Lab10%20Report

# Lab10%20Report - 7 From your graph calculate S in J/molK 8...

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Experiment 10 GSIs Name_________________________________ Report Sheet Your Name_________________________________ Partners_________________________________ ___________________________________ Table 1. Class titration data and calculation results (or instead attach data) Group Temp. (K) Volume HCl (L) moles of H 3 O + of OH - moles of B 4 5 (OH) -2 Sample size (L) M B (moles/L) K 1/T lnK 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 Make a van’t Hoff plot of lnK vs. 1/T. Fit the data to a straight line and report the equation for the line and the R 2 value. Attach the graph to your report sheet. Calculations: 1. What temperature was your solution that you titrated in Kelvin? 2. Show a sample calculation for the determination of the number of moles of OH - in your titration.

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3. Show a sample calculation for the determination of the number of moles of B 4 O 5 (OH) 4 -2 in your titration. 4. Calculate the molarity of the dissolved tetraborate ion, B 4 O 5 (OH) 4 -2 (aq), in your starting solution. 5. Write the equilibrium expression for this reaction 6. Calculate the value of the equilibrium constant at the temperature you measured.
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Unformatted text preview: 7. From your graph, calculate S in J/molK. 8. From your graph, calculate H in kJ/mol. 9. Calculate G in kJ/mol for 30C. [ ] (l) O H 8 (OH) O B Na 2 (s) O H 8 (OH) O B Na 2 2 4 5 4 eq 2 4 5 4 2 + + + Results and Discussion: 10. What does the term standard conditions mean? 11. What does the value of G at tell you about K sp at 30 C? 12. Under standard conditions does the solvation reaction favor products or reactants? 13. If G is positive (it should be), why does some of the borax still dissolve at room temperature? (Hint: what is the difference between G and G ?) 14. Does your value for H suggest that the solvation of borax is endothermic or exothermic? 15. Explain why this result is consistent with the observation that more borax dissolved at higher temperatures....
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## This note was uploaded on 09/12/2009 for the course CHEM 1A taught by Professor Nitsche during the Spring '08 term at Berkeley.

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Lab10%20Report - 7 From your graph calculate S in J/molK 8...

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