1. EXPERIMENT 23 OVERVIEW

2. GOAL DETERMINE MOLAR MASS OF S x AND THE VALUE OF x

3. METHOD FREEZING POINT DEPRESSION

4. Freezing point depression can be used to find molar mass of solute ∆T f ― experiments i ― electrolyte or nonelectrolyte K f ― table or reference book

5. Solute: S x Solvent: Naphthalene i = 1K f : given ΔT f = T f,solvent − T f,solution T f,solvent : Part A T f,solution : Part B Kilogram of naphthalene: balance Mass of S x : balance

6. PROCEDURE AND SAFETY FOLLOW PROCEDURES IN LAB MANUAL EXCEPT: WORK AT BENCH USE THE SAME THERMOMETER PLACE TUBE ON BALANCE PROPERLY COVER LIDS AFTER WEIGHING DO NOT MIX SPETULAS

7. PROCEDURE AND SAFETY ALL WASTE GOES IN BROWN WASTE BOTTLE IN HOOD, NOT SINK! USE ACETONE TO RINSE RESIDUE INTO PLASTIC WASTE CONTAINER STAY AWAY FROM THE HOTPLATE WHILE COOLING RETURN ALL COMMON ITEMS

8. PROCEDURE AND SAFETY CLEAN YOUR AREA BEFORE LEAVING AND ASK FOR INSPECTION

9. DATA ANALYSIS

11. Temperature (°C) Time (min) TfTf Cooling Curve liquid liquid + solid solid

12. GRAPHING USE SOFTWARE TO FIND T f USE FULL PAGE: CHOOSE SCALE PROPERLY GIVE GRAPH A TITLE LABEL AXIS, ADD LEGEND EXAMPLE

14. Kaleidagraph SigmaPlot Origin Graphing Software