Chemistry - acids & bases

4. Calculate the pH of each of the solutions and the change in pH to 0.01 pH units caused by adding 10.0 mL of 2.37-M HCl to 320. mL of each of the following solutions.

Change is defined as final minus initial, so if the pH drops upon mixing the change is negative.

c) 0.115 M HC2H3O2
pH before mixing =
pH after mixing=
pH change =





My work:

Before Mixing:
HC2H3O2 + H2O --> (C2H3O2)- + (H3O)+
36.8 mmol 0 0
- x + x + x

1.8e-5 = x^2 / (36.8 -x)
x = .02572813 = [H3O+]

-log(.02572813) = 1.59 (this is not correct)

  1. 👍 0
  2. 👎 0
  3. 👁 126
asked by Ellen
  1. Nope. You used millimols in this and you should use molarity. Ka is 1.8E-5, yes, but that is Ka = (H3O^+)(Ac^-)/(HAc) and you must substitute M and not mmols. If acetic acid is HAc, then
    .......HAc+ + H2O ==> Ac^- + H3O^+
    I......0.15..........0......0
    C......-x.............x......x
    E.....0.115-x.........x.......x

    This gives you (H3O^+) = ? in mols/L which is concentration and you can use that to calculate pH. .

    1. 👍 0
    2. 👎 0
  2. Thank you so much! That makes sense.

    1. 👍 0
    2. 👎 0
    posted by Ellen
  3. I'm sure you picked it up but that's 0.115 M from the problem and not 0.15. My typo.

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    When 3.00 g potassium carbonate (K2CO3 ) was mixed with 20.0 mL of hydrochloric acid (HCl, 4.0M) in a calorimeter, the temperature raised 3.0 degrees Celsius. B. Calculate the enthalpy change (H) of the reaction for per mole

    asked by Luis on April 15, 2012
  2. chemistry

    calculate [h3o] in solutions. 0.040 of HCl and 0.080 HOCl. 2. calculate OH for the solutions of 0.0063 ba (OH)2 and 0.0110 of BaCl2

    asked by anonymous on April 11, 2010
  3. Chemistry

    Hydrogen peroxide, H2O2, is a colorless liquid whose solutions are used as a bleach and an antiseptic. H2O2 can be prepared in a process whose overall change is the following. H2(g) + O2(g) H2O2(l) Calculate the enthalpy change

    asked by Glenna on October 18, 2008
  4. Chemistry

    Please help me figure out where I went wrong. HNO3 + KOH -> KNO3 + H2O enthalpy change = -53.4 kJ/mol 55.0 mL of 1.30 mol/L solutions of both reactants, at 21.4°C, are mixed in a calorimeter. What is the final temperature of the

    asked by A Canadian on February 10, 2013
  5. algebra

    i dont do the solutions very well could someone help me? how many real number solutions does the equation have? 0=2x^2-20x+50 A. 1 solution B. 2 solutions C. no solutions D. infinite solutions Is it C? Also if anyone has the rest

    asked by avg joe who didnt go on April 29, 2019
  6. Chemistry

    Calculate the heat change (q) in kJ for each reaction. Assume the density of the acid solutions is 1.00 g/mL and the heat capacity is 4.184 J/g*°C. i have the Ti and Tf..what equation do i use?

    asked by ChemGeek on May 25, 2011
  7. Biology

    Zucchini cores placed in sucrose solutions at 27oC resulted in the following percent changes after 24 hours: % change in mass [Sucrose] 20 distilled water 10 0.2 M -3 0.4 M -17 0.6 M -25 0.8 M -30 1.0 M Graph the results and find

    asked by Harry on October 11, 2007
  8. Math check

    Decide whether each equation has one, no solutions, or infanatly many solutions 1.) 2(x - 3) = 2x One solution no solutions many solutions infinatly many solutions 2.) 3(y - 3?) = 2y - 9 + y One solution no solutions many

    asked by Josh on January 8, 2014
  9. Chemistry

    The ionisation of water plays an important role in the equilibria of aqueous solutions. Kw= 1.008 x 10-14 mol2 dm-6 at 298K. (a) Calculate the pH of the following solutions at 298K showing all your working. Assume full

    asked by Henry on April 22, 2012
  10. algebra

    what are the solutions to the equation 2x^2=18 the possible answers are A. 2 solutions +/-9 B. 2 solutions +/-3 C. 2 solutions +/-√3 D. No solutions. i am completely and utterly lost so if someone could help me just like figure

    asked by ugg on April 29, 2019

More Similar Questions