Solution Notes
Vocabulary
Solute: Substance being dissolved
Solvent: Substance that does the dissolving
Solution: A homogenous mixture of solute and solvent
Example
Solubility
Like dissolves Like
Polar molecules dissolve polar molecules and ionic molecules
Nonpolar molecules dissolve nonpolar molecules
Solvents
Water
and
CCl4
Which solvent will each solvent dissolve in?
NaCl
SO2
I2
Temperature can affect the solubility of a solute into a solvent
Example: Coffee mate in hot coffee and coffee mate in warm coffee
Describing a solution
Saturated solution
Unsaturated solution
Supersaturated solution
Solubility Curves
How many grams of potassium nitrate can dissolve in 100 g of water at 50C?
At 20C, a solution contains 120 g of NaNO3 in 100 g of water. Is this solution saturated,
unsaturated, or supersaturated?
Which salt shows the least change in solubility from 0 °C to 100 °C?
You need to make a solution containing 90 g of sodium nitrate in 100 g of water. What
temperature is required to make this solution?
You need to make a solution containing 150 g of potassium chloride in 300 g of water.
What temperature is required?
Which salt is most soluble at 10 °C?
Which salt is least solvent is least soluble at 60 °C?
Net Ionic Equations
Look at this reaction below
Sodium chloride reacts with silver nitrate
Balanced Reaction
Which product is aqueous and which product is a precipitate?
Is sodium and nitrate participating in the reaction? (Are they forming something
chemically NEW?)
Spectator ions: ions in a solution that do not participate in the reaction
Net Ionic Equation
Lead (II) nitrate reacts with sulfuric acid
Molecular Equation: Write out a balanced reaction
Ionic Equation: Show the individual cations and anions in the reaction.
Net Ionic Equation: Cross out the spectator ions from the ionic equation to show which
ions are rearranging the bonds to form a NEW substance.
Hydrochloric acid reacts with sodium hydroxide
Molecular Equation: Write out a balanced reaction
Ionic Equation: Show the individual cations and anions in the reaction.
Net Ionic Equation: Cross out the spectator ions from the ionic equation to show which
ions are rearranging the bonds to form a NEW substance.
Sodium phosphate reacts with iron (III) chloride
Molecular Equation: Write out a balanced reaction
Ionic Equation: Show the individual cations and anions in the reaction.
Net Ionic Equation: Cross out the spectator ions from the ionic equation to show which
ions are rearranging the bonds to form a NEW substance.
Oxidation and Reduction Reactions
Example:
Bleach contains sodium hypochorite, which releases oxygen; causing the oxidation of a
stain to a colorless form.
Oxidation gain of oxygen or loss of electrons
Reduction is loss of oxygen or gain of electrons
Substance that loses electrons is the reducing agent
The substance that accepts electrons is the oxidizing agent
Example
Mg(s) + S(s)
MgS(s)

Mg
S
Which is oxidized and which is reduced?
2Na(s) + Br2(l)
2Li(s) + F2(g) 

2NaBr
2LiF(s)
Oxidation States
Oxidation number is a positive or negative number assigned to an atom to indicate its
degree of oxidation or reduction.
Rules for assigning oxidation numbers
1. The oxidation number for a monoatomic ion is equal in magnitude and sign to its
ionic charge.
2. The oxidation number of hydrogen in a compound is +1, except in metal hydrides
such as NaH, where it is -1
3. The oxidation number of oxygen in a compound is -2
4. The oxidation number of an atom in its elemental form is 0. For example the
oxidation number for copper metal Cu(s) is 0 and the oxidation number for nitrogen
gas (N2) is 0.
5. For any neutral compound, the sum of the oxidation numbers of the atoms in the
compound must equal 0.
6. For a polyatomic ion, the sum of the oxidation numbers must equal the ionic charge
of the ion.
First element
Second Element
Overall Charge
S2O5
CO3-2
P2O5
NO3-1
PO4-3
NH4+1
What is the oxidation number of each:
Ca(ClO4)2
KClO3
Identify which atoms are oxidized and which are reduced in each reaction:
Zinc plus hydrochloric acid
Copper (I) nitrate reacts with iron.
Concentrations of Solutions
Molarity
The concentration of a solution is a measure f the amount of solute that is dissolved in a
given quantity of solvent.
Molarity (M) the number of moles of solute dissolved in one liter of solution
Molarity= moles of solute /liter of solution
Example
What is the molarity of a solution in which 107 g of sodium hydroxide in 1.0 L of solution?
What is the molarity of a solution in which 17.8 g of sodium nitrate are dissolved in 250 mL
of solution?
How many grams of potassium nitrate should be used to prepare 3 L of a 1.75 M solution?
What volume should 10.0 g of sodium chloride be diluted to in order to prepare a 0.75 M
solution?
Diluting Solutions
Molarity X Volume = Molarity X Volume
M1V1 = M2V2
How much 18 M sulfuric acid is needed to prepare 500 mL of 3.0 M solution?
To what volume should 55 mL of 12 M of hydrochloric acid should be diluted to prepare a
2.0 M solution?
Stoichiometry of Solutions
Calculate how many grams of water will be produced when 150. mL of a 1.5 M solution of
calcium hydroxide solution reacts with excess sulfuric acid?
Calculate the mass of salt that is produced when 25.0 mL of a 0.50 M solution of potassium
hydroxide reacts with excess chloric acid.
Calculate the mass of copper produced when 75.0 mL of a 1.25 M solution copper (I)
chloride reacts with excess iron. Iron will form +2 cation in the product.