Bài tập hoá vô cơ: dung dịch

Chapter 11: Solution properties 11.1 How many grams of H2O must be used to dissolve 50.0 grams of sucrose to prepare a 1.25 m solution of sucrose, C12H22O11? 11.2 At 40°C, the vapor pressure of pure heptane is 92.0 torr and the vapor pressure of pure octane is 31.0 torr Consider a solution that contains 1.00 mole of heptane and 4.00 moles of octane Calculate the vapor pressure of each component and the total vapor pressure above the solution 11.3 When 15.0 grams of ethyl alcohol, C2H5OH, is dissolved in 750 grams of formic acid, the freezing point of the solution is 7.20°C The freezing point of pure formic acid is 8.40°C Evaluate Kf for formic acid 11.4 A 1.20-gram sample of an unknown covalent compound is dissolved in 50.0 grams of benzene.The solution freezes at 4.92°C Calculate the molecular weight of the compound 11.5 Either camphor (C10H16O, molecular weight of 152 g/mol) or naphthalene (C 10H8, molecular weight of 128 g/mol) can be used to make mothballs A 5.2-gram sample of mothballs was dissolved in 100 grams of ethyl alcohol, and the resulting solution had a boiling point of 78.90°C Were the mothballs made of camphor or naphthalene? Pure ethyl alcohol has a boiling point of 78.41°C; its Kb of 1.22°C/m 11.6 Lactic acid, C2H4(OH)COOH, is found in sour milk It is also formed in muscles during intense physical activity and is responsible for the pain felt during strenuous exercise It is a weak monoprotic acid and therefore a weak electrolyte The freezing point of a 0.0100 m aqueous solution of lactic acid is 0.0206°C Calculate (a) the i value and (b) the percent ionization in the solution 11.7 What osmotic pressure would the 1.25 m sucrose solution in Problem 11.1 exhibit at 25°C? The density of this solution is 1.34 g/mL 11.8 Pepsin is an enzyme present in the human digestive tract A solution of a 0.500gram sample of purified pepsin in 30.0 mL of aqueous solution exhibits an osmotic pressure of 8.92 torr at 27.0°C Estimate the molecular weight of pepsin Additional homework: Assignments in Chapter 11/ Chemistry (Steven S Zumdahl): 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81 Nguyen Tien Thao, Faculty of Chemistry, Hanoi College of Science, VNU 19 - Le Thanh Tong, Hoan Kiem, Hanoi, Vietnam Email: nguyentienthao@gmail.com