MCQs for Exam 2 - Foundations of Chemistry I | CHEM 184, Exams of Chemistry

Download MCQs for Exam 2 - Foundations of Chemistry I | CHEM 184 and more Exams Chemistry in PDF only on Docsity! CHEM 184 – Fall, 2010 Hour Exam 2 (Red) October 7, 2010 Instructions: Your scantron answer sheet must show your NAME, STUDENT 7-DIGIT KUID NUMBER, and LAB SECTION. (Begin these entries at the LEFT end of the space provided.) In answering the questions, be careful to fill in the corresponding circles on the answer sheet according to the number of the question on the exam. USE A SOFT (No. 2) PENCIL. Note that a periodic table of the elements is attached at the end of the exam. Useful information: Avogadro’s constant NA = 6.022 x 1023 mol-1 Planck’s constant h = 6.626 x 1034 Js Speed of light c = 3.00 x 108 m/s Rydberg constant RH = 2.18 x 1018 J H-atom energy levels ) n 1 (RE 2Hn  _________________________________________________________________________________ 1. A 75 kg person drinks 350 g of milk, which has a "caloric" value of approximately 3.0 kJ/g. If only 18% of the energy in milk is converted to mechanical work, how high (in meters) can the person climb based on this energy intake? [Hint: The work done in ascending is given by mgh, where m is the mass (in kilograms), g the gravitational acceleration (9.8 m/s2), and h the height (in meters.)] A. 170 B. 260 C. 350 D. 450 E. 560 2. Which answer lists all of the following processes that are exothermic, and none that are endothermic? 1. boiling of water 2. freezing of water 3. condensation of steam 4. melting of ice A. 1 & 2 B. 2 & 3 C. 1 & 4 D. 2, 3 & 4 E. 2 & 4 3. Given the thermochemical equation 1 H2(g) + Cl2(g)  2HCl(g) + 184.6 kJ calculate the enthalpy change, H, for the reaction HCl(g)  ½ H2(g) + ½ Cl2(g) A. –184.6 kJ B. –92.3 kJ C. 0 kJ D. 92.3 kJ E. 184.6 kJ 4. The combustion of butane produces heat according to the equation 2C4H10(g) + 13O2(g)  8CO2(g) + 10H2O(l) Horxn = 5,314 kJ How much heat is generated by the combustion of 80.0 g of butane? A. 1,370 kJ B. 2,510 kJ C. 3,660 kJ D. 4,800 kJ E. 5,940 kJ 5. Given the following data: C(s) + ½ O2(g)  CO(g) H = 110.5 kJ C(s) + O2(g)  CO2(g) H = 393.5 kJ What is H for the reaction CO2 (g)  CO(g) + ½ O2(g) A. –504.0 kJ B. –283.0 kJ C. +110.5 kJ D. +283.0 kJ E. +504.0 kJ 6. Rank the following regions of the electromagnetic spectrum in order of decreasing energy. X-rays, microwaves, infrared, ultraviolet A. X-rays, ultraviolet, infrared, microwaves B. microwaves, ultraviolet, infrared, X-rays C. microwaves, infrared, ultraviolet, X-rays D. X-rays, microwaves, infrared, ultraviolet E. infrared, ultraviolet, X-rays, microwaves 7. What is the wavelength (in centimeters) of light having a frequency of 1.5 x 1020 Hz? A. 2.0 x 1010 cm B. 2.0 x 108 cm C. 5.0 x 109 cm D. 5.0 x 1011 cm E. 4.5 x 1028 cm 8. What is the energy of a mole of photons associated with light of wavelength 930 nm? A. 299 kJ B. 179 kJ C. 150 kJ D. 129 kJ E. 105 kJ 9. The work function, W, of magnesium metal is 5.90 × 1019 J. Calculate the maximum wavelength of light required to release electrons from the metal. A. 195 nm B. 248 nm C. 337 nm D. 432 nm E. 581 nm 2