Download presentation
Presentation is loading. Please wait.
1
Chemistry 141 Monday, October 2, 2017 Lecture 12
Solution Chemistry, Part 2
2
Objectives for today Begin to gain chemical intuition about reactions in solution Understand the factors that determine solubility and solution conductivity (electrolytes) Predict whether a precipitate will form in a reaction Identify and differentiate between strong and weak acids and bases
3
Water, the universal solvent
Water is a polar molecule There is partial negative charge on the oxygen and partial positive charge on the hydrogens
4
Dissolving an ionic compound (salt)
Consist of a lattice of + (metal) and – (non-metal) ions Dissociate in water into ions Conduct electricity (electrolyte) Cl– Na+ NaCl (s) Na+ (aq) + Cl– (aq)
5
Dissolving a covalent compound
Covalent (molecular) compounds: Consist of neutral atoms (usually non-metals) bonded together in discrete molecules Dissolve in ‘like’ solvents (polar ethanol molecule in polar water) Dissociate very little
6
Electrolytes A strong electrolyte dissociates completely when dissolved in water; solution conducts electricity (e.g. soluble salts, strong acids and bases) A weak electrolyte only dissociates partially when dissolved in water (e.g., weak acids and bases – conducts weakly) A nonelectrolyte does NOT dissociate in water
7
Solubility rules Compounds containing the following ions are soluble:
- Li+, Na+, K+, Cs+, and NH4+ - nitrates (NO3–), chlorates (ClO3–), and acetates (C2H3O2–) - chlorides (Cl–), bromides (Br–), and iodides (I–) (except those of Ag+, Hg22+, Tl+, and Pb2+) - sulfates (SO42–) (except those of Ca2+, Ba2+, Pb2+, Ag+, and Hg22+) Compounds containing the following ions are insoluble: - sulfides (S2–) (except those of alkali metals, NH4+, Ca2+, and Ba2+) - carbonates (CO32–), phosphates (PO43–), and sulfites (SO32–) (except those of alkali metals and NH4+) - hydroxides (OH–)
8
Compound types and solubility
Ionic (salt) Covalent (molecule) - Made up of + and – ions - Made up of neutral atoms - Consist of metal + nonmetal - Consist of nonmetal + nonmetal - Exist as a continuous lattice of alternating + and – ions - Exist as discrete molecules - Dissociate in water - Dissociate very little in water Solutions conduct electricity (electrolytes) Solutions do not conduct electricity (non-electrolytes) Ionic Polar covalent Non-polar covalent (+2)(-2) (+1)(-1) ethanol hexane dissolves in water? NO YES increasing charge separation (use solubility rules for each case)
9
Precipitation What happens when aqueous solutions of KCl and AgNO3 are mixed?
10
Types of solution reactions
Precipitation reactions make a solid product, almost always an insoluble salt. Acid–base reactions require both an acid and a base as reactants usually form water as a product Redox reactions characterized by changes in the oxidation states of elements
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.