Putman/Pierce College Biol 241 02px/20130113/Page 1
UNIT 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 CHNOPS atoms?
a. yes b. no
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?
a. yes b. no
c. sometimes
5. Ionic bonds occur between a. electrolytes
b. molecules c. ions d. a and c
6. Do ionic bonds occur between CHNOPS atoms?
a. yes b. no
7. The sharing of electrons between two atoms results in a/an a. ionic bond
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?
a. ionic bond b. hydrogen bond
Putman/Pierce College Biol 241 02px/20130113/Page 2 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. Oxygen attracts the shared electrons more than hydrogen, leaving hydrogen’s positive nucleus partially exposed.
b. Hydrogen 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 AND 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:
a. ionic bond b. hydrogen bond c. covalent bond
16. The bond type holding the atoms of molecules together:
a. ionic bond b. hydrogen bond c. covalent bond
Putman/Pierce College Biol 241 02px/20130113/Page 3
N H H
H
N H H
H
N H H
H
O H H
O H H
O H H
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. HCl b. NaOH c. NH3
d. b and c
21. The pH 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 pH of pure water?
a. 3 b. 5 c. 7 d. 9
Putman/Pierce College Biol 241 02px/20130113/Page 4 23. An aqueous solution with [H+] = 10-3 is what?
a. strongly acidic b. weakly acidic c. neutral d. weakly basic e. strongly basic
24. An aqueous solution with [H+] = 10-12 is what?
a. strongly acidic b. weakly acidic c. neutral d. weakly basic e. strongly basic
25. Which pH has the most hydrogen ions (protons)?
a. 2.0 b. 5.0 c. 7.0
26. What do buffers do?
a. absorb excess H+ from solution, keeping overall levels of H+ constant
b. release H+ into solution when some are used, keeping overall levels of H+ constant c. stabilize pH
d. a, b and c
27. In the bicarbonate buffer system, which two chemicals combine to form carbonic acid?
a. water 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?
a. water
b. carbon dioxide c. carbonic acid d. carbonate
29. If we continue to add acid to the bicarbonate buffer system, what is formed in the end?
a. water
b. carbon dioxide c. carbonic acid d. bicarbonate e. a and b
Putman/Pierce College Biol 241 02px/20130113/Page 5
30. Hydroxide added to the bicarbonate buffer system causes the formation of which?
a. water
b. carbon dioxide
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
