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Monday, Feb 1, 2010. Learning Goal: To understand “likes dissolve likes” and molality calculations Pick up quiz and bookwork Bookwork questions from Friday Periods 1-2 abstract feedback Solutions and Colligative Properties wkst Freezing Point Depression / Boiling Point Elevation Homework.
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Monday, Feb 1, 2010 Learning Goal: To understand “likes dissolve likes” and molality calculations • Pick up quiz and bookwork • Bookwork questions from Friday • Periods 1-2 abstract feedback • Solutions and Colligative Properties wkst • Freezing Point Depression / Boiling Point Elevation • Homework
Ionic vs Covalent • Ionic – metal + nonmetal • Has full ( + and -) charges • Covalent – 2 or more nonmetals • Polar covalent – electrons are NOT shared equally; has partial charge • Nonpolar covalent – electrons are shared equally; no overall charge
Molality and Freezing Point Depression • molality (m) = mol solute / kg solvent • Freezing Point Depression: • Tf = (Kf) (molality) (# of particles) • Kf (H2O) = 1.86 oC/m • Boiling Point Elevation: • Tb = (Kb) (molality) (# of particles) • Kf (H2O) = 0.52 oC/m
Number of particles Ionic Compounds – will break up into + and – charges Example: NaCl = 2 particles (Na+ and Cl-) Li2O = 3 particles (2 Li+ and 1 Cl-) Covalent Compounds – remains as one particle Example: C6H12O6 = 1 particle
Homework: • Read Sec 18.3 and 18.4 on Colligative Properties • Complete Solutions and Colligative Properties wkst • Check key online • No lab notebook set up! • Bring $0.50 Wed for ice cream • Wed is a PLC day!