Chem 122 Final Exam Questions for Saturday Morning Review Spring 2022 R Hatfield L Schroeder and E Stec 1 a What is the pH of a buffer with 0 60 M NaH2PO4 and 0 40 M Na2HPO4 7 02 b What is the change in pH when 5 0 ml of 1 0 M NaOH is added to 100 0 ml of buffer containing 0 60 M NaH2PO4 and 0 40 M Na2HPO4 7 11 change 0 09 Note Ka1 7 2 x 10 3 2 This titration represents an unknown weak acid being titrated with potassium hydroxide a Is the pH at the equivalence point equal to 7 greater than 7 or less than 7 Explain b If the equivalence point is at 20 ml estimate the pKa of the weak acid Ka3 4 2 x 10 13 Ka2 6 3 x 10 8 3 The molar solubility of silver phosphate in pure water is 1 6 x 10 5 M Determine the Ksp of silver phosphate 1 8 x 10 18 4 Lead II sulfate PbSO4 is a key component in lead acid car batteries Its solubility in water at 25 C is 4 25x10 3 g 100 mL solution What is the Ksp of PbSO4 1 96 x 10 8 5 The Ksp of lead II fluoride is 3 3 x 10 8 Determine the molar solubility S of lead II fluoride in a pure water 2 0 x 10 3 M b 0 10 M Pb NO3 2 2 9 x 10 4 M c 0 10 M NaF 3 3 x 10 6 M 6 For each of these slightly soluble salts determine if adding a solution of magnesium chloride or nitric acid would increase decrease or not change the solubility slightly soluble salt AgCl Mg3 PO4 2 CaF2 MgCl2 aq added HNO3 aq added 7 Is a buffer formed when equal volumes of the following solutions are mixed together A 0 1 M HCl and 0 2 M HNO2 B 0 1 M NaOH and 0 2 M HNO2 C 0 1 M NaCl and 0 2 M HNO2 D 0 1 M HCl and 0 2 M NH3 E 0 1 M NaOH and 0 1 M NH3 F 0 1 M NaOH and 0 2 M NH G 0 1 M NaOH and 0 2 M HCl 8 Given the following reaction 2 NO g 5 H2 g 2 NH3 g 2 H2O g a Assign oxidation states to each element in the reaction shown above b Identify the oxidizing agent c Identify the reducing agent d Which element was oxidized e Which element was reduced 9 A 50 0 mL sample of 0 102 M potassium sulfate solution is mixed with 30 0 mL of 0 900 M barium nitrate solution A solid product is collected dried and found to have a mass of 2 95 g a Predict the products and write a balanced equation for this reaction b Write a balanced net ionic reaction equation c Determine the limiting reactant d Determine the theoretical yield of solid product 1 19 g e Determine the percent yield 40 3 10 Given the following solutions Na2CO3 aq KOH aq HBr aq Ba C2H3O2 2 aq i Write a balanced molecular reaction that fulfills the goal of the question States must be included ii Write the net ionic equation for each reaction you wrote a Give an example of a gas forming reaction b Give an example of an acid base reaction c Give an example of a precipitation reaction 11 48 0 grams of ethylene glycol 62 07 g mol is dissolved in 500 0 grams of water The vapor pressure of water at 32 oC is 35 7 mmHg What is the vapor pressure of the water above the solution that was prepared Ethylene glycol is a non electrolyte and nonvolatile 34 7 mmHg 12 As aqueous solution containing 1 00 g of bovine insulin a protein non electrolyte per liter has an osmotic pressure of 3 1 mmHg at 25 oC Calculate the molar mass of bovine insulin 6 0x103 g mol 13 Consider the reaction C s H O g CO g H g Predict whether the reaction will shift left shift right or remain unchanged after each disturbance a C is added to the reaction mixture b H2O is condensed and removed from the reaction mixture c CO is added to the reaction mixture d H2 is removed from the reaction mixture e The volume of the reaction contain is doubled chloride and 725 mL of oxygen gas at 130 and 751 torr 1 76 g 14 How many grams of potassium chlorate 122 55 g mol decompose to form potassium 15 An 9 50 L tire contains 16 0 g of oxygen gas at a temperature of 325 K What is the pressure in atm of the gas in the tire 1 40 atm 16 Determine the pH at the equivalence point when a 30 mL sample of 0 20 M acetic acid is titrated with 0 20 M potassium hydroxide The 2 of acetic acid is 1 8 1067 8 87 titrated with 0 20 M hydrobromic acid The 8 of ammonia is 1 76 1067 5 12 17 Determine the pH at the equivalence point when a 30 mL sample of 0 20 M ammonia is 18 A sample of an unknown gas effuses in 11 1 min An equal volume of H2 in the same apparatus under the same conditions effuses in 2 42 min What is the molar mass of the unknown gas 42 0 g mol