Not drying the crucible after washing is a bad mistake. For Part B: If the empty crucible is not heated long enough to completely dry it prior to weighing what will be the effect on the calculated percent water in the unknown? (larger or smaller than the actual value). Explain your answer as clearly as possible.

sea water is analyzed and found to contain 2.25ng of gold for each 1.00l of sea water. how many grams of gold are in 1.00m3? (note: 1ml=1cm3)

4. Why do you determine a mass by difference? You use this because it's typically more accurate. 5. What are equivalence points and end points? How do they differ? equivalence point- the point @ which stoichiometric quantities are brought together, end point- the the equivalence point is theoretical, when end poi 6. Why should the standardized NaOH solution be kept in a stoppered bottle? pr 7. What is parallax? Why should you avoid it? Parallax is the upperent displacement or the di da in direction of an object as seen from two diffe points. са It should be colded because it ca errors in volume measurements. Copyright © 2018 Pearson Education, Inc.

Name: Date: Section: Report Sheet: Determination of Molecular Weight Through Freezing Point Depression Analysis 30 Part A: Volume of Cyclohexane mL Mass of cyclohexane (d =0.7786 g/mL) 6.0 °C Freezing Point of cyclohexane 128 Part B: Molecular Weight of Naphthalene g/mol 0.23 Mass of Sample 1 Moles of Sample 1 Mass of Sample 2 0.18 Moles of Sample 2 Moles m (mol/kg solvent) T,('C) AT, Naphthalene 5.1 TRIAL 1 5.3 TRAIL 2 k, Cyclohexane CC/m) Part C: Unknown Number 0.21 0.19 Mass of Sample 1 Mass of Sample 2 Grams Unknown T,('C) AT 0.21 4.8 TRIAL 1 0.19 5.0 TRAIL 2 Moles UnknownTRIAL 1 (moles) TRIAL 2 (moles) TRIAL 1 (g/mol)TRIAL 2 (g/mol) Molecular Weight Unknown (g/mol) AVERAGE MOLECULAR WEIGHT OF UNKNOWN