Chem108Fall13-PT-Ch12 PDF

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Chem108Fall13-PT-Ch12...

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Chem 108 Practice Test Chapter 12 I. Multiple Choice. 1. Which one of the following substances will have both dispersion forces and dipole-dipole forces? A) HCl B) BCl3 C) Br2 D) H2 E) CO2 Ans: A Category: Medium Section: 12.2 2.Which one of the following substances should exhibit hydrogen bonding in the liquid state? A) PH3 B) H2 C) H2S D) CH4 E) NH3 Ans: E Category: Medium Section: 12.2 3. Which of the following substances should have the lowest boiling point? A) CBr4 B) CBr3F C) CBr2F2 D) CBrF3 E) CF4 Ans: E Category: Medium Section: 12.2 4.Which of the following liquids would have the highest viscosity at 25°C? A) CH3OCH3 B) CH2Cl2 C) C2H5OH D) CH3Br E) HOCH2CH2OH

Ans: E

Category: Medium

Section: 12.3

5.Which of the following characteristics indicates the presence of weak intermolecular forces in a liquid? A) a low heat of vaporization D) a high boiling point B) a high critical temperature E) None of the above. C) a low vapor pressure Ans: A Category: Easy Section: 12.6 6.For which of the following species are the dispersion forces strongest? A) C4H10 B) C5H12 C) C6H14 D) C7H16 E) C8H18 Ans: E Category: Medium Section: 12.2 7.Which of the responses includes all of the following that can form hydrogen bonds with water molecules? (1) Na+ (2) CH3COOH (3) C2H6 (4) CH3NH2 A) (1) and (2) B) (1) and (3) C) (2) and (3) D) (2) and (4) E) (3) and (4) Ans: D Category: Medium Section: 12.2 8.An example of a covalent network solid is A) diamond. B) potassium. C) iodine.

D) E)

sodium chloride. None of these.

Ans: A

Category: Medium

Section: 12.4

9.The number of atoms in a body-centered cubic unit cell is A) 1. B) 2. C) 3. D) 4. E) 8. Ans: B Category: Medium Section: 12.4 10. A liquid boils when its A) vapor pressure is exactly 1 atmosphere. B) vapor pressure is equal to, or greater than, the external pressure pushing on it. C) temperature is equal to 273 K (standard temperature). D) temperature is greater than room temperature. Ans: B Category: Medium Section: 12.6 11. Which of the following is not an endothermic process? A) melting of a solid D) condensation of water vapor B) vaporization E) sublimation of dry ice C) raising the temperature of a gas Ans: D Category: Easy Section: 12.6 12. Acetic acid has a heat of fusion of 10.8 kJ/mol and a heat of vaporization of 24.3 kJ/mol. What is the expected value for the heat of sublimation of acetic acid? A) 35.1 kJ/mol

B) C) D) E) Ans:

–13.5 kJ/mol +13.5 kJ/mol –35.1 kJ/mol Not enough information is given to answer the question. A Category: Medium Section: 12.6

13. Calculate the amount of heat needed to melt 2.00 kg of iron at its melting point (1,809 K), given that Hfus = 13.80 kJ/mol. A) 494 kJ B) 27,600 kJ C) 27.6 kJ D) 27,600 J E) 25,000 kJ Ans: A Category: Medium Section: 12.6 14. The vapor pressure of ethanol is 400 mmHg at 63.5°C. Its molar heat of vaporization is 39.3 kJ/mol. What is vapor pressure of ethanol, in mmHg, at 34.9°C? A) 1,510 mmHg D) 0.0099 mmHg B) 100 mmHg E) 4.61 mmHg C) 200 mmHg Ans: B Category: Medium Section: 12.6 15. The molar enthalpy of vaporization of hexane (C6H14) is 28.9 kJ/mol, and its normal boiling point is 68.73°C. What is the vapor pressure of hexane at 25°C? A) 171 torr B) 4.44 torr C) 117 torr D) 3370 torr E) 759 torr Ans: A Category: Difficult Section: 12.6

II. Free Response.

1.Identify the dominant (strongest) type of intermolecular force present in NH3(l). Ans: hydrogen bonding Category: Medium Section: 12.2 2.Indicate all the types of intermolecular forces of attraction in CH3OH(l). Ans: hydrogen bonding and dispersion Category: Medium Section: 12.2 3.Given the following compound and its boiling point, identify whether it is polar or nonpolar: H2S, –60.7°C. Ans: polar Category: Medium Section: 12.2 4.Given that the heat of vaporization of diethyl ether is 26.0 kJ/mol and the vapor pressure of diethyl ether is 440 torr at 20.°C, calculate the normal boiling point of diethyl ether. Ans: 36°C (the actually boiling point is 34.6°C) Category: Medium Section: 12.6 5.Given that the heat of vaporization of mercury is 59.0 kJ/mol and the vapor pressure of mercury is 0.0017 torr at 25°C, calculate the normal boiling point of mercury. Ans: 380°C (the actually boiling point is 357°C) Category: Medium Section: 12.6...