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Chapter 14. Compounds in Aqueous Solutions. Dissociation – separation of ions when an ionic compound dissolves. Compounds in Aqueous Solutions cont. Soluble Na, K, and NH 4 + compounds Nitrates, acetates, chlorates Chlorides --- except Ag, Hg, Pb
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Compounds in Aqueous Solutions • Dissociation – separation of ions when an ionic compound dissolves
Compounds in Aqueous Solutions cont. • Soluble Na, K, and NH4+ compounds Nitrates, acetates, chlorates Chlorides --- except Ag, Hg, Pb Sulfates --- except Ba, Sr, Pb • Insoluble Carbonates, phosphates, silicates --- except Na, K, NH4 + Sulfides --- except Ca, Sr, Na, K, NH4 + Hydroxides --- except Group 1, Ba, Sr
Compounds in Aqueous Solutions cont. • Write balanced chemical equation and identify the precipitate (insoluble product) when these solutions are mixed. • Precipitate designated as (s) or ( ); (aq) means dissolved in water • Na2CO3 and CaCl2 • AgNO3 and NaCl • Pb(NO3)2 and Kl ( a yellow precipitate is observed)
Compounds in Aqueous Solutions cont. • Ionization – formation of ions when a molecular compound dissolves
Compounds in Aqueous Solutions cont. • Hydronium Ion (H3O+)
Compounds in Aqueous Solutions cont. • Hydronium Ion is formed when a hydrogen ion attaches to a water molecule. (we will simply use H+ and not show H2O)
Electrolytes • Strong Electrolytes – all the compound which dissolves to form ions • Weak Electrolytes - only a small amount of the compound which dissolves forms ions
Colligative Properties • Ways that a solution is different then pure H2O • Lower vapor pressure (evaporates slower) • Lower freezing point • Higher boiling point • Colligative properties – properties which depend on the number of particles in a solution: the above are colligative properties • The amount of change is increased if more of the solute is dissolved
Colligative Properties • An ionic compound (electrolyte) produces more particles in the solution than the same number of moles of a molecular compound (nonelectrolyte).
Colligative Properties • C12H22O11 (s) C12H22O11 (aq) 1 mol 1 mol of particles • NaCl (s) Na+ (aq) + Cl- (aq) 1 mol 1 mol 1 mol total of 2 mol of particles • CaCl2 (s) Ca+ (aq) + 2 Cl- (aq) 1 mol 1 mol 2 mol total of 3 mol of particles
Colligative Properties • Sodium Chloride causes twice as much change as sucrose • Calcium Chloride causes 3 times and much change as sucrose