Question

calculate the pH of the following solutions. A) a solution that is 0.240 M in sodium...

calculate the pH of the following solutions. A) a solution that is 0.240 M in sodium formate (HCOONa) and 0.120 M in formic acid (HCOOH). B) a solution that is made by combining 55 mL of 6.0×10?2 M hydrofluoric acid with 125 mL of 0.12 M sodium fluoride.

Science   Chemistry   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

Apply the hendersson hasselbach equation, the pka of formic acid is 3.75 (i found it on the web)

PH = PKa + log [Base]/[Acid]

PH = PKa + log [HCOO-] / [ HCOOH ]

PH = 3.75 + log [0.24 / 0.12] = 4.05

b)

Calculate the new molarities

moles of HF = molarity * volume = 0.055 * 0.06 = 0.0033 moles

total volume = 55 + 125 = 180 ml = 0.18 L

Molarity of HF = 0.0033 / 0.18 = 0.01833 M

moles of NaF = molarity * volume = 0.12 * 0.125 = 0.015 moles

molarity NaF = 0.015 / 0.18 = 0.0833 M

PH = PKa + log [Base]/[Acid]

PH = PKa + log [F-] / [ HF ] ; pka of HF = 3.17

PH = 3.17 + log [0.0833 / 0.01833] = 3.82

*hope this helps =)

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
A) Calculate the pH of a solution that is 0.270 M in sodium formate (HCOONa) and...
A) Calculate the pH of a solution that is 0.270 M in sodium formate (HCOONa) and 0.130 M in formic acid (HCOOH). Express your answer to two decimal places. B) Calculate the pH of a solution that is 0.510 M in pyridine (C5H5N) and 0.470 M in pyridinium chloride (C5H5NHCl). Express your answer to two decimal places. C) Calculate the pH of a solution that is made by combining 55 mL of 0.060 M hydrofluoric acid with 125 mLof 0.110...
a solution that is made by combining 55 mL of 6.0×10−2 M hydrofluoric acid with 125...
a solution that is made by combining 55 mL of 6.0×10−2 M hydrofluoric acid with 125 mL of 0.11 M sodium fluoride
4.Calculate the pH of a 0.500-L solution that contains 0.15 M formic acid, HCOOH (Ka =1.8...
4.Calculate the pH of a 0.500-L solution that contains 0.15 M formic acid, HCOOH (Ka =1.8 x 10^-4), and 0.20 M sodium formate, HCOONa. Then calculate the pH of the solution after the addition of 10.0 mL of 12.0 M NaOH.
3.Calculate the pH of a solution that contains 0.250 M formic acid, HCOOH (Ka=1.8 x 10^-4),...
3.Calculate the pH of a solution that contains 0.250 M formic acid, HCOOH (Ka=1.8 x 10^-4), and 0.100M sodium formate, HCOONa after the addition of 10.0 mL of 6.00M NaOH to the original buffered solution volume of 500.0 mL.
a solution that is made by combining 55 mL of 6.0×10−2 M hydrofluoric acid with 125...
a solution that is made by combining 55 mL of 6.0×10−2 M hydrofluoric acid with 125 mL of 0.12 M sodium fluoride I kept getting around 7.7 for the pH. I found the ml of HF and NaF to be (3.3*10^-3 mol) and (1.5*10^-2) respectively. The total volume to be 0.180L. and pKa value of 3.17 with a Ka value of (6.8*10^-4). The answer given was pH = 3.83 but I can't seem to get the same answer.
Calculate the pH of a 0.16 M solution of NaCOOH (sodium formate). Ka for HCOOH (formic...
Calculate the pH of a 0.16 M solution of NaCOOH (sodium formate). Ka for HCOOH (formic acid) is 1.8x10-4
You have 1 M solutions of formic acid and sodium formate. Calculate the volume of sodium...
You have 1 M solutions of formic acid and sodium formate. Calculate the volume of sodium formate required to make 1 liter of a solution with a pH of 4.1 in which the concentration of formic acid is 0.15 M. The pKa of formic acid is 3.75.
Two buffers are prepared by adding an equal number of moles of formic acid (HCOOH) and...
Two buffers are prepared by adding an equal number of moles of formic acid (HCOOH) and sodium formate (HCOONa) to enough water to make 1.00 L of solution. Buffer A is prepared using 1.00 mol each of formic acid and sodium formate. Buffer B is prepared by using 0.010 mol of each. (Ka(HCOOH)=1.8×10−4.) Calculate the change in pH for each buffer upon the addition of 10 mL of 1.00M HCl.
29. What is the pH of an aqueous solution made by combining 40.03 mL of a...
29. What is the pH of an aqueous solution made by combining 40.03 mL of a 0.4322 M sodium fluoride with 44.86 mL of a 0.3356 M solution of hydrofluoric acid to which 3.619 mL of a 0.0543 M solution of HCl was added?
1. A buffer is made by mixing 1.250 mol formic acid, HCOOH, with 0.750 mol sodium...
1. A buffer is made by mixing 1.250 mol formic acid, HCOOH, with 0.750 mol sodium formate, HCOONa in enough water for a total volume of 1.00L. The Ka of formic acid is 1.87 x 10-4 a. What is the pH of this buffer? b. If 0.075 mol HCl is added to this buffer, what is the pH of the resulting buffer? (assume no volume changes) c. If 0.055 mol NaOH is added to this buffer, what is the pH...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT