Section number. Dr. Rick Fletcher. Hour Exam 1 Chemistry 101 February 15, 2012

Transcription

1 NAME Section number Dr. Rick Fletcher Hour Exam 1 Chemistry 101 February 15, 2012 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. Maintain appropriate security over your exam. Do not let others see your answers. There is only one most correct response to each of the multiple choice questions. Choose the best answer. Each of the 25 questions is worth 4 points. Since the Scantron sheets will not be returned to you, please work through the entire exam and circle the best answer on this exam. Mark this exam as you work the problems then transfer the responses to the Scantron sheet all at one time. This is the best way to reduce errors. Use pencil on the Scantron sheets and make certain to fully erase any changes you make. Use this exam to check your answers on the key that will be posted online 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 ( Temp); T (K) = T ( C) ; T( F) = (1.8 X T( C)) + 32; 1 cal = J

2 1. A certain atom has a charge of +3 and has 33 protons and 42 neutrons in the nucleus. How many electrons does this atom possess? A) 33 B) 30 C) not enough information D) Which one of the following does not naturally exist as a diatomic molecule? A) hydrogen B) nitrogen C) fluorine D) helium 3. A certain neutral atom has 23 electrons orbiting its nucleus and 28 neutrons in the nucleus. How many protons must this atom have in the nucleus? A) 5 B) 51 C) 28 D) When a solid sample is converted into a liquid, the process is known as A) boiling. B) condensing. C) freezing. D) melting. 5. Titanium with a +4 charge and oxygen with a 2 charge form a compound. How many oxygen ions are required to neutralize the titanium ion? A) 4 B) 8 C) 2 D) 1 6. A laser beam travels a distance of 104,236 m in seconds. Which one of the following is the best expression (scientific notation) for the velocity of the beam? A) 3 x 10 8 m/s B) x 10 8 m/s C) 2.61 x10 8 m/s D) 2.6 x 10 8 m/s

3 7. A metal atom that loses an electron is known as a(n) A) anion. B) cation. C) sodium ion. D) onion. 8. Compound Z has 12 carbon atoms, 22 hydrogens and 3 oxygen atoms. What is its molecular formula? A) C 12 H 22 O 3 B) O 3 (C 6 H 11 ) 2 C) Ca 12 H 22 Ox 3 D) CHO 9. Which postulate in the atomic theory did the discovery of electrons contradict? A) atoms of the same element have the same properties B) chemical reactions are merely rearrangements of the atoms. C) atoms are indivisible D) chemical compounds are composed of atoms of different elements 10. How many significant figures does possess? A) 6 B) 1 C) 4 D) Which of the following measurements has the fewest number of significant figures? A) B) C) 1235 D) Which one of the following statements does not characterize all gases? A) They completely fill the container in which they are placed. B) They are invisible. C) Their fundamental particles move independently of one another. D) They have neither a definite shape nor a definite volume.

4 13. The following values were obtained by measuring the length of an object three separate times cm 5.4 cm cm The correct average of the measurements is A) 5.43 B) 5 C) 5.4 D) Which one of the following elemental symbols represents a subatomic particle composition of 80 neutrons, 56 protons, and 54 electrons? A) Ba B) Ba C) Xe D) Hg 15. The chemical bond that holds two carbon atoms together has a length of about 1.5Å, where 1 Å = 1 x m. Convert this value into inches. A) 3.8x10-12 in. B) 5.9x10-9 in. C) 1.5x10-8 in. D) 3.8x10-8 in. 16. A 10-g sample of an unknown metal displaces 0.88 ml of water. Determine the identity of the metal given the following: Li (d = 0.53 g/ml), Au (d = 19.3 g/ml), Al (d = 2.70 g/ml), and Pb (d = 11.3 g/ml). A) aluminum B) lead C) gold D) lithium 17. Your local power company has charged you $56.83, at a rate of $0.0264/Watt, for a month's use of electricity. How many watts (W) of electricity did you use? A) 215 W B) 1.50 W C) 56.9 W D) 2150 W

5 18. The distance from home plate to the center field fence is 404 feet. What is this distance in kilometers? A) 1.23x10 4 km B) km C) 1030 km D) 123 km 19. Given the isotopic notation for tungsten-184 ion ( W ), how many electrons are present? A) 68 B) 110 C) 80 D) A sample of mercury occupies a volume of 2.43 ml. If the density of mercury is 13.6 g/ml, what is the mass of this sample? A) g B) 5.60 g C) g D) 33.0 g 21. The mass number for three isotopes is known to be 126, 130, 128. Which atom has the largest number of protons? A) not enough information B) the 128 atom C) the 126 atom D) the 130 atom 22. Which ion has the largest number of electrons? A) Ga3+ B) Ca2+ C) 16 8 O2- D) Cl1-

6 23. Assuming all are measurements, which of the following is the best answer to (2.945)x(0.224)x( )? A) B) 7 C) D) The average for the three numbers below is read off of a calculator as What answer should you report, considering the proper number of significant figures? A) 24.9 B) 25 C) 24 D) While performing an experiment in lab, a student records a physical measurement as 4.45 in the lab notebook. This value is best described as A) accurate. B) imprecise. C) highly precise. D) meaningless. 26. Please indicate you are taking Version A of this exam by marking the A response on QUESTION 26 ON THE REVERSE SIDE OF THE SCANTRON SHEET.