CHEM 112 Prac Exam 1

CHEM 112 Prac Exam 1 - 1.. The mass percent of acetone in a...

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Unformatted text preview: 1.. The mass percent of acetone in a solution prepared by mixing 89.6 g acetone (C3H60) and 72.1 g of H20 is: 1} 44.6% 2] 80.6% 3] 55.4% 4} 13.9% 5] none ofthese 2. Which substance Eisted beiow would be most likely to dissolve in C6H6? i] NH3 2] 12 3] HCl 4] CHzClz 5} none would dissolve 3. A gas dissolves in water, forming a saturated solution and giving off heat. When the solution is heated: 1. the solubility of the gas does not change. 2. the solubility of the gas increases. 3. the solubility of the gas decreases. 4. the dissolved gas causes the water to boil at a lower temperature. 5. no general prediction can be made about the solubility change. 4. A solution of a noneiectrolyte dissolved. in carbon tetrachloride has a boiling point that is 430°C higher than the solvent. What is the moiality of the solute given kb is 5.030C/m? l] 8.55 m 2] 0.855 in 3} li.2 in 4] 0.895111 5] none ofthese 5. Which aqueous soiution has the iowest freezing point? i} 0.20 M ethanol-(a nonelectrolyte) 2] 0.40 M NaNO3 3} 0.20 M CaBr2 4} 0.10 M KCl 5} 31!. have the same freezing point [H2]4 4 is for which reaction listed below? lH 20l 6. The Kc expression ll 2 H2(g) t 02(g) *3 2 H20(g) 2l F6(S)+4 H20(s) $2 1363048) +4H2(g) 3] 4 H20(g) e 4 H2(g) + 2 02(g) 4} 2Na(s) + 21420(g) e2 2Na0H(aq)+ H2(g) 5] none of these 7. For the reaction 2 H20 (g) $1 2 l~lgO(g) + 02(g) the reiation between .Kp and KC is: {- Ifp 2K0 2. KDZKC(RT) 3- Kp: c(RT)3 4' K02 C(RT)-3 5. Kmec(RT)-] 8. The reaction 2N‘O(g) + 2C0(g) @- N2(g) + 2C02(g) was allowed to reach equilibrium. Additional N0 gas was then injected into the reaction chamber and equilibrium was restored. Choose the correct statement below. 1. All concentrations remain the same. 2. A new equilibrium is obtained such that [N2] decreases. 3. The value C)ch increases. 4. A new equilibrium is obtained such that [CO} decreases. 5. A new equilibrium is obtained such that both {CO} and [NZ] decrease. 9. Calculate the molarity of glucose (C6H1206) in a soiution in which 10.0 g of glucose is dissolved. in water and diluted to a final volume of 200 mL. l0. Water has a kf of 1.860Cfrn and a freezing point of 0°C. What is the freezing point 019:: soiution made by dissolving 320 gram of CH30H (a nonelectrolyte) in 100 grains of water? 'i i . Calculate the osmotic pressure of an electrolyte solution that contains 0.0010 mole of KBr and 0.00 i 0 mole of 8302 per iiter of soiution at 298 K. (R2 0.0821 L atria/mole K) 12. At high temperature, the following gas phase equilibrium is established: N205 $2 N20 + 202. Initially, 1.00 mole ongos is sealed into a 0.182 L flask. Afier equilibrium, the N20 concentration is 0.50 M. Calculate KC . l3. One (1.00) mole ofNO is placed in a 5.00 L container at 750°C. lfKC m 2.06 x 10“2 at this temperature for 2 N0(g) :2 N2(g) + 02(g) what is the equilibrium concentration ofNO(g)? a. (5 pts) Setup an iCe table. in. (2 pts) Plug the e “values” from the iCe chart into the Kc expression, but do not solve. c. (2 pis) Solving the KC expression using the quadratic formula yields two answers mathematically, 2.50 x 10—2 and W290 x 10—2, calculate the concentration of NO(g). 14. The concentration of02'in biood is LO x 10"2 mola]. At 37°C (body temperature), Henry‘s law constant for oxygen is 1.8 x 10"3 molaI/atrn. What is the apparent pressure 01°02 (in atmospheres) in contact with the blood? 15. At a particular temperature, the solubility of lead bromide, .PbBr2 in pure water is 2.2 x :0'2 M; The value ofKSp is: 16. Calculate the solubifity ong] in a 0.100 M Nal solution at 25°C. The Ksp for Agl is 8.50 x 10"” at 25°C. ...
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This note was uploaded on 06/14/2011 for the course CHEM 112 taught by Professor Chen during the Spring '09 term at South Carolina.

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CHEM 112 Prac Exam 1 - 1.. The mass percent of acetone in a...

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