- Report Sheet From The Procedure 1 Obtain Six 50 Ml Or 100 Ml Beakers Number Them 1 6 2 Obtain About 100 Ml Of Each 1 (44.84 KiB) Viewed 30 times
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- Report Sheet From The Procedure 1 Obtain Six 50 Ml Or 100 Ml Beakers Number Them 1 6 2 Obtain About 100 Ml Of Each 3 (36.21 KiB) Viewed 30 times
- Report Sheet From The Procedure 1 Obtain Six 50 Ml Or 100 Ml Beakers Number Them 1 6 2 Obtain About 100 Ml Of Each 4 (27.9 KiB) Viewed 30 times
- Report Sheet From The Procedure 1 Obtain Six 50 Ml Or 100 Ml Beakers Number Them 1 6 2 Obtain About 100 Ml Of Each 5 (32.12 KiB) Viewed 30 times
- Report Sheet From The Procedure 1 Obtain Six 50 Ml Or 100 Ml Beakers Number Them 1 6 2 Obtain About 100 Ml Of Each 6 (28.61 KiB) Viewed 30 times
- Report Sheet From The Procedure 1 Obtain Six 50 Ml Or 100 Ml Beakers Number Them 1 6 2 Obtain About 100 Ml Of Each 7 (34.44 KiB) Viewed 30 times
- Report Sheet From The Procedure 1 Obtain Six 50 Ml Or 100 Ml Beakers Number Them 1 6 2 Obtain About 100 Ml Of Each 8 (20.66 KiB) Viewed 30 times
- Report Sheet From The Procedure 1 Obtain Six 50 Ml Or 100 Ml Beakers Number Them 1 6 2 Obtain About 100 Ml Of Each 9 (54.53 KiB) Viewed 30 times
- Report Sheet From The Procedure 1 Obtain Six 50 Ml Or 100 Ml Beakers Number Them 1 6 2 Obtain About 100 Ml Of Each 10 (22.54 KiB) Viewed 30 times
- Report Sheet From The Procedure 1 Obtain Six 50 Ml Or 100 Ml Beakers Number Them 1 6 2 Obtain About 100 Ml Of Each 11 (24.95 KiB) Viewed 30 times
6. Obtain a pH meter that has been previously standardized Measure and record the pH of the solutions in each of the beakers. 7. Obtain a dropper bottle of 6.0 M HCl. Add 10 drops of 6.0 M HCl to each beaker and stir the solutions Buffer Capacity For the purposes of this lab, Buffer Capacity is defined as the volume of acid or base that is added to a solution before the solution changes pH by more than 1.0 units from the initial pH. The pH will begin to change quickly past that point. 8. Rinse the pH electrode with Dl water. Measure and record the pH of each solution. If the pH of a solution changes by more than 1 pH unit from the initial measurement, then that solution's acid buffer capacity has been exceeded and the solution can be discarded. In this case, it can be said that the solution has no buffer capacity 9. Add another 10 drops of 6.0 M HCl to the remaining buffer solutions, stir and record the pH of each. If any of the pH measurements differ by more than 1 pH unit from the initial measurement for that solution, discard that solution as the buffer capacity has been exceeded for that solution 10. Repeat the previous step one more time to see if the acid buffer capacities of all of the solutions have been exceeded. If the pH has not changed by 1.0 pH units from the initial pH after the addition of 30 drops, then the buffer capacity of that solution was never reached. Adding acid Report Table BU.1: pH after addition of HCI pH after additions of 10 drops of 6.0 M HCI pH after 10 drops Initial pH pH after 20 drops pH after 30 drops HCI uՐԸ HI
Adding acid Report Table BU.1: pH after addition of HCI pH after additions of 10 drops of 6.0 M HCI Initial pH pH after 10 drops HCI pH after 20 drops HCI pH after 30 drops HCI Beaker #1 2.62 1.75 1.44 1.28 Beaker #2 4.13 3.18 1.74 1.36 Beaker #3 4.51 4.10 3.36 2.08 Beaker #4 4.90 4.50 3.77 2.42 Beaker #5 5.26 4.88 4.64 3.94 Beaker #6 7.73 5.33 4.89 4.43 From the procedure 11. Rinse out all of the small beakers and mix up the buffer solutions as described in Table BU.1 again Measure each solution's pH with the pH meter and record 12. Obtain a dropper bottle of 6.0 M NaOH. Add 10 drops of 6,0 M NaOH to each beaker and stir. 13. Rinse the pH electrode with Dl water. Measure and record the pH of each solution Discard any solutions with a pH change of more than 1.0 pH units
Adding base Report Table BU.2: pH after addition of NaOH pH after additions of 10 drops of 6.0 M NaOH Initial pH pH after 10 drops NaOH pH after 20 drops NaOH pH after 30 drops NaOH Beaker #1 2.71 3.99 4.42 4.80 Beaker #2 4.10 4.52 4.87 5.82 Beaker #3 4.52 4.80 5.76 9.25 Beaker #4 4.89 5.24 6.13 9.69 Beaker #5 5.30 6.69 11.47 12.37 Beaker #6 8.15 12.42 12.66 12.79
(24pts) Concentration and pH of Buffer Solutions From the procedure 1. Calculate the concentrations of HC2H302 and C2H302 in each buffer solution by using the volumes of each solution added to the beaker and the dilution formula. Remember that each buffer solution was prepared according to Table B.1. Table BU.1: Composition of Solutions in Beakers Beaker # Volume of 0.50 M NaC2H302 (mL) Volume of 0.50 M HC2H302 (mL) 30.00 1 0.00 2 24.00 6.00 3 18.00 12.00 4 12.00 18.00 5 6.00 24.00 6 0.00 30.00
Report Table BU.3: Initial concentrations Table view List view Initial Concentrations of Conjugates in Buffer Solutions [HC2H302] (M) (C2H302") (M) Beaker #1 Beaker #2 Beaker #3 Beaker #4 Beaker #5 Beaker #6 From the procedure 2. Calculate the theoretical pH of each solution as follows: a For the undiluted acid solution in beaker 1, perform a weak acid problem to calculate the pH
Beaker #6 From the procedure 2. Calculate the theoretical pH of each solution as follows: a. For the undiluted acid solution in beaker 1, perform a weak acid problem to calculate the pH of 0.50 M HC2H302 b. Use the Henderson Hasselbalch equation from Equation BU.2 to calculate the pH of the buffer solutions in beakers 2-5 c. For the undiluted base solution in beaker 6, perform a weak base problem to calculate the pH of 0.50 M NaC H302 3. Compare the measured pH of each buffer solution to its calculated pH in Report Table BU.4. Note: Report the absolute value of the difference in pH. Report Table BU.4: Comparison of measured and calculated initial pH Table view List view Difference between measured pH and calculated theoretical pH of solutions
Difference between measured pH and calculated theoretical pH of solutions Measured pH Calculated pH ApH (do not include negative sign) Beaker #1 2.62 Beaker #2 4.13 Beaker #3 4,51 Beaker #4 4.90 Beaker #5 5.26 Beaker #6 7.73
(14pts) Buffer Capacities From the procedure 4. For this experiment, define the buffer capacity of a solution as the number of drops of either 6.0 M HCl or 6.0 M NaOH added before the pH of the solution changes by more than 1 pH unit from the initial pH measurement a. If the pH of a buffer solution changes by more than 1 pH unit during the first addition of HCI then that buffer solution's acid buffer capacity is "O drops" or "unable to buffer" In other words, if the pH changes by more than 1 pH unit after adding the first addition, then that first addition is said to have "exceeded the buffer capacity." b. If the pH of a buffer solution changes by more than 1 pH unit during the second 10 drop addition of NaOH (changed by >1 between 10 drops and 20 drops) then that buffer solution's base buffer capacity is "10 drops." c. If after 30 drops the pH of a buffer solution does not change by more than 1 pH unit from initial, then the "buffer capacity was not exceeded". In other words, it would take more than 30 drops to exceed the buffer capacity 5. Compare the acid and base buffer capacities to the concentrations of acid and base in the buffer solutions in Report Table BU 3. Review your data for any trends or patterns between buffer capacities and concentrations you may observe, Report Table BU.5a: Buffer capacities when adding acid Table view List view Buffer capacities in drops of acid Acid Rultor احقا dan made 20 dana
Buffer capacities in drops of acid Initial 10 drops 20 drops 30 drops Acid Buffer capactity Beaker 01 2.62 1.75 1.44 1.28 Choose... O drops (Unable to buffer) 10 drops acid 20 drops acid Buffer capacity was not reached Choose Choose... Beaker #2 4.13 3.18 1.74 1.36 Beaker #3 4.51 4.10 3.36 2.08 Choose Choose.. Beaker #4 4.90 4.50 3.77 2.42 Choose Choose Beaker #5 5.26 4.88 4.64 3.94 Choose Choose Beaker 16 7.73 5.33 4.89 4.43
Report Table BU.5b: Buffer capacities when adding base Table view List view Buffer capacities in drops of base Initial 10 drops 20 drops 30 drops Base Buffer capactity Beaker 01 2.71 3.99 4.42 4.80 Choose... O drops (Unable to buffer) 10 drops base 20 drops base Buffer capacity was not reached Beaker #2 4.10 4.52 487 5.82 Choose Choose Beaker #3 4.52 4.80 5.76 9.25 Choose Choose Beaker 4 4.89 524 6.13 9.69 Choose Choose Beakers 5.30 6.69 11.47 1237 Choose Choose Beaker 86 8.15 1242 1266 12.79