Studied by 2 people6- Properties of Covalent Compounds
sharing of e-
occurs between elements that are similar
ex) between two nonmetals or metalloids
never conductive as a solid or as a solution in water
do not dissolve in water
exception: sugar
shorter bond = higher force of attraction, higher bond E
longer bond = lower force of attraction, lower bond E
6- Properties of Ionic Compounds
transferring of e-
nonmetal takes e- from metal
forms crystal lattice
brittle
high melting/boiling point
very strong bond
when solid:
ions in fixed position
nonconductive
when dissolved in water:
ions move freely
conductive
6- Properties of Metallic Bonding
forms crystal lattice
nucleus of a metal
delocalized e- (sea of e-)
free to move about the entire crystal lattice
orbitals overlap
malleable and ductile
high melting/boiling point and heat of evaporation
strong bonds
conductive as solid
insoluble
luster
6- Lewis Structures
ionic compound- composed of cations (metals) and anions (nonmetals)
Lewis Structures must be electrically neutral
6- Polarity
nonpolar molecules:
dipoles cancel
ends have same partial charges
polar molecules:
dipoles do not cancel
ends have opposite partial charges
6- Shapes of Molecules (molecular geometry)
linear
bent
trigonal planar
trigonal pyramidal
Tetrahedral
6- Intermolecular Forces
London dispersion forces (LDF)
all molecules have LDF
weakest IMF
dipole-dipole force
any polar molecule that doesn’t have H bonding has this
hydrogen bonding
must be polar
must have hydrogen bonded to high energy anion (N, O, or F)
strongest IMF
7- Naming and Writing Chemical Formulas
monatomic ions
element symbol + charge
ex) Na^+
ex) O^2-
ex) Zn(II) <- like this for all transition metals
binary ionic compounds
cation + anion name with -ide
ex) Aluminum Oxide - Al_2 O_3
ex) Silver Chloride - AgCl
no number prefixes, since cation charge determines number of anions and vice-versa
binary molecular compounds
first element in formula + second element in formula with -ide
inorganic prefixes
“mono” is understood for first element, but necessary for second
ex) dichlorine monoiodide
ionic compounds with polyatomic ions
cation name + polyatomic ion name (anion)
7- Mass, Percent Composition, and Molar Mass Conversions
percent composition
part/whole
ex) percent of water in a hydrate:
molar mass H2O/molar mass of entire formula
formula mass = molar mass
Avogadro’s number = 6.022*10^23
molecules to moles uses Avogadro’s number
6.022*10^23 molecules/1 mol
formula units to moles uses Avogadro's number
6.022*10^23 formula units/1 mol
7- Empirical and Molecular Formulas
empirical formula is the smallest whole number ratio of the subscripts in a compound
molecular formula is the actual formula of the compound
x(empirical formula) = molecular formula
x = molecular formula molar mass/empirical formula molar mass
to find empirical formula:
take grams of all elements in compound and convert to moles (if given percentages, just pretend they are grams, it doesn’t matter)
divide all by the smallest amount of moles
if there is a _.5, multiply all by 2
use these numbers as subscripts for the formula (1s are implied)
8- Evidence of a chemical change
color change
gas production
change in state of matter (formation of a precipitate)
energy production/consumption
8- Chemical Equations
reactants on left, products on right
balanced when the amount of each element is equal on both sides
must contain states of matter symbols
coefficients- the only things that change
balance atoms that appear only once on each side of the equation first
balance polyatomic ions as single units
balance H and O last
if an atom can be balanced with a coefficient of 1/2, use it, then multiply all coefficients by 2 at the end
8- Predicting Products
synthesis
to or more substances combine to make a compound
1 product
A + X → AX
decomposition
a single compound undergoes a reaction that produces two or more simpler substances
1 reactant
AX → A + X
single displacement
one element replaces a similar element in a compound
USES ACTIVITY SERIES
one element can only replace a similar element if that similar element is lower on the activity series (back of periodic table)
metal replacement
A + BX → AX +B
halogen replacement
Y +BX → X + BY
double displacement
ions of two compounds trade places in an aqueous solution to form new compounds
AX + BY → BX + AY
combustion
a substance combines with oxygen, releasing a large amount of energy in the form of heat or light
CxHy (g) + O2 (g) → CO2 (g) + H2O (g) +Energy
only contains elements hydrogen, oxygen, and carbon
remember to balance!!!!!!!!
9- Yields
actual yield- the amount of product, affected by human/equipment error attained from a reaction in real-life experiment
theoretical yield- the supposed amount of product attained from a reaction, based purely on its mol ratio with a known quantity of another reactant or product
percent yield- way to exemplify the accuracy of an actual yield by comparing it to the theoretical yield
percent yield= (actual/theoretical)*100
9- Limiting Reactants
coefficients indicate mol ratio
limiting reactant- the reactant whose difference in a have/need table has a negative sign
know how to apply have/need table
excess reactant- the reactant whose difference in a have/need table has a negative sign
know how to apply have/need table
10.5, 12, and 13- Solute-Solvent Combinations
solutions
homogenous mixture
smallest particle size
0.01-1 nm
cannot be separated through filtration
particles aren’t large enough to settle out
colloids
appears to be one phase, but is actually heterogenous on the particle level
intermediate particle size
1-1000 nm
cannot be filtered or settled
some separation occurs if left to settle long enough
exhibits tyndall effect
particles large enough to scatter light (foam, fog, gel, etc.)
suspensions
visibly heterogenous
ex) oil and water mixture
can be filtered
settles unless consistently agitated
largest particle size
1000 nm or greater
10.5, 12, and 13- Rate of Dissolving
rate of dissolving- how much solute dissolves in solvent over time
factors that effect ROD:
^temp. = ^ROD
^kinetic energy (particle velocity) = more particle collisions
^surface area = ^ROD
^contact = more particle collisions
agitation = ^ROD
^contact = more particle collisions
solubility curve- graph to model rate of dissolving
y-axis: amount of solute
x-axis: time
10.5, 12, and 13- Solubility
the amount of a substance, in grams, required to form a saturated solution with a specific amount of solvent
dependent on:
nature of solute and solvent
temp. of solvent
solubility equilibrium- solute is recrystallizing at the same rate that the crystal is dissolving
10.5, 12, and 13- Electrolytes/Nonelectrolytes
electrolytes- when dissolved in water, the resulting solution conducts electricity
ionic compounds
acids
bases
nonelectrolytes- when dissolved in water, the resulting solution is nonconductive
molecular compounds
10.5, 12, and 13- Common Solute-Solvent Combinations
gas-gas
gas-liquid
liquid-liquid
liquid-solid
solid-liquid
solid-solid
10.5, 12, and 13- Miscibility
like dissolves like
polar dissolves in polar
nonpolar dissolves in nonpolar
ONLY APPLICABLE WITH LIQUIDS
10.5, 12, and 13- The Dissolving Process
dissociation
neg. end of water molecule attracted to cation, pos. end of water molecule attracted to anion
pulls apart molecule
hydration
water molecules surround anions and cations, oxygen faces cations and hydrogen faces anions
10.5, 12, and 13- Enthalpy of Solution
enthalpy of solution- the net amount of E absorbed when a specific amount of a solute dissolves
exothermic
neg. value
the E of separation of solute and solvent particles is less than the E produced
endothermic
pos. value
the E of separation of solute and solvent particles is greater than the E produced
10.5, 12, and 13- Solubility of Gases
Temperature
inversely proportional with solubility
Pressure
directly proportional with solubility (Henry’s Law)
10.5, 12, and 13- Density of Ice
0.92 g/ml
10.5, 12, and 13- Net Ionic Equation
total ionic equation, barring the spectator ions (ions that are identical on both sides of the equation)
10.5, 12, and 13- Molarity
unit of concentration
derived unit- mol/liter
expressed as “M”
17 and 18- Collision Theory
things that must be obtained in order for 2 reactants to make a product:
sufficient energy (different for every reaction)
correct orientation
17 and 18- Reaction Mechanisms
elementary steps- steps that make up a reaction mechanism
to add elementary steps together, intermediates must be eliminated
intermediates- substances that are produced in an early step and consumed in a later step
slowest step- rate determining step
even if a reaction is reversible, the reactants are on the left and the products are on the right
reversible reaction- a reaction that can be executed both ways, denoted by double-headed arrow
catalyst- consumed in early step and produced in later step
17 and 18- Energy Profile Diagrams
y-axis: energy (usually in KJ)
x-axis: course of reaction/reaction progress
Ea: reactant energy to activated complex
activated complex- sufficient energy, peak of graph
activated complex lowered by catalyst
Ea’: product energy to activated complex
delta E forward = E of products - E of reactants
when neg., reaction is exothermic (product E is less than reactant E)
when pos., reaction is endothermic (product E is greater than reactant E)
delta E reverse = same value as delta E forward, opposite sign
17 and 18- Equilibrium
chemical equilibrium- when the rate of the forward reaction is = to the rate of the reverse reaction
conc. of products and reactants is unchanged
it doesn’t matter if the amount of reactants and products are equal, only that the rate of exchange between them is equal
equilibrium constant:
ratio of products and reactants at a given temp. (since there is no conc. change at equilibrium)
this ratio is referred to as an equilibrium expression
does not include pure solids/liquids
uses molarity
denoted by K (no units, no sig figs)
small K values = reactants favored
large K values = products favored
K = 1 means reactants and products are equal
17 and 18- LeChatlier’s Principle
LeChatlier’s principle- if a system at equilibrium is subjected to stress, the equilibrium is shifted in the direction that tends to relieve its stress
stress: increase conc.-
increase reactant- forward, no effect on K
increase product- reverse, no effect on K
stress: decrease conc.-
decrease reactant- reverse, no effect on K
decrease product- forward, no effect on K
stress: change in temp.
increase temp.- reverse, K gets smaller
decrease temp.- forward, K gets bigger
stress: pressure-
increase pressure- forward, no effect on K
decrease pressure- reverse, no effect on K
14 and 15- Classifying Acids and Bases
arrhenius acid
produces a hydrogen ion: H+
OR
produces a hydronium ion: H3O+
these are the same thing but proving your claim with a dissociation equation will result in a H+ proof and an ionization equation will result in a H3O+ proof
arrhenius base
produces a OH- ion
if ionic: prove with dissociation equation
if molecular: prove with ionization equation
bronsted-lowry
acid: proton donor
base: proton acceptor
proton = H+ or H3O+ ion
acids and bases are reactants, never products
acids always have “H” as first listed element in formula
lewis
acid: electron pair acceptor; no unshared pairs on central atom
base: electron pair donor; unshared pairs on central atom
conjugate acid- the product that has received the proton
conjugate base- the product that has lost the proton
14 and 15- More Acid/Base Definitions
amphoteric- acts as an acid or a base, dictated by the substance it is reacting with
ex) H2O, also written as HOH (has both H+ and OH-)
nonmetal oxides will react with water to form an acid- can be shown through a simple synthesis equation
this is the process for acid rain
MEMORIZE: 3NO2 (g) + H2O (l) → 2HNO3 (aq) + NO (g)
only nonmetal oxide + water equation that won’t just synthesize
14 and 15- Titration
titration- the controlled addition and measurement of the amount of a solution of known conc. required to completely react with a measured amount of unknown conc.
equivalence point- moles acid = moles base
“end” of titration
reached when indicator turns color
14 and 15- Strong vs. Weak Acids and Bases
strong acids:
completely dissociate
strong electrolyte (lots of ions in solution)
identified by:
list of strong acids on periodic table (MEMORIZE!!!)
equation has single headed arrow (this is your proof)
weak acids:
slightly dissociate
weak electrolyte (few ions in solution)
identified by:
any acid not on strong acid list
equation has double headed arrow (this is your proof)
strong bases:
completely dissociate
strong electrolyte (lots of ions in solution)
identified by:
contains group 1/2 metal and OH- (this is your proof)
weak bases:
slightly dissociate
weak electrolyte (few ions in solution)
identified by:
contains metal not from group 1/2 and OH- (this is your proof)
14 and 15- Equivalence Point
strong acid and strong base-
equivalence point = pH 7
weak acid and strong base-
equivalence point > pH 7
strong acid and weak base-
equivalence point < pH 7
14 and 15- Toolbox Square
14 and 15- Titration Stoichiometry Sig Fig Rules
14 and 15- Weak Acid Stoichiometry
since weak acids do not completely dissociate, you can’t use a mole ratio
you must use a RICE table
remember: no pure liquids or solids in RICE tables!!!!!!
14 and 15- Endpoint
the pH indicator is the color that indicates complete titration
Note 
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