Chapter 15 Problems

1. What is the molarity of the salt solution produced when 250. mL of 3.50 M HCL and 250. mL of 3.50 M KOH are mixed? Assume the volumes are additive.

2. What is the concentration of the ammonium chloride produced when 11 mL of 12 M HCL and 18 mL of 9.00 M NH₃ are mixed? Assume the volumes are additive.

3. If 200. mL of 0.300 M HCl solution is added to 300. mL of 0.0500 M Ba(OH)₂ solution, the resulting solution will be _________ molar BaCl₂and ________ molar in ________.

4. Consider the titration of 50.0 mL of 0.100 M HCl using a titrant of 0.200 M NaOH. Calculate the volume of titrant needed to reach the equivalence point.

5. What is the molarity of 5.00 L of HCl that has been neutralized by 10.0 L of 5 M NaOH?

6. Does 34 mL of LiOH neutralize 15 mL of 3.0 M HCl?

7. Balance the following in an acidic solution.Original Equation:  

`SO_3^(2-) (aq) + MnO_4^(-) (aq) -> SO_4^(2-) (aq) + Mn^(2+) (aq)`

8. Balance the following in an acidic solution and then a basic solution.
`MnO_4^(-) (aq) + SO_3^(2-) (aq) -> MnO_2(s) + SO_4^(2-) (aq)`

9. Balance the following equation:
Fe(OH)₃ + OCl^- ? FeO₄^2- + Cl^-  in acidic solution

10. Balance the following equation:VO₄^3- + Fe²⁺ ? VO²⁺ + Fe³⁺ in acidic solution

11. Consider the titration of 50.0 mL of 0.100 M Fe²⁺ with 0.100 M Ce⁴⁺ in a matrix of 1 M HClO₄. The reaction in this case is,

`Fe^(2+) (aq) + Ce^(4+) (aq) ? Ce^(3+) (aq) + Fe^(3+) (aq)`

Then calculate the volume of titrant needed to reach the equivalence point.

12. The amount of Fe in a 0.4891-g sample of an ore (containing Fe₂O₃) was determined by titrating with K₂Cr₂O₇. After dissolving the sample in HCl (which will not be included in the chemical equation), the iron was brought into the +2 oxidation (Fe²⁺) state using a Jones reductor. Titration to the diphenylamine sulfonic acid end point required 36.92 mL of 0.02153 M K₂Cr₂O₇. a) balance the following Redox rxn ,

`K_2 Cr_2 O_7 + Fe^(2+)+ -> Cr^(3+)+ Fe^(3+)+ K^(+)`

b) determine the moles of Fe²⁺ c) determine the grams of the ore due to the Fe²⁺ d) Report the ore’s iron content as % by weight Fe₂O_3. 

13. If 175 mL of 0.245 M HCl solution is added to 200 mL of 0.0300 M Ca(OH)₂ solution, the resulting solution will be _______ molar CaCl₂ and ________ molar in __________.

14. What volume of 0.150 M potassium hydroxide solution would completely neutralize 34.6 mL of 0.150 M H₂SO₄?

15. What is the composition of the final solution when 26.5 mL of 0.345 M HCl and 35.4 mL of 0.510 M LiOH solutions are mixed?

16. Benzoic acid, C₆H₅COOH, is sometimes used as a primary standard for the standardization of solutions of bases. a) create this molecule in Avogadro and identify which H is the acidic H (will be donated in solution). Insert an image of the molecule and in some way identify this H. b) If a 1.946 g sample of this acid is neutralized by 35.00 mL of NaOH solution. What is the molarity of the base solution? Hint: You need to first write the chemical equation.

17. Balance the following equations in both acidic and basic environments (Show the half reactions right before they are added together (after balancing all the components) and then show the balanced equation):
    1) `Cr_2 O_7^(2-) (aq) + C_2 H_5 OH(l) -> Cr^(3+) (aq) + CO_2 (g)`
    2) `Fe^(2+) (aq) + MnO_4^(-) (aq) -> Fe^(3+) (aq) + Mn^(2+) (aq)`

Helpful Hint: In Word (Ctrl)(+) gives you subscripts (repeat to come out of subscripts) and (Ctrl) (Shift) (+) gives you super scripts (repeat to come out of superscripts).

18. The iron in a 6.675 g sample containing some Fe₂O₃ is reduced to Fe²⁺. The Fe²⁺ is titrated with 14.53 mL of 0.2456 M K₂Cr₂O₇ in an acid solution. a) balance the following equation  Cr₂O₇^2- + Fe²⁺+ `->` Cr³⁺+ Fe³⁺ b) find the mass of Fe and c) Find the percentage of Fe in the sample.