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Please answer the following question. For problems requiring calculations, be su

ID: 1041149 • Letter: P

Question

Please answer the following question. For problems requiring calculations, be sure to SHOW ALL WORK and GIVE ANSWERS WITH THE CORRECT NUMBER OF SIGNIFICANT FIGURES AND UNITS. Full credit will not be given for a correct answer unless all of your work is shown. POINTS WILL BE SUBTRACTED if an answer does not have the correct number of significant figures and units (5 points). Calculate the pH of a solution prepared by mixing 3.00 grams of butyric acid (HC H:02) with 0.75 grams of NaOH in water. 02) with 0.75 grams of NaOH in water. The Ka of butyric acid is 1.5 x 10.

Explanation / Answer

mass of Butyric acid= 3.00 grams

molar mass of butyric acid=88.11 gram/mole

number of moles of Butyric acid= mass/molar mass = 3.00/88.11= 0.0340 moles

mass of NaOH= 0.75 grams

molar mass of NaOH= 40.0gram/mole

number of moles of NaOH= 0.75/40,0= 0.01875 moles

CH3CH2CH2COOH     + NaOH ------------------- CH3CH2CH2COONa   + H2O

0.0340                         0.01875                           0

-0.01875                       -0.01875                         +0.01875

0.01525                               0                              +0.01875

Ka= 1.5x10^-5

-log(Ka)= -log(1.5x10^-5)

PKa= 4,82

PH= PKa + log[salt]/[acid]

PH= 4.82 + log(0.01875/0.01525)

PH= 4.909

PH= 4.91