Exam 4

homogenous mixture in which all the material  is in the same state

• • an individual water molecule consists of two hydrogen atoms bonded to an oxygen atom in a bent (V-shaped) structure. 
• • the oxygen atom in each O–H covalent bond attracts the electrons more strongly than the H atom
• • O & H nuclei don't share the electrons equally
• – hydrogen atoms are electron-poor compared with a neutral hydrogen (charge 0) atom; have a partial positive charge, indicated by the symbol +1 
• – oxygen atom = more electron-rich than a neutral oxygen atom & has a partial negative charge, indicated by the symbol 2- 
• • Unequal distribution of charge creates a polar bond; makes them good solvents for ionic compounds
• • Individual cations and anions are called hydrated 
• ions

• any compound that can form IONS when dissolved in water

• 1) strong: constituent ions dissociate completely, producing aqueous solns that conduct electricity well
• 2) weak: produce few ions in soln; conduct electricity less well
• 3) nonelectrolytes: dissolve in water as neutral molecules; have NO effect on conductivity

molecular equation: show ALL reactants and products in molecular or ionic form

total ionic equation: show the ions & molecules as they exist IN SOLUTION

net ionic equation: shows ions that PARTICIPATE in reaction and removes spectator ions; spectator ions DO NOT participate in the reaction

• 1) single displacement reactions: one element displaces another from a compound
• AB + C --> AC + B

2) metathesis reactions (AB+CD--> AD+BC)

• - precipitation: products = insoluble substance which preciptates from soln as a solid...ex.
• Pb(NO₃)_2(aq)+2 KI_(aq)→PbI_2(s)+2KNO_3(aq)
• net: Pb²⁺_(aq)+2I^-_(aq) → PbI_2(s)

• - acid-base neutralization: products = salt & water...ex.
• NaOH(aq) + HCl(aq)→ NaCl(aq)+ H2O(l)
• net: OH-(aq) + H+(aq) → H2O(l)

• - gas formation: usally reaction of metal carbonates...ex.
• MgCO3(s)+2HCl(aq)→2Mg(Cl)2(aq)+ H2O(l) + CO2(g)

• 1) combination reactions (condensation): more than one reactant, ONE product
• A + B --> AB 

• 2) decomposition reactions (cleavage): single reactant, MORE than 1 product
• AB --> A + B

electrons are transferred between reactants; oxidation numbers of SOME elements change; at least 1 element must increase & one MUST decrease in oxidation #

- single displacement rxns are ALWAYS redox reactions

• • (mostly) any salts with Na⁺, K⁺, NH₄⁺
• • aka salts with Alkali Metals (Group I) or   NH4+ ARE soluble

1 kJ

• are soluble EXCEPT WITH CATIONS:
• -Ag+ (silver)
• -Hg 2+ (mercury)
• -Pb 2+ (lead)

- so halides = mostly soluble except for those with silver, mercury or lead in them

Compounds containing silver ions are INSOLUBLE except silver nitrate (AgNO₃)

• •number of particles
• •type of particles
• •temperature

SOLUBLE

• EXCEPTIONS: those with
• -Mg 2+
• -Ca 2+
• -Sr 2+
• -Ba 2+
• -Pb 2+

AKA all alkali earth metals EXCEPT Be 2+

SOLUBLE

• except those with
• -Ca 2+
• -Sr 2+
• -Ba 2+
• -Pb 2+

• -just...lead holds on TIGHT, most are insoluble
• -and alkali earth metals from Ca down

SOLUBLE

1) carbonates (CO3 2-)

2) phosphates (PO4 3-)

3) oxalates (C204 2-)

4) chromates (CrO4 2-)

5) metal sulfides (S 2-)

6) metal hydroxides (OH-)

7) metal oxides (metal+O something)

• *don't forget, metals are the elements on the left and middle of the periodic table
• -love, your mother