CHEM105 Practice Final Exam Key Fall 2013 Name Key Please ignore all point values on this Practice exam as they are all incorrect. Constants and equations: Speed of light: c = 2.997x10 8 ms -1 Plank’s constant: h=6.626x10 -34 J ∙ s 1 J = 1 kg ∙ m 2 ∙ s -2 charge of an e - : e = 1.602x10 -19 C mass of e - : m e =9.11x10 -31 kg mass of p + : m p =1.67x10 -27 kg Avogadro’s constant: N A = 6.022x10 23 mol -1 DeBroglie Relation: v ( ) ( ) c = ∙ R=0.08206 L atm mol -1 K -1 = 8.314 J mol -1 K -1 √
CHEM105 Practice Final Exam Key Fall 2013 Multiple Choice: 1. The degree of agreement among several measurements of the same quantity is called __________. It reflects the reproducibility of a given type of measurement. a) accuracy b) error c) precision d) significance e) certainty 2. A species with 12 protons and 10 electrons is – 3. Which of the following atomic symbols is incorrect? a) 146Cb) 3717Clc) 3215Pd) 3919Ke) 148N4. Consider the element indium, atomic number 49, atomic mass 114.8 g. The nucleus of an atom of indium-112 contains 5. Phosphorus has the molecular formula P4,and sulfur has the molecular formula S8. How many grams of phosphorus contain the same number of molecules as 7.88 g of sulfur? 6. You have exposed electrodes of a light bulb in a solution of H2SO4such that the light bulb is on. You add a dilute solution and the bulb grows dim. Which of the following could be in the solution? a) Ba(OH)b) NaNOc) K2SOd) Cu(NO3)e) none of these 2 3 4 2
CHEM105 Practice Final Exam Key Fall 2013 7) A reaction occurs between sodium carbonate and hydrochloric acid producing sodium chloride, carbon dioxide, and water. The correct set of coefficients, respectively, for the balanced reaction is: 3 4 10 5 5 5 1 1 8. All of the following reactions 2Al(s) + 3Br2(l) 2AlBr3(s2Ag2O(s) 4Ag(s) + O2(gCH4(l) + 2O2(g) CO2(g) + 2H2O(gcan be classified as ) ) ) Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and 1 atm pressure. 9. Which gas has the highest density? 2 4 3 10. For which gas do the molecules have the smallest average kinetic energy? a) He b) Clc) CHd) NHe) all gases the same 2 4 3
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