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Unformatted text preview: nts are earned for the correct product. One point is earned for balancing the equation for mass and charge. (ii) What happens to the pH of the sodium carbonate solution as the barium chloride is added to it? A solution of sodium carbonate is basic. When carbonate precipitates out, this decreases the pH. One point is earned for the correct answer (no explanation is required). © 2008 The College Board. All rights reserved. Visit the College Board on the Web: www.collegeboard.com. AP® CHEMISTRY 2008 SCORING GUIDELINES (Form B)
The identity of an unknown solid is to be determined. The compound is one of the seven salts in the following table. Al(NO3)3. 9H2O NaCl BaCl2. 2H2O BaSO4 CaCO3 Ni(NO3)2. 6H2O CuSO4. 5H2O Use the results of the following observations or laboratory tests to explain how each compound in the table may be eliminated or confirmed. The tests are done in sequence from (a) through (e). (a) The unknown compound is white. In the table below, cross out the two compounds that can be eliminated using this observation. Be sure to c...
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This note was uploaded on 05/05/2011 for the course CHEM 504 taught by Professor John during the Fall '11 term at American College of Computer & Information Sciences.
- Fall '11