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Exam 3A
Spring 2002

1. Complete and balance the following reactions.

a. aqueous sulfuric acid plus solid barium hydroxide

b. C6H5NH2(aq) + H2O(l)

c. C6H5NH2(aq) + HBr(aq)

d. Mg(ClO4)2(aq) + NaOH(aq)

e. NaF(aq) + Sc(NO3)3(aq)

f. H2PO4(aq) + HAsO42(aq)

g. Mn2+(aq) + H2O(l)


2. Find the pH of a 0.0010 M solution of Na2Se. Write all of the appropriate chemical reactions, and setup the problem until you are required to do algebra. Then determine the pH based on the values given on the first page of the exam. Ka for HSe = 1.0×10–11


3. A buffer is prepared to be 0.10 M NaH2PO4 and 0.10 M Na2HPO4.

a. Find the pH of the buffer at 25 oC. Write all of the appropriate chemical reactions, and setup the problem until you are required to do algebra. Then determine the pH based on the values given on the first page of the exam.

b. 0.025 moles of HCl(g) is added to 1.0 L of the buffer. Write any new chemical reactions that occur and estimate the new pH in the buffer solution. This answer is not given on the first page, but you should be able to make a reasonable estimate without doing extensive calculations.


4. Consider the solubility of lead carbonate.

a. Find the molar solubility in water. Write the appropriate chemical reactions and setup the problem until you are required to do algebra. Then determine the molar solubility based on the values given on the first page of the exam.

b. Find the molar solubility of lead carbonate in a 0.10 M solution of lead nitrate. Write the appropriate chemical reactions and setup the problem until you are required to do algebra. Then determine the molar solubility based on the values given on the first page of the exam.