1. Questions

chemistry

1. A solution of sodium oxalate has a pH of 7.82. The [OH-] in mol/L must be which of the following:
a) 6.18 b) 1.5 x 10-8 c) 6.6 x 10-7 d) 7.82 e) -7.82
2. When 0.93 mol of O2 and 0.56 mol of NH3 are mixed together and allowed to come to equilibrium according to the equation:
4NH3(g) + 5O2(g) 6H2O(g) + 4NO(g)
At equilibrium it is found that there are 0.77 mol of O2. Which substance has a change in number of mols of 0.192 as the system comes to equilibrium?
a) H2O b) NH3 c) O2 d) NO e) no substances change by 0.192 mol
3. At normal body temperature, Kw has a value of 2.42 x 10-14. What is the pH of a neutral solution at this temperature?
a) 7.2 b) 13.6 c) 6.8 d) 7.0 e) 6.2

  1. 👍
  2. 👎
  3. 👁
tt

  1. You would do well to make three separate posts. It takes too long to work through three problems; therefore, many profs will let the post go if they can't do it all.
    a. pH + pOH = pKw = 14
    Use the above equation to calculate pOH, then pOH = -log(OH^-).

    1. 👍
    2. 👎
    DrBob222

  2. b. You must learn to incorporate arrows. Without arrows you can't tell the difference between products and reactants.
    I would look at this.
    mols O2 initially = 0.93
    moles O2 @ equil = 0.77
    moles O2 used = 0.16

    Now convert 0.16 moles to NH3, H2O, and NO and you will find the answer. You convert by using the coefficients in the balanced equation. For example,
    moles NH3 = 0.16 mol O2 x (4 moles NH3/5 moles O2) = 0.16*(4/5) = 0.128 so NH3 can't be it.
    moles NO = 0.16mol O2 x (4 moles NO/5 moles O2) = 0.16*(4/5) = 0.128. It was zero initially so NO can't be it.
    Continue until you find the right one.

    1. 👍
    2. 👎
    DrBob222

  4. H2O ==> H^+ + OH^-
    Kw = (H^+)(OH^-) = 2.42E-14
    Remember (H^+) = (OH^-)
    Substitute and solve.
    Don't be surprised when the answer comes out something OTHER THAN 7.0.

    1. 👍
    2. 👎
    DrBob222

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    A solution containing a mixture of 0.0381 M potassium chromate (K2CrO4) and 0.0769 M sodium oxalate (Na2C2O4) was titrated with a solution of barium chloride (BaCl2) for the purpose of separating CrO42– and C2O42– by

  2. Chemistry

    The concentration of a certain sodium hydroxide solution was determined by using the solution to titrate a sample of potassium hydrogen phthalate (abbreviated KHP). KHP is an acid with one acidic hydrogen and a molar mass of

  3. chemistry

    In a volumetric analysis experiment, a solution of sodium oxalate (Na2C2O4) n acidic solution is titrated with a solution of potassium permanganate (KMnO4) according to the following balanced chemical equation:

  4. Chemistry

    1. You have been given a sample of unknown molarity. Calculate the molarity of a solution which has been prepared by dissolving 8.75 moles of sodium chloride in enough water to produce a solution of 6.22l. 2. You have a sample

  1. CHEMISTRY

    You have been given a sample of unknown molarity. Calculate the molarity of a solution which has been prepared by dissolving 8.75 moles of sodium chloride in enough water to produce a solution of 6.22l. 2. You have a sample which

  2. Chemistry

    A solution containing a mixture of 0.0492 M potassium chromate (K2CrO4) and 0.0565 M sodium oxalate (Na2C2O4) was titrated with a solution of barium chloride (BaCl2) for the purpose of separating CrO42– and C2O42– by

  3. Chemistry ! Need help.

    A buffer prepared by dissolving oxalic acid dihydrate (H2C2O4·2H2O) and disodium oxalate (Na2C2O4) in 1.00 L of water has a pH of 5.007. How many grams of oxalic acid dihydrate (MW = 126.07 g/mol) and disodium oxalate (MW =

  4. chemistry

    an aqueous solution solution of sodium borate is sometimes used to to fire-proof wood. a. what is the molarity of 2.50 L of solution that contains 1.85 moles of sodium borate? b. what is the molarity of 45.0 L of solution that

  1. Chemistry Pls Help Asap

    An excess of silver nitrate solution was added to 10.0cm3of sodium chloride solution, and 0.717g of silver chloride was precipitated. Calculate the concentration of the sodium chloride solution in mol dm-3.

  2. chemistry

    if the average concentration of PCBs in the body tissue of a human is 4.0 ppm, what mass of the PCB is present in a 64 kg person? is this a significant amount in regards to the health of the person? What is the concentration of a

  3. Chemistry- urgent!

    When a solution of sodium oxalate (Na2C2O4) is added to a solution of lanthanum (III) chloride, lanthanum oxalate (molar mass 541.86 g/mol) The balanced net ionic equation for the reaction is: 3C2O4^2- (aq) + 2La^3+ (aq) -->

  4. Chemistry

    Explain how the calculated molarity of the potassium permanganate would be affected by each of the following experimental errors. In each case, you must also state if the calculated molarity is higher or lower than the actual

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