perform the calculation required for100ml of 0.2 M sodium acetate buffer of pH 5.0. If you are given a bottle of sodium acetate acetate(mw =82 and a bottle of concentrated HCl of normality =11.7). After the calculation, prepare the buffer , check the pH of your calculation and comment on your result . Prepare 1:1, 1:4, 1:10, and 1:100 diluting your buffer and obtained pH reading for them

  1. 👍
  2. 👎
  3. 👁
  4. ℹ️
  5. 🚩
  1. I can get you started.
    For pH = 5.00 start with the HH equation and solve for base/acid ratio.
    5.00 = 4.74 + log(b/a)
    b/a = about 1.82 or
    base = 1.82*acid (equation 1)
    base + acid = 20 millimoles.
    Solve those two equations simultaneously. I get something like 13 for base and 7 for acid but those are approximate. You need to go through and obtain better numbers.

    You want 100 mL 0.2M buffer which is 20 millimols. I would start with 0.2 x 82 = about 16.4 g sodium acetate and this i to be divided up as 20
    .......Ac^- + H^+ ==> HAc
    You want x to be 7; therefore, 20-x = 13. Convert those to mL 11.7M HCl to be added and I'll leave the dilutions to you. You should go through a quick check to make sure what you're preparing actually is pH = 5.00
    pH = 4.74 x log(13/7) = 5.00

    1. 👍
    2. 👎
    3. ℹ️
    4. 🚩
  2. Dr. Bob222, I’m posting this because I was working on it on a word document and had to go and take care of something before I was able to finish the dilution part; I didn't want to do this much work and not be able to post it. I am at least glad that we were on the same page on how to tackle this problem.

    NaC2H3O2 + HCl --> HC2H3O2 + NaCl

    You will need the following equation:



    Solving for [A-]/[HA]


    Which should give you a ratio of 1.74

    You need 0.2 M of the buffer, so you need (100mL)*0.2M = 0.02 moles of sodium acetate/acetic acid

    0.02= A- + HA



    Substituting one equation into the other, 1.74=0.02-HA/HA

    Solving for HA, which is the amount of HCl needed, gives 0.00730 moles of HCl; this is so because HCl completely dissociates.

    0.02 moles of sodium acetate*(82 g/1 mole)= mass of sodium acetate.

    11.7N HCl=11.7M HCl

    (0.00730 moles of HCl/11.7M)*10^3= volume of HCl in mL

    100mL-volume of HCl in mL= additional volume of solvent needed.

    For the dilutions just take part of the solution and dilute it with solvent i.e., 1 part solution and 4 parts solvent for the 1:4 dilution; repeat as indicated from the stock solution that you made.

    1. 👍
    2. 👎
    3. ℹ️
    4. 🚩

Respond to this Question

First Name

Your Response

Similar Questions

  1. chemistry

    If you add 5.0 mL of 0.50 M NaOH solution to 20.0 mL to Buffer C, what is the change in pH of the buffer? (where buffer C is 8.203 g sodium acetate with 100.0 mL of 1.0 M acetic acid) I have calculated the pH of buffer C to be

  2. chem

    Which of the following could be added to a solution of sodium acetate to produce a buffer? ? A) acetic acid only B) acetic acid or hydrochloric acid C) potassium acetate only D) sodium chloride or potassium acetate E) hydrochloric

  3. Chemistry (buffers)

    Say, for example, that you had prepared a Buffer C, in which you mixed 8.203 g of sodium acetate, NaC2H3O2, with 100.0 mL of 1.0 M acetic acid. a. What would be the initial pH of Buffer C? HOW???????

  4. chem 2

    a buffer is to be prepared by adding solid sodium acetate to 0.10M CH3COOH. Which othe following concentrations of sodium acetate will produce the most effective buffer? A. 3.0M CH3COONa B 2.5M CH3COONa C 2.0M CH3COONa D 1.5M

  1. Chemistry

    The pH of sodium acetate/acetic acid buffer is 4.5 . Calculate the ratio of [CH3 COOH]/[CH3COO-]

  2. Science- Chemistry

    How many grams of sodium acetate( molar mass 82.03 g/mol) must me added to 1.00L of a 0.200M acetic acid solution to form a buffer of 4.20?Ka value for aceic acid is 1.8 x 10^-5. How do I go about finding the grams from the given

  3. chemistry

    a buffer composed of 0.50mol acetic acid and 0.50mol sodium acetate is diluted to a volume of 1.0L. The pH of the buffer is 4.74. How many moles of NaOH must be added to the buffer solution to increase its pH to 5.74?

  4. Chemistry

    What mass in grams of a 0.500 m(molal) solution of sodium acetate, CH3CO2Na, in water would you use to obtain 0.200mol of sodium acetate?

  1. Chemistry

    A buffer is prepared by mixing 205 mL of .452 M HCl and .500 L of .400 M sodium acetate. (Ka =1.80 x 10^-5) a) What is the pH? b) How many grams of KOH must be added to .500 L of the buffer to change the pH by .125 units?

  2. College Chemistry

    A buffer solution contains 0.120M acetic acid and 0.150M sodium acetate. a. How many moles of acetic acid and sodium acetate are present in 50.0 ml of solution? b. if we add 5.55 mL of 0.092M NaOH to the solution in part (a) how

  3. chemistry

    A buffer is prepared using acetic acid, CH3COOH, (a weak acid) and sodium acetate, CH3COONa (which provides acetate ions, the conjugate base), according to the following proportions: Volume of CH3COOH(aq): 131.0 mL Concentration

  4. Chemistry

    What is the [H3O+] concentration of a pH 8.2 solution produced by a buffer made from acetic acid (pKa= 4.8) and sodium acetate?

View more similar questions or ask a new question.