms of each element are present in a molecule of a binary
compound.
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To write the formula for a binary molecular compound, write the symbols for the
elements and use the prefixes to determine the subscripts. Omit mono- for a single atom.
9.4 – Naming and Writing Formulas for Acids and Bases

An acid is a combination of a monatomic or polyatomic anion with sufficient hydrogen
atoms to make the compound electrically neutral. Acids are names as shown in Table 9.5.

A base is a combination of a cation with as many hydroxide ions as are needed to make
the compound electrically neutral. Bases are named in the same way as other ionic
compounds.
Chemistry – Study Guide for 2nd Trimester Exam (Chapters 9 – 11.1)
9.5 – The Laws Governing Formulas and Names

The ways that compounds form are summed up in two laws: the law of definite
proportions and the law of multiple proportions.

To name a compound or write its formula, follow the flowcharts in Figures 9.20 and 9.22
to the correct name or formula.
Chapter 9 Vocabulary:
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Acid
Base
Binary Compound
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Law of Definite
Proportions
Law of Multiple
Proportions
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Monatomic Ion
Polyatomic Ion
Chapter 10 – Chemical Quantities
10.1 – The Mole: A Measurement of Matter

Three methods for measuring the amount of a substance are by count, by mass, and by
volume.

A mole of any substance always contains Avogadro’s number of representative particles,
or 6.02 x 1023 representative particles.

The atomic mass of an element expressed in grams is the mass of a mole of the element.

To calculate the molar mass of a compound, find the number of grams of each element
contained in one mole of the compound. Then add the masses of the elements in the
compound.
10.2 – Mole-Mass and Mole-Volume Relationships

The molar mass of an element or compound is the conversion factor for converting
between the mass and the number of moles of a substance.

One mole of any gas occupies a volume of 22.4L at standard temperature and pressure.
One mole of any substance contains Avogadro’s number of particles, so 22.4L of any gas
at STP contains 6.02 x 1023 representative particles of that gas.
10.3 – Percent Composition and Chemical Formulas

To determine the percent by mass of any element in a given compound, divide the
element’s mass by the mass of the compound and multiply by 100%
Chemistry – Study Guide for 2nd Trimester Exam (Chapters 9 – 11.1)

An empirical formula of a compound is the simplest whole-number ratio of atoms of the
elements in the compound.

The molecular formula of a compound is either the same as its experimentally determined
empirical formula, or it is a simple whole-number multiple of it.
Chapter 10 Vocabulary:
 Avogadro’s Hypothesis
 Avogadro’s Number
 Empirical Formula
 Molar Mass
 Mole
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Percent Composition
Representative Particle
Standard Temperature and Pressure
(STP)
Key Equations:
1mole
6.02 x1023
6.02 x1023
Representative Particles = moles x
1mole
mass ( grams )
mass ( grams )  number of moles x
1mole
1mole
Moles  mass(grams) x
mass ( grams )
grams grams 22.4 L

x
mole
Liter 1mole
22.4 L
Volume of Gas = mole of gas x
1mole
mass of element
% Mass of Element =
x100%
mass of compound
Moles  Representative Particles x
Chapter 11 – Chemical Reactions
11.1 – Describing Chemical Reactions

To write a word equation, write the names of the reactants to the left of the arrow
separated by plus signs; write the names of the products to the right of the arrow, also
separated by plus signs.

To write a skeleton equation, write the formulas for the reactants to the left of the yields
sign and the formulas for the products to the right.

After writing the skeleton equation, use coefficients to balance the equation so that is
obeys the law of conservation of mass.
Chemistry – Study Guide for 2nd Trimester Exam (Chapters 9 – 11.1)
Chapter 11 Vocabulary:
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Activity Series
Balanced Equation
Catalyst
Chemical Equation
Coefficients
Combination Reaction
Combustion Reaction
Complete Ionic Equation
Decomposition Reaction
Double-Replacement Reaction
Net Ionic Equation
Single-Replacement Reaction
Skeleton Equation
Spectator Ion