NAME Section number. Dr. Rick Fletcher

Transcription

1 NAME Section number Dr. Rick Fletcher Homework 1 Chemistry 101 September 19, 2008 There is one most correct response to each of the multiple choice questions. Choose the best answer. Each of the twenty-five questions is worth 1 point. Please work through the entire exam and circle the best answer on this exam paper. Bring this completed exam into class on Friday and transfer the responses to the Scantron sheet all at one time. We will do this at the beginning of class period on Friday, September 19. Keep this completed exam and use it to check your answers on the key that will be posted online after class on Friday. Clearly print your name in the name section of the Scantron answer sheet. Clearly place your student ID number in the SUBJECT section of the Scantron sheet cm = 1 in 454 g = 1 lb 946 ml = 1 qt 5280 ft = 1 mile 16 oz = 1 lb 4 qt = 1 gal heat = (sp. Ht.) X (mass) X (ΔTemp) T (K) = T ( C) T( F) = (1.8 X T( C)) cal = J 1 cm 3 = 1 ml Page 1

2 1. It is recommended that a football be inflated to 9.0 psi (pounds per square inch). Convert this pressure into mmhg (millimeters of mercury) using the following information. 1 atm = 14.7 psi and 1 atm = 760 mmhg A) 470 mmhg B) 8.1x10-4 mmhg C) 0.2 mmhg D) 1.0x10 5 mmhg 2. A major league pitcher can throw a fastball at 43 m/sec. How fast is his fastball in miles per hour? A) 75 mph B) 96 mph C) 89 mph D) 62 mph 3. Which postulate in the atomic theory did the discovery of electrons contradict? A) chemical compounds are composed of atoms of different elements B) chemical reactions are merely rearrangements of the atoms. C) atoms of the same element have the same properties D) atoms are indivisible 4. A 25-g sample of zinc absorbs 500 J of energy. If the temperature of the sample increases by 51 o C, what is the specific heat for zinc? A) J/g o C B) 0.39 J/g o C C) 250 J/g o C D) 2.5 J/g o C 5. Given the isotopic notation for tungsten-184 ion ( W + ), how many neutrons are present? A) 68 B) 74 C) 110 D) 80 Page 2

3 6. The speed of light in a vacuum in about m/sec. This number in scientific notation can be expressed as A) 3.0x10 8 m/sec B) 2.998x10 8 m/sec C) x10 9 m/sec D) Both b and d 7. Which one of the following does not naturally exist as a diatomic molecule? A) hydrogen B) nitrogen C) fluorine D) helium 8. The base unit in the metric system for length is which one of the following? A) kilograms B) centimeters C) feet D) meters 9. Given the isotopic notation for tungsten-184 ion ( W + ), how many electrons are present? A) 68 B) 110 C) 80 D) Using the appropriate number of significant figures, calculate the answer to the following mathematical equation; (10.0 x 8.606) - ( / ). A) 2000 B) 1993 C) 2014 D) Titanium is obtained from the ore ilmenite. This compound contains 3 oxygen atoms and 1 iron atom for each titanium atom. What is the molecular formula? A) Fe 3 TiO B) FeTiO 3 C) 3 FeTiO D) FeTi. 3O Page 3

4 12. The temperature at which a solid is converted into a liquid is most accurately called the A) condensation point. B) melting point. C) boiling point. D) freezing point. 13. A certain neutral atom has 23 electrons surrounding its nucleus and 28 neutrons in the nucleus. How many protons must this atom have in the nucleus? A) 23 B) 51 C) 5 D) Which of the following contains the largest number of protons? A) 107 Ag B) 128 Te C) 121 Sb D) 127 I 15. A 50-g sample of ethanol is added to 100 g of kerosene (d = 0.82 g/ml). If the final volume of the mixture is 185 ml, what is the density of ethanol assuming additive volumes? A) 0.49 g/ml B) 0.79 g/ml C) 0.27 g/ml D) 0.59 g/ml 16. How many significant figures does possess? A) 3 B) 4 C) 2 D) A nonmetal atom that gains an electron is known as a(n) A) cation. B) onion. C) sodium ion. D) anion. Page 4

5 18. A sample of brass, a metal alloy, would be classified as A) a heterogeneous mixture. B) a pure substance. C) a compound. D) a homogeneous mixture. 19. A change, whether physical or chemical, that absorbs heat from the surrounding is A) an exothermic change. B) an ectodermic change. C) an endothermic change. D) an exotic change. 20. A rectangular swimming pool has the following dimensions (l x w x h), 5.3 m x 3.6 m x 2.5 m. What is the volume of the pool in milliliters? A) 4800 ml B) 4.8x10-5 ml C) 4.8x10 7 ml D) 48 ml 21. Which one of the following substances is not an element? A) CCl 4 B) Silicon C) Argon D) Iron 22. The length of a single bond joining two carbon atoms together is approximately m. This number in scientific notation is expressed as A) 1.5x10 10 m B) 1.5x10-10 m C) 1.50x10-10 m D) 1.5x10-9 m 23. The melting point for an unknown compound is 408 K. What is its melting point in o C? A) 135 B) 35 C) 681 D) 101 Page 5

6 24. A sample of propane (25 g) is burned in 86 g of oxygen in a chemical reaction to produce water and carbon dioxide (CO 2 ). If 78 g of CO 2 is formed, how much water was also produced? A) 33 g B) 30 g C) 103 g D) not enough information 25. Which one of the following elemental symbols represents a subatomic particle composition of 80 neutrons, 56 protons, and 54 electrons? A) Xe B) Ba + C) Ba D) Hg Page 6