General Chemistry Principles, Patterns, and Applications, 2011

sample of AuCl, what is the solubility of AuCl in each situation? The K sp of AuCl = 2.0 × 10 −13 ; log K f {[Au(CN) 2 ] − }
= 38.3.
a. pure water
b. a 1.68 M solution of NaCN
4. ♦ Almost all barium carbonate is produced synthetically. The compound is used in manufacturing clay tiles
and ceramic products as well as in cathode ray tubes and special optical glasses. BaCO 3 is synthesized by
allowing barium sulfate to react with coal at 1000°C–1200°C in a rotary kiln, followed by treatment of a
solution of the product with either CO 2 (reaction 1) or Na 2 CO 3 (reaction 2). The reactions are as follows:
BaSO 4 (s) + 4C(s) → 4BaS(s) + 4CO(g)reaction 1. BaS(s) + CO 2 (g) + H 2 O(l) → BaCO 3 (aq) +
H 2 S(g)reaction 2. BaS(s) + Na 2 CO 3 (aq) ⇌ BaCO 3 (aq) + Na 2 S(aq)
Barium carbonate has a K sp of 2.58 × 10 −9 . The pK a fo
6.97, and the pK a
or HS- H + +S2 - is 12
r H2S
.90. Given this information, answer the following questions:
H + +HS - is
a. If reaction 1 occurs, what is the pH of the solution if 80.0 g of BaS react with CO 2 in 1.00 L
of water?
b. If reaction 2 occurs, how many grams of BaCO 3 are produced by the reaction of 80.0 g of
BaS with excess Na 2 CO 3 ?
5. A person complaining of chronic indigestion continually consumed antacid tablets containing Ca(OH) 2 over a
two-week period. A blood test at the end of this period showed that the person had become anemic. Explain
the reactions that caused this test result.
6. Although the commercial production of radium has virtually ceased since artificial radionuclides were
discovered to have similar properties and lower costs, commercial radium is still isolated using essentially the
same procedure developed by Marie Curie, as outlined here. Explain what is happening chemically at each
step of the purification process. What is precipitate A? What metal ions are present in solution A? What is
precipitate B? What metal ions are present in solution B?
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