kamalska (mk23835) – HW01 – Quigley – (104001) 1 This print-out should have 30 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points A crystal of dry ice (solid CO 2 ) consists of molecules of CO 2 arranged at orderly po- sitions in a crystal lattice. The molecules are bonded intramolecularly by covalent C O bonds, and are held together in the crystal by weak intermolecular forces between the CO 2 molecules. This is an example of 1. an ionic crystal. 2. a molecular crystal. 3. a covalent crystal. 4. an amorphous substance. 5. a metallic crystal. 002 10.0 points Surface tension describes 1. adhesive forces between molecules. 2. capillary action. 3. the forces of attraction between the sur- face of a liquid and the air above it. 4. the inward forces that must be overcome in order to expand the surface area of a liq- uid. 5. the resistance to flow of a liquid. 6. the forces of attraction between sur- face molecules of a solvent and the solute molecules. 003Carbon in the form of graphite (sp2hybridiza-tion) is a reasonable electrical conductor alongtwo crystal directions and a poor conductoralong a third. Carbon in the form of diamond(sp3hybridization) is an excellent insulatorin all crystal directions. Which of the follow-ing best explains this difference based on the 10.0 points Rank the gas molecules CH 3 F , C 2 H 6 , H 2 O , H 2 , He in terms of increasing non-ideality based upon intermolecular interactions. 1. H 2 O , CH 3 F , C 2 H 6 , H 2 , He 2. C 2 H 6 , H 2 O , CH 3 F , He , H 2 3. H 2 , He , CH 3 F , H 2 O , C 2 H 6 4. None of these is correct. 5. He , H 2 , C 2 H 6 , CH 3 F , H 2 O 004 10.0 points The phase diagram for a pure substance is given below. Solid Liquid Vapor 50 100 150 200 250 300 100 200 300 400 Temperature, K Pressure, atm At 100 atm and 250 K, the substance exists as 1. both vapor and solid in equilibrium. 2. vapor. 3. solid. 4. liquid. 5. both vapor and liquid in equilibrium. 005 10.0 points
kamalska (mk23835) – HW01 – Quigley – (104001) 2 bonding between the carbons?
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- Crystal, Intermolecular force, O H C H H C H O C H H C H H C H H C H H C H H C H H C H H C H H C H H C H H C H H C H H C H H C H H C H H C H H O C H H O