CHEM101 Study Guide Test 2 (2014-15)
Chapter 5 - Molecules and Compounds
 Using the octet rule, predict the ion charge of simple ions for the representative elements
o Know the octet rule (elements (except He, H) try to get valence of 8; H and He need 2)
o Know charge of ions that Group 1,2,14,15,16,17,(18) elements are capable of making
 Using charge balance, write the correct formula for an ionic compound from its name
o Know that ionic compounds don’t exist in individual units, but we refer to the smallest
theoretical piece as a formula unit
o Know that compounds can be either covalent or ionic; be able to determine type from
formula or name
o Know the parts of a chemical formula (element symbol, subscript, groups)
o Know how to lookup charge of ions that Group 3-13 elements are capable of making
o Know how to lookup formula, charge and name of polyatomic ions
 Given the formula of an ionic compound (including ones with polyatomic ions and multivalent
ions), write its correct name
o Know how to determine the charges of ions in a chemical formula using charge balance
o Know how to lookup the formula, charge and name of polyatomic ions
 Given the formula of an covalent compound, write its correct name; given the name of a
covalent compound, write its formula
o Know the seven elements that exist naturally as diatomic elements
o Know that a molecule is an individual unit of a molecular compound
o Know the greek prefixes for 1-10
Chapter 6 - Chemical Composition
 Use Avogadro’s number to convert between moles and particles
o Particles can be either atoms, molecules, or formula units
o Know the definitions of mole, Avogadro’s number
A mole is a set of 6.02 x 1023 items (Avogadro’s number) that is handy to use in chemistry because a
mole of particles has the same mass in grams as one particle has in amu’s.
 Use subscripts to convert between # of compounds and elements within them
o Convert moles of a compound to moles of an element
Ex. 3 mole CH4 has 3x4=12 moles H
 Calculate molar mass of elements and compounds using a periodic table
 Use molar mass to convert between mass and moles
o Convert grams to molesfor an element and for a compound
o Perform multiple step conversions (g of a compound to # of atoms of an element in it)
 Calculate the empirical formula of a compound given % composition by mass
o Know the definitions of % composition, empirical formula, molecular formula
% composition is the mass percentage of an element within a compound; Empirical formula is the
smallest whole number ratio of atoms of elements in a compound, written as a chemical formula.
Molecular formula states the exact number of atoms of elements in a compound (must be whole
numbers), written as a chemical formula.
 Calculate % composition by mass given the empirical formula of a compound
HW
1, 2
7, 8
6
12
9, 10
13, 14
5
1
3, 11
4, 5
6, 7,
13
2,3, 8, 9, 11
12
14
16
15
Chapter 7 - Chemical Reactions
 Write a chemical reaction equation given a written description of the chemical change
o Know the definitions of: reactant, product, reaction, yields
 Balance a chemical reaction [change coefficients, NOT subscripts]
o Know the difference between a subscript and coefficient
 Identify type of chemical reaction from full reaction or from reactants only
o combination, decomposition, single displacement, double displacement, combustion
 Write molecular, ionic and net ionic equations for a precipitation reaction
 Define solubility and identify an insoluble salt
 Know select combination reactions:
o metal + O2  metal oxide
o metal + nonmetal  binary salt (ionic compound of the ions made from each)
o metal oxide + H2O  metal hydroxide
o metal chloride + O2  metal chlorate
 Know select decomposition reactions:
o metal oxide  metal + O2
o binary salt  metal + nonmetal
o metal hydroxide  metal oxide + H2O
o metal chlorate  metal chloride + O2
o metal carbonates  metal oxide + CO2
 Predict products of a reaction (from just reactants)
o for select combination reactions
o for select decomposition reactions
o for any single displacement reaction (and if it will occur based on activity series)
o for any double displacement reaction
1, 6, 7,16
2-5, 12,
13, 16
10, 24-5
18, 21
17
19, 20
12,13,14,15
Chapter 8 - Quantities in Chemical Reactions
 definitions: stoichiometric ratio, limiting reactant, mass conservation, percent yield

be able to write a stoichiometric ratio

Mole-Mole conversions
o convert moles of one compound to moles of another in the same reaction
Mole-Mass conversions
o convert moles of one compound to mass of another in the same reaction
Mass-Mass conversions
o convert mass of one compound to mass of another in the same reaction
Determine limiting reactant from amounts of two or more reactants
Calculate theoretical yield from limiting reactant
Calculate % yield from moles of reactant and actual yield
o use moles reactant to find theoretical yield
Identify exothermic and endothermic reactions
o Understand that during a chemical reaction, the system may absorb/release a fixed
amount of heat per amount of reactant (called Hrxn) because the potential energy of the
system is changing. Identify whether a reaction is exo- or endothermic by its Hrxn)
o Exothermic reactions give off heat and have a negative Hrxn; Endothermic reactions
absorb heat and have a positive Hrxn)
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1, 2
4, 5, 6
7, 8, 9,
10
17
3, 18, 19
21, 22,
23, 24
25-28