Lab Experiment Report Template by qff14598

VIEWS: 745 PAGES: 4

Lab Experiment Report Template document sample

More Info
									Name:                                                                                         Quiz Section:
ID Number:                                                                                     Lab Partner:

 EXPERIMENT 4: THERMODYNAMICS II                                                                                                                           Note:
 THE TEMPERATURE DEPENDENCE OF THE SOLUBILITY PRODUCT, HEAT OF SOLUTION, AND                                                                               All sections of
 ENTROPY OF SOLUTION OF POTASSIUM HYDROGEN PHTHALATE                                                                                                       this report must
                                                                                                                                                           be typed

Total Points = 60 (5 notebook, 55 template)
By signing below, you certify that you have not falsified data, that you have not plagiarized any part of this lab report, an d that all calculations and responses
other than the reporting of raw data are your own independent work. Failure to sign this declaration will cost you 5 points.

Signature:


PURPOSE AND METHOD
How are the solubility products (K sp) of KHP at various temperatures determined? (3 pts)




How is Ksp in a saturated solution of KHP in 0.50 M KCl determined? (3 pts)




DATA AND CALCULATIONS

A. Flame emission determination of [K+] in the 0.50 M KCl + KHP (sat) solution
Preparation of Standards                                                                       DATA
Table 1: Volume of 5.00x10-3 M needed to make                                                  Table 2: Flame Photometer Data
50 mL of each standard solution (from prelab)                                                  Solution                [K+], (M)            Intensity
      Standard                [K+], (M)                     mL of stock                        Standard 1              7.50E-05
          1                   7.50 E-5                                                         Standard 2              1.50E-04
          2                   1.50 E-4                                                         Standard 3              2.25E-04
          3                   2.25 E-4                                                         Standard 4              3.00E-04
          4                   3.00 E-4                                                         Standard 5              3.75E-04
          5                   3.75 E-4
                                                                                                                   Temperature,oC           Intensity
                                                                                               KHP(sat) in
                                                                                               0.50 M KCl
Plot of Intensity vs [K+] (M)
Add a Trendline and Trendline Eqn and on your plot and be sure to include a titles for the plot and each axis.




                                                                                                                                                                           3 pts




                                                                                                                                                                slope              M-1
                                                                                                                                                             y-intercept
                                               +
Table 3: Flame Emission Determination of [K ] in the original sample

                    o       [K+] in Measured                                   +
                                                                           [K ] in Original Solution
   Temperature, C
                              Solution (M)           Dilution factor                   (M)


 Type the calculation you used to determine [K+] in the measured and original solutions above.

                                                                                                                                                   3 pts




B. Standardization of NaOH
Table 4: NaOH Standardization
                                 Run 1                    Run 2                Run 3**
Mass of KHP, g
moles KHP
Initial buret reading, mL
Final buret reading, mL
mL NaOH titrated
L NaOH titrated
[NaOH], moles/L

Average, [NaOH]                                                            M

 Type the calculation for determining [NaOH] for one of the runs.

                                                                                                                                                   3 pts



 **If you only performed two titrations, type the calculation that you used to determine that you did not need to do a third titration.




C. Titrations of KHP Samples with and without KCl
mL of KHP(aq) used in titrations                                           mL

 Guide for completing Table 5: Move from left to right in this table, entering your data and doing the calculations necessary for the next column.
 Calculations: a) convert T to Kelvin, 2) calculate mL of NaOH added, 3) calculate the mmoles (10-3 moles) of NaOH added (1:1 reaction, so
 moles NaOH added equal moles of HP- present), 4) molarity of HP- (from mL and moles), 5) Ksp from [HP-], and then 1/T and ln Ksp for the plot
 below. Let Excel help with the calculations: enter your data for temperature and buret readings, then type the necessary formulas in the first cell
 of each of the other columns and copy the formula to the cells below it down the column.



Table 5: Titration Data and Calculations                                   DO NOT enter the data for the solution with KCl in this table
                                                                           Final buret
                                                   Initial buret reading                 mL NaOH         mmoles HP-
    Temperature, oC          Temperature, K                                 reading                                        Molarity HP-    Ksp         1/T (in K)   ln(Ksp)
                                                            (mL)                          added        (=mmoles NaOH)
                                                                              (mL)




Type the calculations you performed for the Room Temp (~22̊ C) solution. (2pts each)

mmoles NaOH:



[HP-]:



Ksp:
Plot of ln(Ksp) vs 1/T(K)
Add a Trendline and Trendline Eqn and on your plot and be sure to include a titles for the plot and each axis.

                                                                                                                                                                   3 pts




                    slope                             K                           R                              J/mol*K
             y-intercept                                                        DHoSoln
                                                                                DSoSoln

 Typeyour calculations for DH and DS.          (2 pts each)

 DH =

 DS =




Table 6: Titration of RT (no KCl) solution with NaOH(aq) to determine [HP-]
                                                                                               mmoles*
                            Initial buret reading          Final buret        mL NaOH           NaOH
   Temperature, oC                                                                            (=mmoles             Molarity HP-
                                     (mL)                 reading (mL)         titrated
                                                                                                 HP-)
           0.0                        0.00                     0.00                 0.00        0.000                 0.000       autofills from Table 5



                                                                                              Average M


                                     mL of KHP(aq) used in titrations                       mL                                                             2 pts
                                    Ksp at room temperature (no KCl)
                                (from Table 5 and two more replicates)

                                                                                -
Table 7: Titration of RT KHP in KCl with NaOH(aq) to determine [HP ]
                                                                                               mmoles*
                            Initial buret reading          Final buret        mL NaOH           NaOH
   Temperature, oC                                                                            (=mmoles             Molarity HP-
                                     (mL)                 reading (mL)         titrated
                                                                                                 HP-)




                                                                                              Average M:

                            mL of KHP(aq) in KCl used in titrations                         mL                                                             2 pts
                            Ksp in 0.50 M KCl (from Tables 3 and 7)

   Type the calculations for Ksp in 0.50 M KCl above and the % difference between the two Ksp values you obtained.                                         4 pts

   Ksp:


   % difference : KHP vs KHP/KCl, both at room temp




RESULTS AND DISCUSSION
1. Using a 15% difference as acceptable, are the room temperature K sp values with and without KCl the same?                                2 pts




2. Based on your results at room temperature, what is the solubility of KHP in g/L                                                          3 pts




3. What will happen to the solubility and Ksp when NaOH(aq) is added to a satuared solution of KHP. Explain your reasoning.                 4 pts




4. What will happen to the solubility and Ksp when HCl(aq) is added to a saturated solution of KHP. Explain your reasoning.                 4 pts




5. Based on a previous quarter, DHoSoln = 34.1 kJ/ mole and the DSoSoln = 120 J/K·mole.                                                     3 pts
How do your results compare (calculate and comment on % difference)?




6. What is the biggest source of error in the determination of the K sp values?                                                             2 pts




Laboratory Waste Evaluation (1 pt)
Laboratory waste is considered anything generated during an experiment that is disposed of down the sewer drain, thrown in the garbage, collected in a container for disposal
by the UW Environmental Health & Safety department, or released into the environment. Based on the written lab procedure and your actions during the lab, list the identity and
approximate amount (mass or volume) of waste that you generated while performing this experiment.

								
To top