The following bonus exercise contains 26 questions valued at 1/3 point/question

Transcription

1 Chem 121 Bonus Exercise Spring 2018 The following bonus exercise contains 26 questions valued at 1/3 point/question Name G = H T S PV = nrt P 1V 1 = P 2V 2 K = o C R =.0821 L atm/mole K P 1/T 1 = P 2/T 2 V 1/T 1 = V 2/T 2 1. Write the net ionic equation when solutions of NaNO3 and K3PO4 are mixed. If there is no reaction, write N.R. 2. Write the net ionic equation when solutions of Mg(NO3)2 and K3PO4 are mixed. 3. Write the net ionic equation when solutions of Ba()2 and Na2SO4 are mixed.

2 4. Please give the products of the following already balanced acid-base reaction. Ba()2 + H2SO4 5. Please give the products of the following already balanced acid-base reaction. Ba()2 + 2HCl 6. Please balance the following acid-base reaction. H2CO3 + Sr()2 SrCO3 + H2O 7. What is the oxidation state of sulfur in dihydrogen sulfide? a. +2 b. +1 c. 0 d. -1 e Which compound is oxidized and which is reduced in the following reaction? Twizzler + O2 CO2 + H2O Oxidized: Reduced: 9. Grain alcohol, aka ethanol (C2H6O) can be made by reacting ethylene (C2H4) with water in the presence of an acid catalyst. The balanced chemical equation for the reaction is C2H4 + H2O C2H6O How many grams of ethylene are needed to make 92.2 g of ethanol? a g b g c g d g e g

3 10. Referring to the previous question, if 92.2 g of ethanol are generated, how much water is consumed in the process? a g b g c g d g e g 11. Referring again to the generation of ethanol from ethylene and water, if 14.0 g of ethylene is reacted in excess water and 14.0 g of ethanol are generated, what is the percent yield?? a. 100 % b. 61 % c. 50 % d. 30 % e. 23 % 12. Reactions that proceed only with the release of free energy are termed a. Exothermic b. Endothermic c. Exergonic d. Endergonic 13. Is the dissolution of ammonium nitrate spontaneous at 10.0 o C? Please show your work NH 4NO 3 (s) NH 4 + (aq) + NO 3 - (aq) H = kj/mol, S = kj/mol K Spontaneous? 14. Which of the following does not influence the rate of a chemical reaction? a. The concentration of reactants b. The temperature of the system c. The activation energy for the reaction d. The presence of a catalyst e. N/A; all influence the rate of the reaction

4 15. Write the equilibrium expression for the following reaction CH 3CO 2H (aq) + Na (aq) CH 3CO 2Na (aq) + H 2O (aq) K = 16. What is the effect on the equilibrium concentration of acetic acid (CH 3CO 2H) in the preceding question if CH3CO2 - is added as potassium acetate? Hint: Viewing Na + and CH3CO2 - as separate ions above may help a. The acetic acid concentration will increase b. The acetic acid concentration will decrease c. The acetic acid concentration will increase and then decrease d. The acetic acid concentration will decrease and then increase e. The acetic acid concentration will not change 17. Which of the following has the highest boiling point? a. b. c. d. e. All of the above have nearly identical boiling points 18. Which of the following has the poorest solubility in water? a. b. c. d. e. All of the above are completely water soluble

5 19. Which of the following would you expect to have the highest boiling point? a. CH3CH2CH2CH2CH2CH2CH2CH2CH3 b. CH3CH2CH2CH2CH2CH2CH2CH2 c. CH2CH2CH2CH2CH2CH2CH2 d. CH3CH2CH2CH2CH2CH2CO2H e. CH3CH2CH2CH2CH2CH2CO2Na 20. Which of the following would you expect to have the greatest solubility in water? a. CH3CH2CH2CH2CH2CH2CH2CH2CH3 b. CH3CH2CH2CH2CH2CH2CH2CH2 c. CH2CH2CH2CH2CH2CH2CH2 d. CH3CH2CH2CH2CH2CH2CO2H e. CH3CH2CH2CH2CH2CH2CO2Na 21. Which of the following would you expect to exert the highest vapor pressure? a. CH3CH2CH2CH2CH2CH2CH2CH2CH3 b. CH3CH2CH2CH2CH2CH2CH2CH2 c. CH2CH2CH2CH2CH2CH2CH2 d. CH3CH2CH2CH2CH2CH2CO2H e. CH3CH2CH2CH2CH2CH2CO2Na Temperature ( o C) Vapor Pressure (mm Hg) What is the relative humidity on a 30 o C day if the gas pressure due to water is 23.8 mm Hg? Answer: 23. What is the dew point given the conditions in the preceding question? Answer:

6 24. Mechanical man closes his mechanical mouth and increases his lung volume from 2.5 L to 10.0 L. Since mechanical man s lung pressure was 1.0 atm when he began, what was his final lung pressure? a atm b. 4.0 atm c. 2.5 atm d. 1.0 atm e atm 25. Without opening his mechanical mouth, mechanical man reduces his lung volume to 0.25 L. What is the air pressure in his lungs before his mouth opens and air rushes out? a atm b. 4.0 atm c. 2.5 atm d. 1.0 atm e atm 26. What is the Celsius temperature in a closed rigid container containing only air, which had previously been at 2.0 atm and 25 o C, but is now at 0.50 atm? Celsius temperature of container =