Can someone just help me with Questions 1 and 2?? Donald Donegood prepared a sol

Question

Can someone just help me with Questions 1 and 2??

Donald Donegood prepared a solution of mandelic acid by dissolving 1.504 grams in water and diluting to a final volume of 100.0 mL. He found the solution's pH to be 2.29. Fill in the following table and show how you obtained your results. Next Donald wanted to prepare 100.0 mL a 1.25 M solution of acetic acid from a stock solution of 2.00 M acetic acid. How many mL of acetic acid should he pipet into a 100.0 mL volumetric flask before filling it to the line with water? If a mL of commercial vinegar solution is 7.0% acidity, how many g of acetic acid are in 50.0 mL of the vinegar? (Assume the density of vinegar and acetic acid are 1.00 g/mL). What is the molarity of acetic acid in the 7.0% commercial vinegar?

Explanation / Answer

moles of mandelic acid = 1.504 / 152.15 = 9.885 x 10^-3 mol

final volume = 100.0 mL

concentration Co = 9.885 x 10^-3 / 0.1 = 0.09885

cocnetration Co = 0.09885 M

pH = 2.29

[H+] = 10^-2.29 = 5.13 x 10^-3 M

[H+] = 5.13 x 10^-3 M

[H+] = sqrt (Ka x C)

5.13 x 10^-3 = sqrt (Ka x 0.09885)

Ka = 2.66 x 10^-4

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