Do Now:
Water is often called the universal
solvent. Why?• Bent shape
d• Polar bonds
• Polar molecule
O
(hydrogen bonding)
H
H
d+
d+
Like dissolve like
Hydration of ionic solute
Water interacts with polar molecule
Which organic molecule
is this?
Solution
Solute
Substance in lesser
quantity
Solvent
Substance in
greater quantity
Identify the following aqueous
solutions as strong, weak or
nonelectrolytes.
 Be
Aqueous Solution
Non/weak/strong???
Glucose
Non
Ammonia
Weak
Ethanol
Non
Sodium Chloride
Strong
Acetic Acid
Weak
Hydrochloric Acid
Strong
Tap Water
Weak
Sodium Hydroxide
Strong
able to support your answers!
To quantify solution
concentration
 Molarity
= moles solute/ L solution
 Solution
Dilution: M1V1 = M2V2
 In
a chemical reaction, atoms
rearrange to form new combinations
If we can’t see atoms, how do we
know a chemical reaction has taken
place? Color Change
Formation of a solid or a gas
Emission of light
Emission or absorption of heat
Reaction Types
• Precipitation
reaction
• Neutralization
reaction
• REDOX
reaction
What happens to the atoms?
-Double Replacement
-Double Replacement
Could be…
-Combination
-Decomposition
-Displacement (Single Replacement)
-Combustion
Precipitation Reactions
 Aqueous
reactants form an insoluble
product, a solid
 Memorize solubility rules (p.144) to
predict solid product.
 Separate aqueous solutions into ions and
write net ionic equations. (Remove
spectators)
Shown below are two aqueous solutions. Volume of each
solution is 200 mL.
a.
b.
Calculate mass of ppt in g after
solutions mixed.
What are concentration (in M) of
ions in final solution. Treat each
sphere as 0.100 mol. Assume
volumes are additive.
Ba2+
ClNa+
SO42-
 Acid
Neutralization Reactions
and base react generally producing
salt and water
 Acids: proton donors
Bases: proton acceptors
 Strong Acids/Bases completely ionize
(strong electrolytes) Which are they?
 Titration – experimental procedure where
standard reacted with another solution of
unknown conc until chemical reaction is
complete (equivalence point) identified by
endpoint (indicator changes color)
At equivalence pt, mol H+ = mol OH Calculate
the concentration (in M) of
a NaOH solution if 25.0 mL were
required to titrate 10.0 mL of 2.5 M
H2SO4.
Try it without a
Calculator!!!
A
Standardization…
What does it mean?
student standardizes NaOH beginning
with the primary standard KHP.
 KHP (potassium hydrogen phthalate - KHC8H4O4) is an acid
with one acidic hydrogen and a molar
primary standard is a reagent
mass of 204.22 g/mol.Athat
is extremely pure, stable, has



no waters of hydration, and has a
high molecular weight
A sample of 0.1082 g of KHP is accurately massed.
Distilled water and phenolphthalein are added creating a
solution.
The buret is rinsed with the unknown NaOH solution and
filled
The NaOH is titrated into the KHP until a faint pink color
remains for 1 minute. 34.67 mL of NaOH is required to
reach the endpoint. Calculate the molarity of NaOH.
 Involve
Redox Reactions
a transfer of electrons
(not all are aqueous)
Could be decomposition, synthesis, single
replacement, or combustion
 Use oxidation states to keep track of e- transfer
(ox state are assigned based on rules, p.156)


ox state could be fractions or numbers you might not expect… remember
you are assigning +/- values to atoms that are covalently combined???
Bi(OH)3 + SnO22- -> SnO32- + Bi
1.
2.
3.
Assign oxidation states
Identify oxidizing and reducing
agents
Balance in basic medium ( unnecessary to do first
two steps to do this last step)
The oxidation of 25.0 mL of a solution containing
Fe2+ requires 20.0 mL of 0.0250 M K2Cr2O7 in
acidic solution. Balance the following equation
and calculate the molar concentration of Fe2+
 Cr2O72-
+ Fe2+ + H+ -> Cr3+ + Fe3+
Try it without a
Calculator!!!
What is an activity series?
Give a chemical explanation for each of the
following:
a. When calcium metal is added to a sulfuric acid
solution, hydrogen gas is generated. After a few
minutes, the reaction slows down and
eventually stops even though none of the
reactants is used up.
b. Sodium and potassium lie above copper in the
activity series. Explain why Cu2+ ions in a
CuSO4 solution are not converted to metallic
copper upon the addition of these metals.
c. A metal M reacts slowly with steam. There is no
visible change when it is placed in a pale green
iron(II) sulfate solution. Where should we place
M in the activity series?
d. Before aluminum metal was obtained by
electrolysis, it was produced by reducing its
chloride (AlCl3) with an active metal. What
metals would you use to produce aluminum in
that way?
Consider the following reagents:
35.0 g Zn
150 mL of 0.750 M AgNO3(aq)
42.0 g Cu
150 mL of 3.00 M HNO3(aq)
6.55 mL Hg
1A. Given a 500 mL Erlenmeyer flask and a balloon, can
you combine two of the reagents to initiate a chemical
reaction that will inflate the balloon? Write a balanced
chemical equation. What inflates the balloon? What is the
theoretical yield of the substance that inflates the balloon
B. Can you combine two reagents to initiate a reaction
that will produce metallic silver? Write a balanced
chemical equation. What ions are left behind in the
solution? Calculate the theoretical yield of silver.
2
3
Problem 4


Four bottles, each containing about 5 grams of finely
powdered white substance, are found in a laboratory. Near
the bottles are four labels specifying high purity and
indicating that the substances are glucose (C6H12O6),
sodium chloride (NaCl), aluminum oxide (Al2O3), and zinc
sulfate (ZnSO4).
Assume that these labels belong to the bottles and that
each bottle contains a single substance. Describe the tests
that you could conduct to determine which label belongs to
which bottle. Give the results you would expect for each
test.
 Describe
Problem 5
a laboratory procedure needed
to carry out each of the following.
 (a)
Separate a mixture of powdered
solid CaCl2 and CaCO3.
 (b)
Determine the concentration of
solute in an aqueous sodium chloride
solution and give the concentration units
that your method provides.
 (c)
Separate a mixture of two
volatile liquids.
1997 D
Problem 6
An experiment is to be performed to determine the mass
percent of sulfate in an unknown soluble sulfate salt. The
equipment shown above is available for the experiment. A
drying oven is also available.
 (a) Briefly list the steps needed to carry out this
experiment.
 (b) What experimental data need to be collected to
calculate the mass percent of sulfate in the unknown?
 (c) List the calculations necessary to determine the mass
percent of sulfate in the unknown.
 (d) Would 0.20 M MgCl2 be an acceptable substitute for
the BaCl2 solution provided for this experiment? Explain.
 What
is aqua regia?
https://www.youtube.com/watch?v=
XoqU1GfIOkI
In the second experiment, a student is given 2.94 g of a mixture containing anhydrous MgCl2 and KNO3. To determine the percentage by mass of
MgCl2 in the mixture, the student uses excess AgNO3(aq) to precipitate
the chloride ion as AgCl(s).
(d) Starting with the 2.94 g sample of the mixture dissolved in water, briefly describe the steps necessary to
quantitatively determine the mass of the AgCl precipitate.
(e) The student determines the mass of the AgCl precipitate to be 5.48 g. On the basis of this information,
calculate each of the following.
(i) The number of moles of MgCl2 in the original mixture
(ii) The percent by mass of MgCl2 in the original mixture
 Good
problems to try in book… 99,
103, 111