Assignment title: Information


Question 1 (based on Topic 5 - chapter 6 of text) (25 marks) Hydrogen iodide gas, HI, forms when hydrogen, H2 and iodine, I2 react: H for the reaction is + 26.5 kJ/mole. a) Write a balanced equation for the reaction. (3 marks) b) Is this reaction endothermic or exothermic? Explain. (4 marks) c) Write an expression for the equilibrium constant for this reaction. (4 marks) d) Given that the value of the equilibrium constant is 48 at 720 K; can you predict if this reaction is fast or slow? Explain (4 marks) e) Explain the effect on equilibrium of the formation of HI form H2 reaction with I2 by; i. Increasing temperature (2 marks) ii. Increasing pressure by decreasing the volume (2 marks) iii. Decreasing concentration of hydrogen (2 marks) iv. Increasing the concentration of iodine (2 marks) v. Adding a catalyst (2 marks) Question 2 (based on Topic 5 - chapter 5 of text) (25 marks) Sugar cane may be used as a renewable source of ethanol, C2H6O, via the conversion of sucrose, C12H22O11, according to the following unbalanced equation: 𝐢𝐢12𝐻𝐻22𝑂𝑂11(𝑠𝑠) + 𝐻𝐻2𝑂𝑂(𝑙𝑙)β†’ 𝐢𝐢2𝐻𝐻5𝑂𝑂𝐻𝐻(𝑙𝑙) + 𝐢𝐢𝑂𝑂2(𝑔𝑔) a) Explain why this is a chemical reaction. (2 marks) b) Balance the equation for this reaction. c) How many grams of ethanol are formed from the complete conversion of 0.750 moles of sucrose? (5 marks) d) How many grams of ethanol are formed from the complete conversion of 37.5g of sucrose? (5 marks) e) What is the theoretical yield of ethanol in grams for the complete conversion of 57.5 g of sucrose? (5 marks) f) If 25.0 g of ethanol actually forms, what is the percentage yield of ethanol for the reaction of 5.75 g of sucrose? (4 marks) Question 3 (based on Topic 6 - chapter 7 & 8 of text) (25 marks) a) A helium, He, balloon has a volume of 3.50 L at 22.0 oC and 1.14 atm. What is its volume if the temperature is increased to 30.0 oC and the pressure increased to 1.20 atm? (7 marks) b) Nalorphine, a relative of morphine, is used to combat withdrawal symptoms in heroin users. How many mL of a 0.80 % m/v nalorphine solution must be injected to obtain a dose of 2.5 mg? (6 marks) c) What characteristic must a compound have to experience the following intermolecular forces? i. London Dispersion Forces (2 marks) ii. Dipole-dipole forces (2 marks) iii. Hydrogen bonding (2 marks) d) Identify the predominant intermolecular forces in dimethyl ether (CH3OCH3) and ethanol (C2H5OH) and predict which will have the higher boiling point. (6 marks) Question 4 (based on Topic 7 - chapter 8 of text) (25 marks) a) Describe how you would prepare 750 mL of a 0.250 M solution of nitric acid, HNO3, available commercially at a concentration of 16.0 M. (10 marks; Note: 6 marks for calculation, 4 marks for description) b) Describe how you would prepare 250.0 mL of a 0.050 M sucrose solution given that the sucrose is supplied as a solid. Molar mass of sucrose is 342.2965 gmol-1 (10 marks; Note: 6 marks for calculation, 4 marks for description) c) Which lowers the freezing point of 2.0 kg of water more, 0.20 moles of NaOH or 0.20 moles of Ba(OH)2? Explain your answer.