Chemistry

Calculate the pH of a buffer that is 0.130M in NaHCO3 and 0.295M in Na2CO3

  1. 👍 0
  2. 👎 0
  3. 👁 420
  1. Okay so first you need the dissociation constant for carbonic acid (HCO3) which is 5.6e-11. Then set up an ice table. Keep in mind that you are adding an acid to an aqueous solution of sodium bicarbonate (Na2CO3) which means you will have some CO3 ions already in the solution, preventing the carbonic acid fro dissociating entirely (which is why this a buffer problem).
    NaHCO3 <-> H+ + CO3
    I…….. .130 ………… 0 ……. .295
    C……… -x …………. +x ……. +x
    E……… .130-x …….. x …….. .295+x

    Then set up your equilibrium constant
    Ka=[products]/[reactants]= [.295+x][x]/[.130-x]
    We can make the assumption that x will be so small that it will not really change anything so our equation becomes,
    (5.6*10^-11)= [.295][x]/[.130] Then solve for x and you should get 2.47e-12, which is the concentration of H+ which you can then use to determine the pH.
    pH=-log([H+])= -log(2.47e-12)= 10.61
    Hope this helped!

    1. 👍 0
    2. 👎 0
  2. Also you can use the Henderson-Hasselbalch equation which is a little easier to handle.

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chem

    1) Which solution will have the lowest OH- A) Na2CO3 B) NaHCO3 C) NaCl D) NaHSO4 E) NH4Cl 2) Which solution will be the strongest base? A) Na2CO3 B) NaHCO3 C) NaCl D) NaHSO4 E) NH4Cl 3) Which aqueous solutions are acidic? A)

    asked by Timothy on April 5, 2014
  2. Chemistry

    The volume of .150 molar NaHCO3 solution that contains 6.30 g of Na2CO3 is... a. .200 L b. 0.400 L c. .500 L d. 1.60 L e. 2.5 L I know the answer is C but I do not understand how. Can someone please help!!! M= moles of

    asked by Lucien on September 25, 2010
  3. Chemistry (mol)

    How many mol of NaHCO3 are in a 454 g box of baking soda (NaHCO3)? A. 3.81 x 10^4 mol NaHCO3 B. 1.85 x 10^–1 mol NaHCO3 C. 5.40 x 10^0 mol NaHCO3 D. 6.33 x 10^–20 mol NaHCO3 I tried doing the calculations and a came the

    asked by Michael on January 26, 2018
  4. CHEM HELP

    what is the theoretical mole ratio- NaCl to NaHCO3 How do you determine the percentage error of an experimental mole ratio It would be easier for us to help you if we had the entire problem instead of just parts of it. However,

    asked by CHEMISTRY HELP on January 2, 2007
  5. Chemistry

    Balance this equation. NaHCO3(s) + heat ----> Na2CO3(s) + H2O(l) + CO2(g). i balanced it & got: 2NaHCO3(s)+ heat -->Na2CO3(s)+ H2O(g)+CO2(g) is this right ? Determine how many moles of CO2(g) is produced when 7mols of NaHCO3 are

    asked by Hannah on February 24, 2011
  1. Chemistry

    1.2048g sample of impure Na2CO3 is dissolved and allowed to react with a solution of CaCl2 resulting CaCO3 after precipitation, filtaration and drying was found to weight 1.0362g. calculate the percentage purity of Na2CO3

    asked by Ana on February 14, 2015
  2. chemistry

    Sodium carbonate, Na2CO3(s), can be prepared by heating sodium bicarbonate, NaHCO3(s). 2NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g) Kp = 0.34 at 160 ºC If a sample of NaHCO3 is placed in an evacuated flask and allowed to achieve

    asked by Anonymous on July 1, 2014
  3. Chemistry

    Calculate the pH of the 0.20 M NH3/0.25 M NH4Cl buffer. I calculated the pH to be 9.15 What is the pH of the buffer after the addition of 10.0 mL of 0.10 M HCl to 72.5 mL of the buffer?

    asked by Cam on March 19, 2013
  4. Chemistry

    The acetate buffer were prepared by mixing 0.1 M ch3cooh with 0.1M ch3cooNa in the ratio 8:2 and 2:8. Calculate the resulting ph after the addition of 2mL of 0.1 M HCl to 10 ml of buffer 8:2 and 4ml of 0.1 M NaOH to 10 ml of

    asked by Bobby on June 2, 2016
  5. chemistry

    What mass of carbon dioxide can be produced from 4 moles of sodium bicarbonate according to the following unbalanced reaction, NaHCO3 --> Na2CO3 + CO2 + H2O?

    asked by johnny on January 12, 2016
  6. school

    What is the pH of 0.1 M formic acid solution? Ka=1.7„e10-4? What is the pH value of buffer prepared by adding 60 ml of 0.1 M CH3COOH to 40 ml of a solution of 0.1 M CH3COONa? What is the pH value of an acetate buffer (pK=4.76)

    asked by alshammari on December 11, 2011

You can view more similar questions or ask a new question.