BP lab - Adam Romman BP Lab 6/27/07 Data Analysis 1)...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Adam Romman BP Lab 6/27/07 Data Analysis 1) Cholorform solvent Naphthalene - solute mass solvent = density * volume = 1.4832 g/mL * 50 mL = 74.16 g molality = (moles solute) / (mass solvent) moles solute = mass / molecular weight = 4.782 g / 128.171 (mol/g) = 0.037 moles molality = 0.037 / 0.074 = 0.5031 +/0 0.0001 m mass (g) mol wt napthalene 4.782 128.171 sys error 0.001 0.001 benzoic acid 4.844 122.122 sys error 0.001 0.001 volume chloroform (mL) 50 sys error 0.05 density chloroform (g/mL) 1.4832 sys error 0.0001 moles naphthalene 0.03731 sys error 7.81E-06 mass chloroform (g) 74.16 sys error 0.074328 mass chloroform (kg) 0.07416 sys error 7.43E-05 molality naphthalene soln (m) 0.5031+/- 0.0005 sys error 0.000515 2) T b = boiling point elevation K b = boiling point constant T b = K b *m K b = m/ T b = 1.86 / 0.5031 = 3.70 +/- 0.05 (K*kg)/mol literature Kb ((K*kg)/mol) 3.63 +/- 0.01 experimental Kb ((K*kg)/mol) 3.70 +/- 0.06 rand error 0.056803139 sys error 0.003265902 total error 0.056896948 The literature values are fairly close, with a difference of about 2%. When the errors of each are taken account, the values fall within the error range of one other. 3) M = (1000[g*kg^-1]* K b *g) / (G*T b ) M = molecular weight (g/mol) g = grams solute (benzoic acid) = 4.844 g G = grams of solvent = 74.16 g T b of benzoic acid = 1.10 K M = (1000*3.70*4.844)/(74.16*1.1) = 219 experimental M for benzene (g/mol) 219 +/- 9 rand error 8.57928021 sys error 1.31732692 total error 8.67982714 4) The apparent molecular weight of benzoic acid was calculated to be 219 +/- 9 g/mol. This is in between the molecular w eight of a benzoic acid monomer (~122 g/mol) and a benzoic acid dimer (~244 g/mol), as was expected. 5) M a = apparent molecular weight X m = mole fraction of monomer M m = molecular weight of monomer M d = molecular weight of dimer M a = (1 - X m ) M d + X m M m X m = (M a- M d ) / (M m- M d ) X m = (219 244) / (122 244) = 0.20 monomer M (g/mol) 122.122 dimer M (g/mol) 244.244 sys error 0.001 monomer mole fraction 0.20 +/- 0.13 dimer mole fraction 0.80 +/- 0.13 rand error 0.12 rand error 0.12 sys error 0.05 sys error 0.05 total error 0.13 total error 0.13 6) N r = moles of benzoic acid reacted to make dimer N r = initial moles moles monomer = ini moles (ini moles *monomer mole fraction) = initial moles * (1 monomer mole fraction)...
View Full Document

This note was uploaded on 09/07/2009 for the course CH N/a taught by Professor Genemcdonald during the Spring '09 term at University of Texas at Austin.

Page1 / 6

BP lab - Adam Romman BP Lab 6/27/07 Data Analysis 1)...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online