7. Which of the following concentration measures will change in value as the temperature of a solution changes?
(A) mass percent
(B) mole fraction
(C) molality
(D) molarity
(E) all of these

3. How many oxygen atoms are there in one formula unit of Ca3(PO4)2? (A)2(B)4 (C)6 (D)8 (E) none of these

4. An unknown substance dissolves readily in water but not in benzene (a nonpolar solvent). Molecules of what type are present in the substance? (A) neither polar nor nonpolar (B) polar (C) either polar or nonpolar (D) nonpolar (E) none of these

5. Which of the species below, when dissolved in H2O, will not produce a basic solution? (A) SO2 (B) NH3 (C) BaO (D) Ba(OH)2 (E) none of these

6. CaCl2(s)+2H2O(g)⇌ CaCl2 •2H2O(s)  Consider the reaction: The equilibrium constant for the reaction as written is              . (A) K=[CaCl2·2H2]/([CaCl2][H2O]2) (B) K=1/[H2O]2 (C) K=1/2[H2O] (D) K=[H2O]2 (E) K=[CaCl2·2H2O]/[H2O]2

8. A solution containing 296.6g of Mg(NO3)2 per liter has a density of 1.114 g/mL. The molarity of the solution is: (Mg(NO3)2:148.3 g/mol). (A) 2.000 M (B) 2.446 M (C) 6.001 M (D) 1.805 M (E) none of these

9. Calculate the molality of C2H5OH in a water solution that is prepared by mixing 50.0 mL of C2H5OH with 100.0 mL of H2O at 20℃. The density of the C2H5OH is 0.789 g/mL at 20℃. (C2H5OH: 46.07 g/mol. Density of H2O is 1 g/cm3). (A) 0.086 m (B) 0.094 m (C) 1.24 m (D) 8.56 m (E) none of these

10. Which statement about N2 is false? (A) It is a gas at room temperature. (B) The oxidation state is +3 on one N and -3 on the other. (C) It has one sigma and two pi bonds between the two atoms. (D) It can combine with H2 to form NH3. (E) It has two pairs of nonbonding electrons.

11. Which of these statements about benzene is true? (A) All carbon atoms in benzene are sp3 hybridized. (B) Benzene contains only π bonds between C atoms. (C) The bond order of each C—C bond in benzene is 1.5. (D) Benzene is an example of a molecule that displays ionic bonding. (E) All of these statements are false.

12. When electrons in a molecule are not found between a pair of atoms but move throughout the molecule, this is called . (A) ionic bonding (B) covalent bonding (C) polar covalent bonding (D) delocalization of the electrons (E) a dipole moment

13. Which one of the following descriptions for microelectrodes is incorrect? (A) The dimensions of such electrodes are usually smaller than about 20 μm. (B) The IR (current × resistance) drop of microelectrodes is higher than traditional electrodes. (C) Such electrodes can be used for the study of chemical processes in single cells. (D) They are also called ultramicroelectrodes or microscopic electrodes. (E) By using such electrodes, three electrodes system is not necessary.