Exam W 10/28
Review T 10/27 1 pm SL 150
Happy Mole Day!
• Soluble = ability to dissolve in a liquid
• Insoluble = inability to dissolve in a liquid
• Not all Ionic Compounds are water soluble
• Not all molecular compounds are insoluble!
8 Simple Rules For Common
Song For Solubility!!
(Taken from Cornell University – Adapted by Daley – Sing to Rhythm of 99 Bottles)
Potassium, sodium, and ammonium salts,
Whatever they may be, Hydroxides of metals won't dissolve
Can always be depended on That is, all but three
For solubility. Potassium, sodium and ammonium
Asked about the nitrates or acetates Dissolve quite readily.
The answer is always clear,
They each and all are soluble, And then you must remember
Is all we want to hear. That you must not "forgit"
Calcium, barium, strontium
Most every chloride's soluble Dissolve a little bit.
At least we've always read
Save silver, mercurous mercury The carbonates are insoluble,
And (slightly) chloride of lead. It's lucky that it's so,
Take the Bromide and iodide salts Or else, our marble buildings
There soluble as can be Would melt away like snow.
Save silver, mercury, and lead
That precipitate as you see (Repeat with feeling)
Every single sulfate Only note is that all Lithium salts are
Is soluble , 'Tis said Soluble too!!!
'Cept barium and strontium
And calcium and lead.
Reactions Involving Ions:
Molecular vs. Ionic Equations
• Chemical Reaction can be expressed by:
–Molecular Equation (balanced chemical equation)
–Complete Ionic Equation (showing all ions in reaction)
–Net Ionic Equation (showing only those ions directly
involved in reaction)
Copper (III) sulfate reacts with sodium hydroxide to form
copper (III) hydroxide and sodium sulfate (all in water).
• Express reaction in molecular, complete ionic,
and net ionic equations
Predicting Whether a Precipitation Reaction
Occurs; Writing Equations:
a) Calcium Nitrate and Sodium Sulfate solutions are added together.
Ca(NO3)2 (aq) + Na2SO4 (aq) CaSO4 (s) + 2NaNO3 (aq)
Total Ionic Equation
Ca2+(aq)+2 NO3-(aq) + 2 Na+(aq)+ SO4-2(aq) CaSO4 (s) + 2 Na+(aq+) 2 NO3-(aq)
Net Ionic Equation
Ca2+(aq) + SO-2(aq) CaSO4 (s)
Spectator Ions are Na+ and NO3-
b) Ammonium Sulfate and Magnesium Chloride are added together.
In exchanging ions, no precipitates will be formed, so there will be no
chemical reactions occurring! All ions are spectator ions!
and ionic equations
for this reaction.
Ionic equation: Ag+(aq) + Cl-(aq) AgCl(s)
2Na (s) + Cl2(g) 2NaCl(s)
copper ( II)
out on the
Write a net ionic equation for this reaction!
Cu+2(aq) + Fe(s) Cu(s) + Fe+2(aq)
• Household Acids and Bases
Definition of Acid & Base
– Acid: substance that produces H+ ions
– Base: substance that produces OH- ions
• Bronsted & Lowry
– Acid: substance that donates a proton to
– Base: substance that accepts a proton to
Acids - A Group of Covalent Molecules Which Lose
Hydrogen Ions to Water Molecules in Solution
When gaseous hydrogen iodide dissolves in water, the attraction of the
oxygen atom of the water molecule for the hydrogen atom in HI is
greater that the attraction of the of the iodide ion for the hydrogen atom,
and it is lost to the water molecule to form an hydronium ion and an
iodide ion in solution. We can write the hydrogen atom in solution as
either H+(aq) or as H3O+(aq) they mean the same thing in solution. The
presence of a hydrogen atom that is easily lost in solution is an “Acid”
and is called an “acidic” solution. The water (H2O) could also be written
above the arrow indicating that the solvent was water in which the HI
HI(g) + H2O(L) H+(aq) + I -(aq)
HI(g) + H2O(L) H3O+(aq) + I -(aq)
HI(g) H+(aq) + I -(aq)
Figure 4.8B: Red cabbage juice added to solutions
in the beakers.
Photo courtesy of James Scherer.
Molecular representation of
NH3(aq) + H2O(l) NH4+(aq) + OH-(aq)
Reaction of nitric acid with
HNO3(aq)+ H2O(l) NO3-(aq) + H3O+(aq)
Strong Acid or Base
An acid or base that ionizes completely in
water. It is present entirely as ions; it is a
• Weak Acid or Base
• An acid or base that is only partly ionized in
water. It is present primarily as molecules and
partly as ions; it is a weak electrolyte. Weak
bases are often nitrogen bases such as NH3:
• NH3(aq) + H2O(l) →NH4+(aq) + OH-(aq)
• The most common weak acid is acetic acid:
• HC2H3O2 (aq)+ H2O(l) → H3O+(aq) + C2H3O2-(aq)
• If an acid or base is not strong, it is weak.
• Polyprotic Acid
• An acid that results in two or more acidic
hydrogens per molecule
• For example:
H2SO4, sulfuric acid
• Neutralization Reaction
• A reaction of an acid and a base that
results in an ionic compound (a salt) and
•Write the molecular, ionic, and net ionic equations for the
neutralization of sulfurous acid, H2SO3, by potassium
•(Balance the reaction and include state
•H2SO3(aq) + 2KOH(aq) 2H2O(l) + K2SO3(aq)
•H2SO3(aq) + 2K+(aq) + 2OH-(aq)
•2H2O(l) + 2K+(aq) + SO32-(aq)
•Net Ionic Equation
•H2SO3(aq) + 2OH-(aq) 2H2O(l) + SO32-(aq)
• Acid-Base Reaction with Gas Formation
• Some salts, when treated with an acid,
produce a gas. Typically sulfides, sulfites, and
carbonates behave in this way producing
hydrogen sulfide, sulfur trioxide, and carbon
The photo shows baking
soda (sodium bicarbonate)
reacting with acetic acid in
vinegar to give bubbles of
Write the reaction that’s occurring.
Molarity (Concentration of Solutions)= M
M= Moles of Solute = Moles
Liters of Solution L
solute = material dissolved into the solvent
In air , Nitrogen is the solvent and oxygen, carbon dioxide, etc.
are the solutes.
In sea water , Water is the solvent, and salt, magnesium chloride, etc.
are the solutes.
In brass , Copper is the solvent (90%), and Zinc is the solute(10%)
Preparing a Solution - I
• Prepare a solution of Sodium Phosphate by
dissolving 3.95g of Sodium Phosphate into water
and diluting it to 300.0 ml or 0.300 l !
• What is the Molarity of the salt and each of the
• Na3PO4 (s) + H2O(solvent) = 3 Na+(aq) + PO4-3(aq)
• You place a 1.62-g of potassium
dichromate, K2Cr2O7, into a 50.0-mL
volumetric flask. You then add water
to bring the solution up to the mark
on the neck of the flask. What is the
molarity of K2CrO7 in the solution?
Molar mass of K2Cr2O7 is 294 g.
50.0 x 10 L
• When a higher concentration
solution is used to make a
the moles of solute are
determined by the amount of
solution. The number of
moles of solute remains
• A saturated stock solution of NaCl is 6.00
M. How much of this stock solution is
needed to prepare 1.00-L of physiological
saline soluiton (0.154 M)?
M iVi M fV f (0.154 M )(1.00 L)
M fVf 6.00 M
Mi Vi 0.0257 L or 25.7 mL
• A procedure for determining the amount of
substance A by adding a carefully
measured volume with a known
concentration of B until the reaction of A
and B is just complete
Titration of an
amount of HCl
• Titration of an unknown amount of HCl with NaOH.
• In the titration above, the indicator changes color to
indicate when the reaction is just complete.
• Zinc sulfide reacts with hydrochloric
acid to produce hydrogen sulfide gas:
• ZnS(s) + 2HCl(aq) ZnCl2(aq) +
• How many milliliters of 0.0512 M HCl
are required to react with 0.392 g
• Molar mass of ZnS = 97.47 g
1 mol ZnS 2 mol HCl 1 L solution
0.392 g ZnS x x x
97.47 g ZnS 1 mol ZnS 0.0512 mol HCl
• = 0.157 L = 157 mL HCl solution