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Name:_____________________________________________________ CHEMISTRY 1212 EXAM #1 VERSION 1 This exam is 8 pages long. Please read through all of the questions first and ask about anything you do not understand. You will have one hour and 15 minutes to complete this exam. Exams will be picked up at the end of the class period. No late exams will be accepted! You are allowed to use a calculator. If you do not have a calculator, setting up the problem correctly will gain you some points but you will not receive full credit for any question you do not answer completely. Included in this exam is a periodic table, which should be stapled to the back of the exam. CHEATING IS NOT ALLOWED. ANYONE CAUGHT CHEATING WILL RECEIVE A ZERO ON THIS EXAM. The exam is worth a total of 100 points. Each question is labeled with its exact point value. Be sure to answer all of the questions on the exam. Good Luck! T k m T k m P kC P P R T T H P P b b f f gas gas ^ 1 1 2 ln^2 Density of water is 1.00 g/mL and the normal boiling point of water 100C
Multiple Choice: Circle all correct answers! (3 points each) 1.)Which response includes all of the following substances in which dispersion forces are the most significant factors in determining boiling points, and no other substances? I) Cl 2 II) HF III) Ne IV) KNO 2 V) CCl 4 a.) I, III, and V b.) I, II, and III c.) II and IV d.) II and V e.) III, IV, and V 2.) Which response includes all of the following substances that exhibit hydrogen bonding and no others? I) H 2 II) CH 4 III) NH 3 IV) SiH 4 V) HF a.) II and V b.) I, II and III c.) III, IV and V d.) III and V e.) I, III and IV 3.) Which of the following boils at the highest temperature? a.) C 2 H 8 b.) C 3 H 8 c.) C 4 H 10 d.) C 5 H 12 e.) C 6 H 14 4.) Which one of the following statements is NOT applicable to molecular solids? a.) the units that occupy the lattice points are molecules b.) the binding forces in molecular solids are dispersion forces c.) molecular solids have relatively low melting points d.) molecular solids are usually excellent conductors of electricity e.) molecular solids re soft compared to covalent solids
9.) All of the following statements are false EXCEPT a.) the solubility of a gas in water increases with temperature b.) dissolving a solid in water is usually endothermic c.) when an equilibrium is established between molecules in a solid and a solution, the solution is said to be saturated d.) if a precipitate forms when a solution is cooled, the solution is supersaturated e.) network covalent solids are usually soluble in water 10.) The Henry’s Law constant for the solubility of carbon dioxide in water is 0. M/atm at 0.00C. if the pressure of CO 2 is 0.550 atm, what concentration of carbon dioxide can be dissolved in water at 0.00C?
(20 points) 11.) If 8.32 grams of methanol CH 3 OH are dissolved in 10.3 grams of water, what is the molality, mole fraction, % by mass of methanol and molarity of the solution? You can assume that the solution has the same density as that of pure water.
(10 points) 14.) Sucrose is a nonvolatile, non-ionizing solute in water. Determine the vapor pressure lowering, at 27C of a solution of 75.0 grams of sucrose C 12 H 22 O 11 , dissolved in 180. grams of water. The vapor pressure of pure water at 27C is 26.7 torr. Assume the solution is ideal. (10 points) 15.) The freezing point of a solution of 1.048 grams of an unknown non-electrolyte dissolved in 36.21 grams of benzene is 1.39C. Pure benzene freezes at 5.48C and its Kf value is 5.12 C/ m. What is the molecular weight of the compound?
(10 points) 16.) As solution is prepared by dissolving 5.00 grams of an unknown molecular solid in water to make 1.00L of solution. The osmotic pressure of the solution is 1.61 atm at 25C. What is the molar mass of the solute?
