CHE 110 Chapter Notes - Chapter 4: Lead, Equivalence Point, Standard Solution
7 May 2018
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Chapter 4: Reactions in Aqueous Solutions
I. General Properties
1) Solution
❖ Homogeneous mixture of two or more substances
2) Solute
❖ Substance in a solution that is present in a smaller amount
3) Solvent
❖ Substance in a solution that is present in a larger amount
4) Aqueous Solution
❖ Solute initially is a liquid or solid
❖ Solvent is water
5) Electrolytes
❖ Substance that, when dissolved in water, results in a solution that can conduct
electricity
❖ Strong Electrolytes
• HCl
• HNO3
• HClO4
• H2SO4
• NaOH
• Ba(OH)2
❖ Acids and bases are electrolytes
6) Non-Electrolytes
❖ Substance that, when dissolved in water, does not conduct electricity
7) Hydration
❖ The process in which an ion is surrounded by water molecules arranged in a specific
manner
❖ Helps to stabilize ions in a solution
❖ Prevents cations from combining with anions
8) Reversible Reaction
❖ Double arrow in an equation indicates the reaction can occur in both directions
9) Chemical Equilibrium
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❖ Chemical state in which no net change can be observed
❖ Acid molecules break up as fast as the ions recombine
II. Precipitation Reactions
1) Definition
❖ Results in the formation of an insoluble product
2) Precipitate
❖ Insoluble solid that separates from the solution
3) Metathesis Reaction
❖ Double Displacement Reaction
❖ Reaction that involves the exchange of parts between two compounds
III. Solubility
1) Definition
❖ The maximum amount of solute that will dissolve in a given quantity of solvent at a
specific temperature
2) A substance is said to be soluble if a fair amount of it visibly dissolves in water
3) A substance is said to be insoluble if it does not dissolve in water
4) All ionic compounds are strong electrolytes, but they are not equally soluble
5) Solubility Rules
❖ Soluble Compounds
• Compounds containing alkali metal ions (Li+, Na+, K+, Rb+, Cs+) and the
ammonium ion (NH4+)
• Nitrates, NO3
-, Bicarbonates, HCO3
-, Chlorates, ClO3
-
• Halides (Cl-, Br-, I-)
➢ Insoluble Exceptions are Halides of:
1. Ag+, Hg2+, Pb2+
• Sulfates, SO4
2-
➢ Insoluble Exceptions are Sulfates of:
1. Ag+, Ca2+, Sr2+, Ba2+, Hg2
2+, Pb2+
❖ Insoluble Compounds
• Carbonate, phosphate, chromate, sulfide
➢ Carbonates, CO3
2-
➢ Phosphates, PO4
3-
➢ Chromates, CrO4
2-
➢ Sulfides, S2-
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➢ Soluble Exceptions
1. Compounds containing alkali metal ions and the ammonium ion
• Hydroxides, OH-
➢ Soluble Exceptions
1. Compounds containing alkali metal ions and the Ba2+ ion
IV. Equations
1) Molecular Equations
❖ The formulas of the compounds are written as though all species existed as molecules
or whole units
❖ Useful because it identifies the reagents
❖ Does not describe in detail what actually is happening in solution
2) Ionic Equations
❖ Shows dissolved species as free ions
❖ Spectator Ions
• Ions that are not involved in the overall reaction
3) Net Ionic Equations
❖ Shows only the species that actually take part in the reaction
4) Procedure for Writing Ionic and Net Ionic Equations
❖ Write a balanced molecular equation for the reaction using the correct formulas for the
reactant and product ionic compounds
❖ Write the ionic equation for the reaction. The compound that does not appear as the
precipitate should be shown as free ions.
❖ Identify and cancel the spectator ions on both side of the equation.
❖ Write the net ionic equation for the reaction.
❖ Check that the charges and number of atoms balance in the net ionic equation.
V. Acid-Base Reactions
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Document Summary
Homogeneous mixture of two or more substances: solute. Substance in a solution that is present in a smaller amount: solvent. Substance in a solution that is present in a larger amount: aqueous solution. Solute initially is a liquid or solid. Substance that, when dissolved in water, results in a solution that can conduct electricity. Strong electrolytes: hcl, hno3, hclo4, h2so4, naoh, ba(oh)2. Acids and bases are electrolytes: non-electrolytes. Substance that, when dissolved in water, does not conduct electricity: hydration. The process in which an ion is surrounded by water molecules arranged in a specific manner. Helps to stabilize ions in a solution. Prevents cations from combining with anions: reversible reaction. Double arrow in an equation indicates the reaction can occur in both directions: chemical equilibrium. Chemical state in which no net change can be observed. Acid molecules break up as fast as the ions recombine. Results in the formation of an insoluble product: precipitate.
