Chapter 4 Flashcards
Reactions in Aqueous Solutions
What is a solution?
a homogenous mixture of two or more pure substances
What is a solvent?
the substance in a solution that is present in the greatest abundance
What are the solutes?
all of the other substances in a solution (not in greatest abundance)
What is an aqueous solution?
a solution where water is the solvent
In what ways can substances dissolve in water?
- dissociation - water surrounds the separated ions (this is how ionic compounds dissolve)
- solvation - all substances dissolve by solvation, surrounding of the solute by solvent
- notes…
- molecular compounds interact with water, but most do NOT dissociate
- some molecular substances react with water when they dissolve
What is an electrolyte?
a substance that dissociates into ions when dissolved in water (not all ionic compounds dissolve in water)
What is a nonelectrolyte?
may dissolve in water, but it does not disocciate into ions when it does so
What is a strong electrolyte?
disocciates completely when dissoved in water
What is a weak electrolyte?
only disocciates partially when dissolved in water
What do we know about a liquid if it doesn’t conduct electricity?
it doesn’t have ions
Solubility Rule #1: Always Soluble?
Group 1 metals: Li-Cs; NH4⁺; NO3⁻; CH3COO⁻
Solubility Rule #2: Usually Soluble?
Halides (Cl⁻, Br⁻, I⁻) except with Ag⁺, Cu⁺, Pb²⁺, Hg2²⁺;
Sulfate, SO4²⁻, except with Ca²⁺, Sr²⁺, Ba²⁺, Pb²⁺, Hg2²⁺
Solubility Rule #3: Insoluble?
OH⁻, CO3²⁻, S²⁻, PO4³⁻ except OH⁻ with Ca²⁺, Sr²⁺, Ba²⁺
What are precipitation reactions?
they occur when two solutions containing soluble salts are mixed and an insoluble salt is produced. The solid is called a precipitate.
How do you predict whether a precipitate forms when strong electrolytes are mixed?
- note the ions present in the reactants
- consider the possible cation-anion combinations
- determine if any of the combinations are insoluble (solid needs to be a product)
