The Solution Process Edward A. Mottel Department of Chemistry Rose-Hulman Institute of Technology

6/25/2015 Solutions  Reading assignment: Zumdahl: Chapter , 17.2  Atomic level perspective  Molecular versus Ionization  Solution concentrations

C C CH 2 OH HO H H O C H C H OH C H O C CH 2 OH O C H C HO H C H sucrose C 12 H 22 O 11

O HH O HH O HH O HH O HH O HH O HH O HH O HH O HH O HH sucrose(s) + H 2 O(l)  sucrose(aq)

Water O H H O H H water has a nonlinear structure (bent molecule) water has a dipole (polar) -- ++ ++ Polar bonds form when elements of different electronegativity bond together. O H H -- ++ ++

6/25/2015 Electronegative Elements N, O, F S, Cl

6/25/2015 Where would hydrogen belong in the periodic table, if the table was organized by period and electronegativity?

C C CH 2 OH HO H H O C H C H OH C H O C CH 2 OH O C H C HO H C H O HH O HH O HH O HH O HH O HH sucrose(aq) A hydrogen bonds forms when hydrogen bridges between two very electronegative elements. intermolecular bonds

6/25/ O HH O HH O HH O HH O HH O HH O HH O HH + O HH O H H O H H O HH NaCl(s) + H 2 O(l)  Na + (aq) + Cl - (aq) rock salt

6/25/2015 Ionic Bonds Electrostatic Attraction Na + Cl – E = k · q 1 · q 2 d Compounds with ionic bonds generally have high melting points. O H H -- ++ ++

6/25/2015 Some Salts are Soluble Solubility depends on temperature and the solvent Soluble salts Group IA, NH 4 +, NO 3 –, CH 3 COO –, ClO 3 –, ClO 4 – Most halides (Cl –, Br –, I – ) ·except Ag +, Cu +, Hg 2 2+, Pb 2+, Tl + Most sulfates ·except CaSO 4, SrSO 4, BaSO 4, Ag 2 SO 4, HgSO 4, PbSO 4

6/25/2015 Things to Think About when Writing a Chemical Equation.  What is the formula of the reactant & product?  What is the phase of the reactant & product?  Does it dissolve? What would you observe? How could you predict it? Write an equation for what occurs when solid sodium hydrogen carbonate is mixed with water.

6/25/2015 Solid Sodium Hydrogen Carbonate is Mixed with Water NaHCO 3 (s)NaHCO 3 (aq) NaHCO 3 (s)Na + (aq) + HCO 3 – (aq) How could you tell? Does it ionize? NaHCO 3 (s) Na + (aq) + H + (aq) + CO 3 2– (aq)

6/25/2015 Solid Sodium Hydrogen Carbonate is Mixed with Water NaHCO 3 (s)Na + (aq) + HCO 3 – (aq) Compounds which break into ions and conduct electricity are called electrolytes.

When a salt dissolves, it breaks into its named ions. What ions form when the following salts dissolve? calcium acetate lead(II) nitrate K 2 SO 4 CuCl 2 Write an equation for the dissolution of each of the above compounds in water.

When a salt dissolves, it breaks into its named ions. Ca(CH 3 COO) 2 (s)Ca 2+ (aq) + 2 CH 3 COO – (aq) Pb(NO 3 ) 2 (s)Pb 2+ (aq) + 2 NO 3 – (aq) K 2 SO 4 (s)2 K + (aq) + SO 4 2– (aq) CuCl 2 (s)Cu 2+ ( aq) + 2 Cl – (aq)

6/25/2015 Some Salts are Not Very Soluble  Sparingly soluble salts Most hydroxides ·except Group IA, Ba(OH) 2 Sulfides ·except Group IA, Group IIA, NH 4 + Carbonates, phosphates, sulfites ·except Group IA, NH 4 +

Reactions can occur when solutions containing different ions are mixed. An aqueous solution of calcium acetate is mixed with an aqueous solution of potassium sulfate. Ca 2+ (aq) CH 3 COO – (aq) K + (aq) SO 4 2– (aq) double displacement reaction

Ca 2+ (aq) + 2 CH 3 COO – (aq) + 2 K + (aq) + SO 4 2– (aq) CaSO 4 (s) + 2 K + (aq) + 2 CH 3 COO – (aq) Ca 2+ (aq) + SO 4 2– (aq) CaSO 4 (s) total ionic equation net ionic equation

Write the net ionic equation for the reaction of lead(II) nitrate and copper(II) chloride. Pb 2+ (aq) + 2 NO 3 – (aq) + Cu 2+ (aq) + 2 Cl – (aq) PbCl 2 (s) + Cu 2+ (aq) + 2 NO 3 – (aq) Pb 2+ (aq) + 2 Cl – (aq) PbCl 2 (s)

6/25/2015

Electron Affinity and Electronegativity  Increases from the bottom to the top from the left to the right