Test 4 Name Chemistry 10 Dr Kline 27 May 2004 Row Seat Lab 8 00 10 30 This test consists of a combination of multiple choice and other questions There should be a total of 25 questions on 6 pages plus a page with equations and other information please check to make sure that they are all here You may use the equation information sheet and any periodic table provided last page Do not use your own tables scratch paper or other information Do not share your calculator Please turn off all cell phones pagers and other communication devices if they make noise they will be confiscated Shared calculators will be confiscated It is OK to tear off the periodic table page Multiple Choice Questions Each of the following 20 questions is worth three points for a total of 60 points There is only one correct answer for each question unless it is stated otherwise for a given question Answer each question by circling the letter s corresponding to the correct choice s in other words if there is more than one correct answer circle all of the correct ones It is not necessary to show work for these questions however you may write on the exam 1 A transition from the solid phase directly to the gas phase is known as a sublimation b boiling c deposition d evaporation e melting 2 What kinds of intermolecular forces are present in the molecule below If more than one kind is present circle all of them that are present O H H a b c d 3 hydrogen bonding dispersion forces dipole dipole interactions none of the above H H H C C C H H H O H H O H H C C H H O H Circle the compound that is expected to have the lowest vapor pressure H F C H F Br H 5 H H Circle the compound that is expected to have the higher boiling point H 4 C C C H Br Cl H C H Cl H I C I H Circle the compound that is expected to have the higher boiling point H H H C C H H O H H H H C C H H S H Chem 10 Test 4B page 1 of 4 6 Circle all of the compounds in the group below that are capable of intermolecular dipole dipole interactions More than one is possible H F C H H F H C H H O C H H H I C H H I H C N H H H 7 Which of the following has the highest melting point a KI b CI4 c Kr d I2 8 What happens when additional solid solute is added to a unsaturated solution a It dissolves until its solubility limit is reached b It doesn t dissolve c It doesn t dissolve and additional solute comes out of solution 9 In which of the following solvents would sucrose a polar substance be expected to be soluble More than one answer may be correct a hexane C6H14 b water c ethanol structure on the left in problem 5 10 The solubility of carbon dioxide in water is about 1 5 g per 100 g of water at 30 C Which of the following would cause the solubility of carbon dioxide in water to increase a a decrease in temperature b an increase in the pressure of nitrogen gas over the solution c an increase in the pressure of carbon dioxide gas over the solution d none would 11 Which of the following has the lower freezing point a pure water b 0 10 M NaCl aq c neither because they both have the same freezing point d it is impossible to tell 12 Two aqueous solutions of glucose C6H12O6 are placed in a U tube A semi permeable membrane at the bottom of the tube separates the two solutions What happens More than one of the listed things might happen a glucose molecules move from right to left through the membrane b water molecules moves from left to right through the membrane c the liquid level on the right side decreases d nothing happens 13 How a b c d e many grams of NaOH are present in 100 mL of 0 10 M NaOH aq 0 010 g 0 10 g 40 g 4 0 g 0 40 g Chem 10 Test 4B page 2 of 4 14 What volume of 2 00 M KCl is needed to prepare 500 mL of 0 100 M KCl a 25 0 mL b 40 0 mL c 50 0 mL d 100 mL e 250 mL 15 What is the concentration of hydroxide ion OH in 0 20 M Ba OH 2 a 0 10 M b 0 20 M c 0 40 M d 0 40 M 16 What is the pH of 0 10 M HC2H3O2 at 25 C a pH 7 b pH 7 c pH 7 17 Which of the following corresponds to the most basic solution a pH 4 00 b OH 1 0 x 10 3 M c H 1 0 x 10 8 M 18 Which of the following solutions would have H 0 10 M More than one answer may be correct a 0 10 M HNO2 b 0 10 M HNO3 c 0 10 M H2SO4 19 Suppose that 100 mL of 0 20 M KOH is combined with 125 mL of 0 10 M HCl Is the resulting solution acidic basic or neutral a acidic b basic c neutral 20 Which of the following aqueous mixtures is are buffer solutions More than one answer may be correct a HI and KI b HF and KF c HClO and NaCl d none of them Chem 10 Test 4B page 3 of 4 Problems and Questions Each of the following is worth the indicated number of points for a total of 40 points Please show work with units to receive credit unless instructed otherwise Also be sure to provide all of the information requested for each question 21 9 points An aqueous solution is prepared by dissolving 17 5 g KNO3 in 125 mL of water Note that the density of water is 1 00 g mL Assume that the density of the solution is 1 12 g mL a What is the percent by mass of the KNO3 in the solution b What is the molarity of the KNO3 in the solution 22 6 points Write balanced reaction equations with state labels to show why each of the following is true a Hydrocyanic acid HCN is a weak acid b Chlorite ion ClO2 is a weak base 23 8 points Calculate the OH H and pH of 0 0082 M KOH at 25 C Clearly show all equations used and remember that you must show work or a set up for any mathematical process that you cannot do in your head 24 8 points How many grams of aluminum are needed to react with 85 0 mL of 4 0 M HBr by the reaction 2Al s 6HBr aq …