light bulb
conclusion
sodium chloride (aq)
bright
strong electrolyte
sucrose solution
no light
nonelectrolyte
hydrochloric acid
bright
strong electrolyte
acetic acid (glacial)
no light
nonelectrolyte
acetic acid (dilute)
dim
weak electrolyte
dim
weak electrolyte
bright
strong electrolyte
no light
nonelectrolyte
no light
nonelectrolyte
gatorade
copper (II) nitrate
water
isopropyl alcohol
What makes a compound a strong electrolyte?
Our strong electrolytes are hydrochloric acid, copper (II) nitrate, sodium chloride.
2 ionic compounds. 1 dilute molecular acid.
What makes a compound a weak electrolyte?
Our weak electrolytes are gatorade and dilute acetic acid.
0 ionic compounds. 1 dilute salt solution. 1 dilute molecular acid.
What makes a compound a nonelectrolyte?
Water, isopropyl alcohol, sucrose, glacial acetic acid.
4 molecular compounds. 1
Electrolytes Continued
Ionic compounds are strong electrolytes. Strong acids are also strong electrolytes.
Why?
Ionic compounds dissociate upon dissolving. Each ion separates from the lattice and is surrounded by water molecules. Once charges are in solution they may move between electrodes.
Molecular compounds do not dissociate. Each molecule in the solid state is neutral. Upon dissolving each neutral molecule is solvated.
Molecular acids to not dissociate. They ionize on dissolving. This is a chemical reaction that occurs with water and the products are ions.
Strong acids ionize completely. Weak acids only partially ionize.
This is true for weak bases too.
Acid­­ H+ donor
Base­­ H+ acceptor
2
Strong Acids
hydrochloric acid
hydrobromic acid
hydroiodic acid
nitric acid
sulfuric acid
perchloric acid
3
Precipitation reactions
A precipitate is a solid that forms from a solution. Often they are double replacement reactions (reactions where ions swap partners). To predict whether a precipitation reaction occurs use the solubility rules.
If one of the potential products is insoluble, then the reaction occurs. If not, then no reaction.
Write the equation for the addition of aqueous potassium iodide to aqueous lead (II) nitrate.
molecular equation
ionic equation
since K+ and NO3­ do nothing, they are spectator ions
4
K+ and NO3­ do nothing. They are aqueous on both sides, so they are called spectator ion.
The net ionic equation leaves the spectator ions out.
5
6
Solubility rules:
1. All nitrates and acetates are soluble
2. All group I and ammonium salts are soluble.
3. Cl­, Br­, and I­ are soluble except Ag+, Pb2+, and Hg22+
4. sulfates are soluble except for Ag+, Pb2+, Ba2+ and Hg2+. Sr2+ and Ca2+ are partially soluble.
5. Carbonates and phosphates, sulfides are generally insoluble, except for group I and ammonium.
6. OH­ are insoluble except for group I, ammonium, Ba2+, Ca2+ (partially soluble)
7
silver nitrate solution is added to a potassium sulfate solution. Does a reaction occur? If so write the molecular, ionic and net ionic equations.
(aq)
(aq)
(s)
8
Acid­Base Neutralization reactions
Acid + Base
a salt + water
Sulfuric acid reacts with sodium hydroxide
H2SO4 (aq) +
NaOH(aq)
Water is a product. The salt is the cation from the base combined with the anion from the acid in the correct ratio. The salt for the above reaction is sodium sulfate. The formula for sodium sulfate is Na2SO4. Because all sodium salts are soluble the salt formed in this reaction remains aqueous. Water is a liquid.
Na2SO4 + 2 H
2O(l)
(aq)
H2SO4 (aq) + 2 NaOH(aq)
The ionic equation is 2 H+(aq) + SO42­(aq) + 2Na+(aq) + 2 OH­(aq)
2Na+(aq) + SO42­(aq) +2 H2O(l)
The net ionic equation is
2 H+(aq) + 2 OH­(aq)
2 H2O(l)
Ba(OH)2(aq) + H3PO4(aq) 9
Acid + metal carbonate (or bicarbonate) forms a salt + water + carbon dioxide
Write the equation for hydrochloric acid + arm and hammer solid
limestone + nitric acid
calcium hydrogen carbonate solution + phosphoric acid
10
Redox reactions­­electron transfer reactions
Remember OIL RIG (Oxidation Is Loss, Reduction Is Gain) of electrons
or LEO says GER (Loss of Electrons is Oxidation, Gain of Electrons is Reduction)
Single replacement reactions.
Element + Ionic Compound ­­> Ionic Compound + element
Refer to the activity series of metals. Metals at the high end of the activity series can replace those at the bottom.
11
Magnesium sulfate + copper
hydrochloric acid + silver
aluminum + sulfuric acid
zinc + silver nitrate
magnesium + lead (II) nitrate
zinc sulfate + copper (II) chloride
potassium hydroxide + iron (III) nitrate
potassium + water
12
Predict whether the following reactions occur. If they do write the balanced equation.
Magnesium sulfate + copper
hydrochloric acid + silver
aluminum + sulfuric acid
zinc + silver nitrate
magnesium + lead nitrate
13
Single replacement of halides
We can write redox processes as half equations.
14
Write REDOX half equations and the net ionic equation for the reaction of magnesium and hydrochloric acid.
15
assign the oxidation numbers in the following
16
assign the oxidation numbers in the following
17
What is the oxidizing agent and the reducing agent in:
18
19
For each of the following reactions that occur, identify the type of reaction, complete a molecular equation, an ionic equation, and a net ionic equation. Include state symbols. A. Na2SO4 (aq) + Ba(NO3)2 (aq) Reaction type: Molecular equation: Ionic equation: Net ionic equation: B. Al (s) + MnCl2 (aq) Reaction type: Molecular equation: Oxidation half reaction:
Reduction half reaction:
Net ionic equation: 20
Concentrations of solutions
How much solute is dissolved in a specified amount of solvent, or a specified amount of solution.
% mass
Molarity is convenient, because if you know it, then you only need volume to count moles of solute (you do not need molar mass!)
21
How to make a solution of known molarity.
See the Chang Supersite
I want to make a 2.00 L of 0.200 M hydrochloric acid solution. I have 12.0 M HCl. How do I do it?
22
Solution stoichiometry
28.46 mL of 0.150 M sodium hydroxide was required to titrate 0.0250 L of sulfuric acid to the equivalence point. What is the molarity of the sulfuric acid?
23
24
25
How many moles of aluminum ions are there in 100.0 mL of 0.137 M aluminum sulfate? How many moles of sulfate ions? How many O atoms are there in the sample?
26
A 34.7 mL, 1.66 M KMnO4 solution is mixed with 16.7 mL of 0.891 M KMnO4 solution. Calculate the concentration of the final solution.
27
What is the concentration of the sulfate ion when 25.0 mL of 0.230 M sodium sulfate are mixed with 50.0 mL of 0.200 M aluminum sulfate? Assume volumes of solutions are additive. 28
Solubility curves show the solubility of a substance at different temperatures.
Solubility the mass of solute that can dissolve in a specified amount of solvent at a given temperature.
When no more solute can be dissolved in solvent at a given temperature, the solution is SATURATED.
Less than the maximum = UNSATURATED
More than the maximum = SUPERSATURATED
29
Which substance is the most soluble at 15 degrees?
SODIUM NITRATE
How much potassium dichromate will dissolve in 40.0 g water at 50 degrees?
If a saturated solution of lead nitrate in 200 g water at 40 degrees is cooled to 10 degrees how much will crystallize?
30
Calculate the volume in mL of a solution required to provide the following. (b) 4.10 g of ethanol from a 1.50 M solution 31
A 25.00 mL solution of potassium nitrate (KNO3) was diluted to 125.0 mL, and 25.00 mL of this solution were then diluted to 1.000 103 mL. The concentration of the final solution is 0.00436 M. Calculate the concentration of the original solution.
32
A 25.00 mL solution of potassium nitrate (KNO3) was diluted to 125.0 mL, and 25.00 mL of this solution were then diluted to 1.000 103 mL. The concentration of the final solution is 0.00436 M. Calculate the concentration of the original solution.
33
How many grams of NaCl are required to precipitate most of the Ag+ ions from 3.20 102 mL of 0.0113 M AgNO3 solution?
34
Calculate the mass of the precipitate formed when 2.27 L of 0.0750 M Ba(OH)2 are mixed with 3.46 L of 0.0664 M Na2SO4.
35
Milk of magnesia is an aqueous suspension of magnesium hydroxide [Mg(OH)2] used to treat acid indigestion. Calculate the volume of a 0.028 M HCl solution (a typical acid concentration in an upset stomach) needed to react with two spoonfuls (approximately 10 mL) of milk of magnesia [at 0.080 g Mg(OH)2/mL].
36
Calculate the volume of a 0.180 M CuSO4 solution that would react with 6.65 g of zinc.
37
A 4.267 g sample of a monoprotic acid was dissolved in water. It took 15.24 mL of a 0.1578 M NaOH solution to neutralize the acid. Calculate the molar mass of the acid.
38
Calculate the volume in mL of a 1.420 M NaOH solution required to titrate the following solutions. (b) 25.00 mL of a 1.500 M H2SO4 solution
39
Iron(II) can be oxidized by an acidic K2Cr2O7 solution according to the net ionic equation. Cr2O72­ + 6 Fe2+ + 14 H+ 2 Cr3+ + 6 Fe3+ + 7 H2O
If it takes 32.0 mL of 0.0250 M K2Cr2O7 to titrate 25.0
mL of a solution containing Fe2+, what is the molar concentration of Fe2+?
Cr2O72­ + 6 Fe2+ + 14 H+ 2 Cr3+ + 6 Fe3+ + 7 H2O
40
If 70.0 mL of 0.150 M CaCl2 is added to 35.0 mL of 0.100 M AgNO3, what is the mass in grams of AgCl precipitate?
41
Calculate the volume in mL of a solution required to provide the following. (a) 2.14 g of sodium chloride from a 0.150 M solution 42