UIT 2 PRACTICE EXAM (Part 1: General Chemistry) 1. Which would be the best definition of an ionic bond? a. The attraction between the partial positive region of one molecule and the partial negative region of another molecule. b. The attraction between charged atoms after the complete transfer of an electron. c. The exchange of electrons between two atoms. d. The bond formed between salts. 2. Do covalent bonds occur between CPS atoms? 3. In the formation of the salt, sodium chloride, what does sodium do? a. gains an electron, becoming +1 b. loose an electron, becoming -1 c. gains an electron, becoming -1 d. looses an electron, becoming +1 e. shares an electron with chlorine 4. Can water separate ionic bonds formed between very powerful atoms such as hydrogen and chlorine? c. sometimes 5. Ionic bonds occur between a. electrolytes b. molecules c. ions d. a and c 6. Do ionic bonds occur between CPS atoms? 7. The sharing of electrons between two atoms results in a/an b. covalent bond c. hydrogen bond d. James Bond 8. What bond type contributes most to the development of an electrical potential (charge differences) across nerve cell and muscle cell membranes? Putman/Pierce College Biol 241 02px/20130113/Page 1
c. covalent bond 9. Would partial positive and partial negative regions develop in the formation of a covalent bond between two carbon atoms or two oxygen atoms? a. no b. yes 10. Form between electrolytes: a. hydrogen bonds b. covalent bonds c. ionic bonds 11. Very stable bonds that can t be physically separated by water: a. hydrogen bonds b. covalent bonds c. ionic bonds 12. When oxygen and hydrogen form a covalent bond, which atom attracts the shared electrons most strongly? a. oxygen b. hydrogen c. neither; they share electrons equally! 13. In a water molecule, why do the hydrogens develop a partial positive charge? a. xygen attracts the shared electrons more than hydrogen, leaving hydrogen s positive nucleus partially exposed. b. ydrogen attracts the shared electrons more than oxygen, leaving oxygen s negative nucleus partially exposed. 14. Weak but significant attractions between hydrogen of one molecule bonded to an oxygen or nitrogen AD the oxygen or nitrogen of another molecule: a. covalent bond b. ionic bond c. hydrogen bond 15. The most common bond between molecules, helping to hold macromolecules together, cause structures to stick together in the body (such as the walls of the lungs), increases blood pressure, and allows for evaporative cooling: c. covalent bond 16. The bond type holding the atoms of molecules together: c. covalent bond Putman/Pierce College Biol 241 02px/20130113/Page 2
17. Consider the above diagrams. The dotted lines represent what? a. covalent bonds between two molecules b. covalent bonds between oxygen/nitrogen and hydrogens c. ionic bond d. hydrogen bonds within a molecule e. hydrogen bonds between two molecules 18. Why does oxygen have a partial negative charge in a water molecule? a. hydrogen pulls protons more strongly than oxygen b. hydrogen pulls protons less strongly than oxygen c. oxygen pulls electrons less strongly than hydrogen d. oxygen pulls electrons more strongly than hydrogen 19. Acids are in aqueous solution. a. hydrogen ion acceptors b. covalently bonded c. hydrogen ion donors d. hydrogen bonded 20. Which would be a good base in aqueous solution? a. Cl b. a c. 3 d. b and c 21. The p of an aqueous solution is a measurement of its what? a. hydrogen ion concentration b. hydroxide ion concentration c. proton concentration d. a and c 22. What is the p of pure water? a. 3 b. 5 c. 7 d. 9 Putman/Pierce College Biol 241 02px/20130113/Page 3
23. An aqueous solution with [ + ] = 10-3 is what? a. strongly acidic b. weakly acidic c. neutral d. weakly basic e. strongly basic 24. An aqueous solution with [ + ] = 10-12 is what? a. strongly acidic b. weakly acidic c. neutral d. weakly basic e. strongly basic 25. Which p has the most hydrogen ions (protons)? a. 2.0 b. 5.0 c. 7.0 26. What do buffers do? a. absorb excess + from solution, keeping overall levels of + constant b. release + into solution when some are used, keeping overall levels of + constant c. stabilize p d. a, b and c 27. In the bicarbonate buffer system, which two chemicals combine to form carbonic acid? and sodium b. bicarbonate and water c. water and carbon dioxide d. carbon dioxide and acid 28. Acid added to the bicarbonate buffer system is absorbed, causing the immediate formation of which? c. carbonic acid d. carbonate 29. If we continue to add acid to the bicarbonate buffer system, what is formed in the end? c. carbonic acid d. bicarbonate e. a and b Putman/Pierce College Biol 241 02px/20130113/Page 4
30. ydroxide added to the bicarbonate buffer system causes the formation of which? c. water and carbon dioxide d. bicarbonate and carbonate KEY 1b, 2a, 3d, 4a, 5d, 6b, 7b, 8a, 9a, 10c, 11b, 12a, 13a, 14c, 15b, 16c, 17e, 18d, 19c, 20d, 21d, 22c, 23a, 24e, 25a, 26d, 27c, 28c, 29e, 30d Putman/Pierce College Biol 241 02px/20130113/Page 5