ACS Gen Chem 2 Final Exam Study Guide

C - Answer- Where is the hydrophilic (attracted to water) region of the molecule? (A) Region 1 (B) Region 2 (C) Region 3 (D) The three regions are equally hydrophilic C - Answer- Which molecule is most soluble in water? D - Answer- A solution of NaCl in water has a concentration of 20.5% by mass. What is the molal concentration of the solution? Molar Mass NaCl = 58.44 g/mol (A) 0.205 m (B) 0.258 m (C) 3.51 m (D) 4.41 m B - Answer- What is the mole fraction of water in 200 g of 89% (by mass) ethanol, C2H5OH? Molar Mass C2H3OH = 46 g/mol (A) 0.11 (B) 0.24 (C) 0.32 (D) 0.76 D - Answer- A mixture of 100 g of K2Cr2O7 and 200 g of water is stirred at 60 degrees C until no more of the salt dissolves. The resulting solution is poured off into a separate beaker, leaving the undissolved solid behind. The solution is now colled to 20 degrees C. What mass of K2Cr2O7 crystallizes from the solution during the cooling? (A) 9 g (B) 18 g (C) 31 g (D) 62 g A - Answer- Carbonated beverages have a fizz because of gas dissolved in the solution. What increases the concentration of gas in a solution? (A) cooling the solution (B) heating the solution (C) increasing the volume of solution (D) decreasing the volume of solution D - Answer- When 100 g of an unknown compound was dissolved in 1.00 kg of water, the freezing point was lowered by 6.36 degrees C. What is the identity of this unknown compound? Kf for water = 1.86 degrees C/m (A) CsCl (B) KCl (C) LiF (D) NaCl A - Answer- Which 0.1 molal aqueous solution will have the lowest freezing point? (A) Al(NO3)3 (B) CaCl2 (C) C2H5OH (D) NaCl B - Answer