practice+midterm+2 - Chem 1B W08 - McKeachie Practice...

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Chem 1B W08 - McKeachie Practice problems for midterm 2 1. What mass of water at 0 °C could be converted to ice at 0 °C simply from the vaporization of 26.0 g of liquid ammonia? ( H vap for NH 3 = 80.3 J mol -1 , H sub for H 2 O = 46.70 kJ mol -1 , H vap for H 2 O = 6020 J mol -1 ) 2. Of the following pairs, which would you expect to have a higher vapor pressure? Explain. a) Br 2 (s) vs I 2 (s) b) CaCl 2 (s) or Cl 2 (s) c) C 6 H 6 (l) or C 6 H 5 OH(l) d) CH 3 (CH 2 ) 4 CH 3 (l) or CH 3 (CH 2 ) 5 CH 3 (l) 3. One form of elemental tungsten crystallizes with a body-centered cubic unit cell. If incoming x-ray radiation with a wavelength of 0.204 nm is scattered in phase by the crystal at a 40 degree angle, what is the atomic radius of tungsten, in pm? 4. One form of crystalline silver uses the cubic-closest packed arrangement. If the edge length of the resulting unit cell is 0.40862 nm, calculate the density of silver, in g/cm 3 . 5. When an electron in excited molybdenum falls from the L to the K shell, an x-ray is emitted. These x-rays are diffracted at an angle of 7.75° by planes in a solid with a separation of 0.264 nm. What is the energy difference between the L and K shells in atomic molybdenum? 6. Determine the empirical formula and oxidation state of each ion for the following cubic unit cells. a) A unit cell containing I ions at the corners and a cesium ion in the center. b) A unit cell containing rhenium ions at the corners and oxide ions at the center of each edge. c) A unit cell containing oxide ions in the center of each face, a titanium ion in the center of the cell, and calcium ions at the corners. 7. Solid indium sulfide (In 2 S 3 ) can be produced by the reaction of elemental indium and sulfur. What mass of S is required to completely react with 1.000 g of In? Also, what mass of In 2 S 3 will be produced? 8.
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This note was uploaded on 02/09/2011 for the course CHEM 1B taught by Professor King during the Spring '08 term at UC Irvine.

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practice+midterm+2 - Chem 1B W08 - McKeachie Practice...

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