Chapter 7
Driving forces for a reaction
- Forming of a solid
- Forming of water
- Transferring of electrons
- Forming of a gas
When 2 or more chemicals are brought together, any of these reactions can occur, and a chemical change or reaction is likely to take place.
Reactions in which a solid forms
The process in a chemical reaction in which a solid is formed is called precipitation.
The solid that forms is called the precipitate.
This type of reaction is known as a precipitation reaction.
Reactants—> Products
solid (s)
liquid (l)
gas (g)
aqueous solution (aq)
What happens when an ionic compound dissolves in water?
When a solid containing ions dissolves in water, the ions separate and move around independently.
Any substance that dissolves in water and produces separate ions is considered a strong electrolyte.
How to decide what products form
A solid compound must have a zero net charge. This means that the product must have both anions and cations (negative and positive ions).
ex. NaCl Na+(cation) Cl-(anion)
Solubility Rules
Soluble (aq)
NO3^-1 (aq)
Na+ (aq)
K+ (aq)
NH4+ (aq)
Cl- (aq)
ex. Ag+, Pb+2, Hg2^+2 (s)
SO4^-2 (aq)
ex. Ba+2, Pb+2, Ca+2 (s)
Insoluble
OH- (s)
ex. Na+, K+, NH4+, Ba, Ca (aq)
S2-, CO2^-3, PO4^-3 (s)
ex. Na+, K+, NH4+ (aq)
Using solubility rules to predict the products of reactions
-exchange anions
-positive in reactant goes with negative in product and negative in reactant goes with positive in product
Describing reactions in aqueous solutions
A molecular equation is an equation representing a reaction in solution and showing the reactants and products in undissociated form, whether they are strong or weak electrolytes.
A complete ionic equation is an equation that shows as ions all substances that are strong electrolytes.
Spectator ions are ions present in solution that do not participate directly in a reaction.
A net ionic equation equation includes only those compounds that undergo a change in the reaction.
Reactions that form water: acids and bases
An acid is a substance that produces H+ ions (protons) when it is dissolved in water.
A base is a substance that produces hydroxide ions (OH-) in water.
Reactions of metals with nonmetals
A reaction that involves a transfer of electrons is called an oxidation-reduction reaction.
Ways to Classify Reactions
The formation of a solid when two solutions are mixed is called precipitation.
A double displacement reaction is when the products are reversed.
An acid-base reaction involves an H+ ion that ends up in the product water.
An oxidation-reduction reaction is the process of an electron transfer.
Other ways to classify reactions
A combustion reaction is one where many chemical reactions that involve oxygen produce energy so rapidly that a flame results.
A synthesis reaction is one where a compound is formed from simpler materials.
When a compound is broken down into simpler compounds or all the way to the compound elements it is called a decomposition reaction.
CalculationsIdentify the Correct state of matter for the following compound based on the solubility rules. Compound: CaSO4
Answer: (s)
Identify the Correct state of matter for the following compound based on the solubility rules. Compound: Cu3PO4
Answer: (s)
Identify the Correct state of matter for the following compound based on the solubility rules. Compound: AlCl3
Answer: (aq)
Balance the equation:__2NaOH(aq) + __H2SO4 (aq) → __2H2O(l) + __Na2SO4 (aq)
Answer: 1:2:1:2
What type of reaction is CH4+O2 -> CO2 + H2O?
Answer: Combustion
What type of reaction is H2 +O2-> H2O?
Answer: Synthesis
What type of reaction is H2O-> H2 +O2?
Answer: Decomposition
What type of reaction is Zn +FeCl2-> Fe + ZnCl2?
Answer: Single Displacement
What type of reaction is AgNO3 (aq)+ NaCl(aq) -> AgCl(s) + NaNO3(aq)?
Answer: Double Displacement
What type of reaction is HNO3 + NaOH->H2O + NaNO3?
Answer: Acid-base reaction
What type of reaction is AgNO3 (aq)+ NaCl(aq) -> AgCl(s) + NaNO3(aq)?
Answer: Precipitation reaction
Activities:
http://www.quia.com/quiz/4514716.html?AP_rand=1385464656-quia on the solubility rules
video on solubility rules and reactions and balancing chemical equations
Video explaining the Solubility Rules