1. CHAPTER 8: REACTIONS IN AQUAUOS SOLUTIONS
ADVANCE CHEMISTRY

2. Purpose Know the general properties of solution.
Describe the precipitate formation.
Be able to tell the solubility of an solution.
Identify Spector ions.
Know how to write net ionic equation.
Describe strong and weak bases and acids.
Define oxidation and reduction.
Calculate the morality and dilution.

3. General Properties of Solution
Solutions are defined as homogeneous mixtures of two or more pure substances. (Solvent & Solute)
All solutes are either electrolytes that, when dissolved in water, has the solution conduct electricity, or nonelectrolytes that in aqueous solution does not conduct electricity.

4. Ionic & Molecular Compounds in Water
Soluble ionic compounds tend to be electrolytes. Molecular compounds tend to be nonelectrolytes, except for acids and bases.
When an ionic substance dissolves in water, the solvent pulls the individual ions from the crystal and solvates them. This process is called dissociation.
As the ions dissolves, the ions become surrounded by water molecules as shown below. The ions are said to be solvated.

6. Strong & Weak Electrolytes
A strong electrolyte dissociates completely when dissolved in water and includes:
Strong acids
Strong bases
Soluble ionic salts
A weak electrolyte only dissociates partially when dissolved in water and includes:
Weak acids
Weak bases, etc.

7. The process of dissociation and association goes on all the time, and when the two processes reach the same rate, it has reached chemical equilibrium. Such a dynamic process is called a reversible reaction.

8. Precipitate Reaction
A Precipitation Reaction is a reaction in which a precipitate forms, which is an insoluble product that comes out of solution.

10. Solubility
Solubility is the maximum amount of solute that will dissolve at a given temperature and volume and type of solvent.

11. Metathesis (Exchange) Reactions
To complete and balance the equation for a metathesis reaction, follow the steps below:
Use the chemical formulas of the reactants to determine which ions are present.
Write the chemical formulas of the products by combining the cation from one reactant with the anion of the other using the ionic charges to determine the subscripts in the chemical formulas.
Check the water solubility of the products. For a precipitation reaction to occur, at least one product must be insoluble in water.
Balance the equation

12. Molecular Equations, Ionic Equations, and Net Ionic Equations
Writing Net Ionic Equations
Write a balanced molecular equation.
Dissociate all strong electrolytes.
Cross out anything that remains unchanged from the left side to the right side of the equation.

14. Acids Acids have the following characteristics: Taste sour
change the colors of certain dyes
generally react with metals to form hydrogen gas
react with carbonates and hydrogen carbonates to form carbon dioxide gas
Aqueous solutions conduct electricity
A monoprotic acids yield on proton per molecule like HCl.
A diprotic acid is an acid that donates two protons in two steps.
A triprotic acids have three protons to donate. Hydroxide and ammonia can accept a proton, and are therefore Brønsted bases.

15. Bases Bases are characterized by: A bitter taste feel slippery
change the colors of certain dyes
aqueous base solution conduct electricity

16. Strong & Weak Acids and Bases

17. Neutralization Reactions and Salts
Generally, when solutions of an acid and a base are combined, the products are a salt and water:

18. Neutralization Reactions with Gas Formation
When a carbonate or bicarbonate reacts with an acid, the products are a salt, carbon dioxide, and water:

19. Oxidation-Reduction (Redox) Reaction
Redox reactions are essentially reactions where electrons are transferred from one species to another.
The reaction consists of two components called half-reactions.
The one where electrons are lost is called the oxidation reaction, and the other where electrons are gained is called the reduction reaction.
The species donating electrons is called the reducing agent, and the species accepting electrons is called the oxidising agent.

20. Oxidation Numbers
An oxidation number is assigned to each atom by convention and does not necessarily reflect the formal charge on the atom.
Where the oxidation number (also termed oxidation state) of an element differs between it as reactant and product, it is part of the redox process.

21. Oxidation number is assigned by the following rules:
Elements in their elemental form have an oxidation number of 0 (H in H₂ = 0).
The oxidation number of and monatomic ion is the same as its charge (K⁺ = +1).
Nonmetals tend to have negative oxidation numbers, although some are positive in certain compounds or ions.
Oxygen has an oxidation number of −2, except in the peroxide ion, in which it has an oxidation number of −1 and −½ in superoxides (e.g. KO₂).
Hydrogen is −1 when bonded to a metal, +1 when bonded to a nonmetal.
Fluorine always has an oxidation number of −1. The other halogens have an oxidation number of −1 when they are negative; they can have positive oxidation numbers, however, most notably in oxyanions.
The sum of the oxidation numbers in a neutral compound is 0.
The sum of the oxidation numbers in a polyatomic ion is the charge on the ion.
Oxidation states may be fractions also.
In most compounds, oxidation state of H is +1. But sometimes it is -1 as in hydrides (e.g. NaH).

22. Oxidation of Metals by Acids and Salts
The reaction between a metal and either an acid or a metal salt conforms to the general pattern A + BX→AX + B.

23. Writing Equations for Oxidation-Reduction Reactions
Write reactants and products and then balance the equation in the molecular equation
2 Al(s) + 6 HBr(aq) → 2 AlBr3(aq) + 3 H2(g)
Write and complete the ionic equation and cross out anything that does not change from the left side of the equation to the right. Br– is a spectator ion, so, its crossed out
2 Al(s) + 6 H+(aq) + 6 Br–(aq) → 2 Al3+(aq) + 6 Br–(aq) + 3 H2(g)
Write a net ionic equation
2 Al(s) + 6 H+(aq)→2 Al3+(aq) + 3 H2(g)

24. The Activity Series
A list of metals arranged in order of decreasing ease of oxidation is called an activity series.
The activity series can be used to predict the
outcome of reactions between metals and
either metal salts or acids.
Any metal on the list can be oxidized by the
ions of element below it.

25. Concentration of Solution
Concentration of a solution is the amount of solute in a given volume of solvent or solution.
Two solutions can contain the same compounds but be quite different because the proportions of those compounds are different
Molarity= Moles of Solute Liters of Solution ;M= n (mol) V ( dm 3 or L)
Dilution of Solutions: Quantitative analysis is the determination of the concentration of a substance in a solution. When diluting solutions we make use of the following equation:
C₁V₁ = C₂V₂ ; Moles solute before Dilution = Moles solute after Dilution

26. Solution Stoichiometry & Chemistry Analysis

27. Titrations
In titration, a solution of known concentration (standard solution) is gradually added to the solution of unknown concentration, until the reaction is complete, and the volume of the standard needed, allows the calculation of the concentration of the solution of unknown concentration.
The point at which stoichiometrically equivalent quantities are brought together is called the equivalence point.

28. References
Lecture: Theodore E. B., Eugene, H. L. H., Bruce E. B., Catherine M., Patrick W., (2011). Chemistry: The Central Science (12 Ed). Prentice Hall. USA.
Laboratory: Theodore E. B., John H. N., Kenneth C. K., Matthew S. (2011). Laboratory Experiments for Chemistry: The Central Science (12 Ed). Prentice Hall. USA.
Theodore E. B., (2011). Solutions to Exercises for Chemistry: The Central Science. Prentice Hall. USA.
John M., Robert C. F. (2010). Chemistry (4 Ed): Prentice Hall Companion Website.
Chemistry Online at
Chemistry and You at
Teachers Notes

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