(A) if both sentences are true, (B) if both sentences are false, (C) if the first sentence is true but the second is false, and (D) if the first sentence is false but the second is true. 1. In the Winkler Titration Method, sodium thiosulfate is standardized against a known concentration of magnesium iodate. The normality (N) of a solution is always equal to its molarity (M). 2. In the experiment on determining the dissolved oxygen concentration of a water sample, the compound used to acidify the sample was hydrochloric acid. An acidic solution will have a pH greater than 7. 3. Radioactive wastes, like uranium, must be handled and disposed of according to special regulations designed to protect people and the environment. Nuclear power plants produce too much greenhouse gases due to the burning of uranium.

16. Every year, oral rehydration therapy (ORT) –the feeding of an electrolyte solution -saves the lives of countless children worldwide who become severely dehydrated as a result of diarrhea. One requirement of the solution used is that it be isotonic with human blood. An ORT solution contains 3.5 g NaCl, 1.5 g KCI, 2.9 g Na3CgH507 (sodium citrate), and 20.0 g C6H1206 (glucose) per liter. What is the freezing point of this solution? You may assume that the density of the solution is 1.00 g/mL and that the freezing point depression constant (Kf) for water is 1.86 °C/m. -0.59 oC -1.86 oC 0.00 oC +0.51 оС -7.44 oC

Suggest a reason why it is desirable to use an excess of barium ion in the precipitation.

2

A student prepares a dilute solution of sodium hydroxide, NaOH (aq), starting with 6 M sodium hydroxide. She then titrates a 1.372 g sample of KHP with the dilute sodium hydroxide solution, NaOH (aq), to a phenolphthalein end point.   A.) If the titration required 21.84 mL of sodium hydroxide, NaOH (aq), calculate the molar concentration of the sodium hydroxide solution, NaOH (aq). (Remember that KHP is potassium hydrogen phthalate, KHC8H4O4, NOT potassium hydrogen phosphorus!)   B.) The student uses the same sodium hydroxide to titrate 10.00 mL of vinegar to a phenolphthalein end point. If the titration required 27.48 mL of sodium hydroxide, NaOH (aq), calculate the molar concentration of acetic acid, HC2H3O2 (aq), in the vinegar.   C.) Calculate the mass percent of acetic acid, HC2H3O2 (aq), in the vinegar using the molar concentration for acetic acid, HC2H3O2 (aq), determined in part b and assuming the density of the solution is 1.01 g/mL.

After studying the separation scheme for Group III cations and using your background knowledge on separation of Group I and Group II cations: (a)  devise a flow chart or schematic diagram to separate and confirm the presence of the given ions in the solution below;  (b)  write the chemical formula of the precipitates formed; and (c)  provide a brief explanation about your schematic diagram.

7.A solution is prepared by dissolving 0.030 mol of potassium perchlorate in 75 mL of hot water. KClO4 dissolves according to the equation KClO4 (s) ? K+ (aq) + ClO4- (aq). Will a precipitate form if the solution is cooled to 25oC? Assume that a negligible change in volume occurs during the operations. (Ksp = 8.9 x 10-3).

A student weights out 1.118g of impure KHP, dissolves the sample in deionized water and titrate it with 0.1001 M NaOH solution. If the titration requires 27.10 mL of the NaOH solution, and none of the impurities react with NaOH, what is the percent KHP in the sample?

Consider an analyte solution of 50.0 mL of 0.050 M hydrochloric acid, HCl, titrated against 0.10 M sodium hydroxide, NaOH (d) After adding 12.50 mL of the NaOH, halfway to the equivalence point, what ions or molecules are present in the solution? (e) At the equivalence point, after adding 25.00 mL of NaOH, what ions or molecules are present in the solution? (f) Which of the species you identified in part (e) will determine the pH of the solution?

The solubility of magnesium flourish in water is 1.5*10-2 g/L. What is the solubility in grams per liter of magnesium fluoride in 0.35 M of sodium fluoride?