8.00 * 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 Volume NaOH (mL) We can use this curve to estimate the pKa of our weak acid by what is called the "half equivalence point method". The equivalence point is the middle of the steepest part of this graph. Estimate the volume of NaOH added to the titration at that point by using a rule or other straight edge to follow that point down to the x-axis. Divide that volume by 2 (half the equivalence point) and estimate the pH at that volume of NaOH using your straight edge again. pKa = pH at the half equivalence point. What do you estimate the pka to be? 3. The pka of acetic acid is 4.76. Calculate percent error between the true value and your estimated value from question 2.

A 0.1-L unbuffered solution needs the pH adjusted from 4 to 1. How many microliters of a 12 molar HCl solution need to be added to adjust the pH? Report your answer to four decimal places. For this question: Assume the volume of HCl being added is negligible and the total volume of the solution does not change. The volume of the solution is *not* 1 L like it was in the practice pools. The question requests your answer be reported in μL (microliters)!!

The following table shows the values of ionization constants for a number of acids and bases at 25 °C: Formula Ka HC2H302 1.8x10-5 HCIO2 NH3 HCIO 1.1x10-2 2.9x10-8 Kb 1.76x10-5 For the best system, calculate the ratio of the masses of the buffer components required to make the buffer. Express your answer to two significant figures. PH = 7.30

In the laboratory, a general chemistry student measured the pH of a 0.558 M aqueous solution of isoquinoline, C9H-N to be 9.557. Use the information she obtained to determine the K, for this base. K(experiment) =