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Unformatted text preview: Chem 103 Practice Questions Chapter 2 1. Indicate the number of protons, neutrons, and electrons in a neutral atom of a. 79Br b. 119Sn A 2. Give the complete symbol ( Z X ) for an atom of a. iron with 32 neutrons b. sulfur with 17 neutrons 3. Thallium has two stable isotopes, 203Tl and 205Tl. Given that the average atomic mass of thallium is 204.4, which isotope is the more abundant of the two? 4. Bromine has two naturally occurring isotopes, 79Br and 81Br, with masses of 78.918336 and 80.916289, and abundances of 50.69% and 49.31%, respectively. Calculate the average atomic mass of bromine. 5. You have 1.0g samples of Ti, Cr, Fe, Ni, and Zn. Which sample contains the largest number of atoms? 6. A reaction produces 136 grams of copper metal. How many moles is this? 7. The Hope diamond weighs 45.52 carats. Given that a carat is defined as a unit of mass equal to 200 mg, how many moles of carbon are in the Hope diamond? How many atoms of carbon? 8. For each element below, put an X in the box for each classification into which the element falls. Br Mg Ar Cu main group element transition element metal nonmetal alkali metal alkaline earth metal halogen noble gas Answers 1. a. 35 p, 44 n, 35 e; b. 50 p, 69 n, 50 e 58 33 2. a. 26 Fe , b. 16 S 3. 205Tl 4. 79.90 u 5. Ti 6. 2.14 mol 7. 0.7580 mol, 4.5651023 atoms 8. Br Mg main group element X X transition element metal X nonmetal X alkali metal alkaline earth metal X halogen X noble gas Ar X X X Cu X X ...
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- Spring '09