CHEM 150 Exam 2. Name Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.

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1 CHEM 150 Exam 2 Name Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. Formic acid, HCOOH, is what causes the sting of bee stings. What is the formula weight of formic acid? a. 29 amu b. 46 amu c. 50 amu d. 58 amu 2. What is the weight of 300. moles of KCl? a amu b g c amu d g 3. The balanced equation 2H 2 + O 2 2H 2 O means which of the following? a. two grams of hydrogen react with one gram of oxygen to form two grams of water b. two moles of hydrogen react with one mole of oxygen to form two mole of water c. the equation represents both (a) and (b) d. the equation represents neither (a) nor (b) 4. What do we call the chemicals which appear to the right of the arrow in a balanced chemical equation? a. products b. reactants c. reagents d. none of the above 5. Which of the following is the correctly balanced equation for the complete combustion of methane, CH 4? a. CH 4 (g) + O 2 (g) H 2 O(g) + CO(g) b. CH 4 (g) + O 2 (g) H 2 O(g) + CO 2 (g) c. 2CH 4 (g) + 5O 2 (g) 4H 2 O(g) + 2CO(g) d. CH 4 (g) + 2O 2 (g) 2H 2 O(g) + CO 2 (g) 6. A classic method for generating molecular oxygen is the decomposition of potassium chlorate, KClO 3. The other product of this reaction is potassium chloride. Which of the following is the correctly balanced chemical equation for this reaction? a. KClO 3 (s) KCl(s) + 3O(g) b. 2KClO 3 (s) 2KCl(s) + 3O 2 (g) c. KClO 3 (s) KCl(s) + O 3 (g) d. 2KClO 3 (s) K 2 Cl 2 (s) + 3O 2 (g)

2 7. For the reaction 2H 2 + O 2 2H 2 O which of the following can be answered only using the coefficients of the balanced equation? a. What weight of water is produced when 2.5 grams of hydrogen react completely? b. What weight of water is produced when 2.5 moles of hydrogen react completely? c. How many moles of water are produced from 4.0 grams of hydrogen and 32.0 grams of oxygen? d. How many moles of water are produced when 2.5 moles of hydrogen react completely? 8. The balanced equation for the complete combustion of propane is C 3 H 8 (g) + 5O 2 (g) 4H 2 O(g) + 3CO 2 (g) If 1 mole of propane and 10 moles of oxygen are placed in container, what will be left in the container after the reaction is complete? a. no propane, 5 moles of oxygen, 4 moles of water vapor, 3 moles of CO 2 b. no propane, no oxygen, 4 moles of water vapor, 3 moles of CO 2 c. no propane, no oxygen, 8 moles of water vapor, 6 moles of CO 2 d. none of the above combinations is correct 9. When ammonia gas comes in contact with hydrogen chloride gas the reaction is NH 3 (g) + HCl(g) NH 4 Cl(s) What weight of ammonium chloride, NH 4 Cl(s), is produced by the reaction of 34.0 grams of NH 3 (g) with 75.0 grams of HCl(g)? a g b g c. 107 g d. 109 g 10. Aspirin can be made by the following reaction: C 7 H 6 O 3 (s) + 2C 4 H 6 O 3 (l) C 9 H 8 O 4 (s) + C 2 H 4 O 2 (l) Salicylic acetic aspirin acetic acid anhydride acid If this reaction is carried out with a 95.0% yield, how much salicylic acid is needed to produce 90.0 grams of aspirin? a g b g c g d. 138 g 11. Which of the following is the balanced molecular equation for the reaction of silver nitrate, AgNO 3, with barium chloride, BaCl 2? a. AgNO 3 (aq) + BaCl 2 (aq) AgCl(s) + BaNO 3 (aq) b. 2AgNO 3 (aq) + BaCl 2 (aq) 2AgCl(s) + BaNO 3 (aq) c. AgNO 3 (aq) + BaCl 2 (aq) AgCl 2 (s) + BaNO 3 (aq) d. 2AgNO 3 (aq) + BaCl 2 (aq) 2AgCl(s) + Ba(NO 3 ) 2 (aq)

3 12. Oxidation can be defined as which of the following? a. loss of oxygen b. loss of electrons c. gain of hydrogen d. all of these correctly define oxidation 13. In a redox reaction which of the following is true for the oxidizing agent? a. it accepts electrons b. it is reduced c. both (a) and (b) are true d. both (a) and (b) are false 14. Which of the following is true about the combustion of a hydrocarbon? a. combustion is not a redox reaction b. oxygen is the oxidizing agent c. the hydrocarbon is the oxidizing agent d. all of these are true 15. Which of the following is true of a reaction in which heat is consumed? a. the reaction is endothermic b. the reaction is exothermic c. depending on the reaction the reaction may be either endothermic or exothermic d. there are more reactants than products 16. Which of the following is a unit used for air pressure? a. atmospheres b. millimeters of Hg c. torr d. all of these 17. Which of the following exerts the greatest pressure? a. a 20 gram object on a surface of 0.50 cm 2 b. a 40 gram object on a surface of 2.0 cm 2 c. a 60 gram object on a surface of 3.0 cm 2 d. an 80 gram object on a surface of 3.5 cm At constant temperature the pressure on a 6.0 liter sample of gas is increased from 1.0 atm to 2.0 atm. What is the new volume of the gas sample? a liters b liters c. 1.5 liters d. 3.0 liters

4 19. Suppose a balloon is filled so that its volume is 2.00 L when the pressure is 1.10 atm and the temperature is 300 K. What volume will it occupy if it rises to an elevation where the pressure is 418 torr and the temperature is 200 K? a liters b liters c liters d liters 20. If a 7.00 gram sample of molecular nitrogen at 10 o C occupies 2.50 L, what is the pressure of the sample? a atm b atm c atm d atm 21. A closed flask contains a 0.25 moles of O 2 which exerts a pressure of 0.50 atm. If 0.75 moles of CO 2 is added to the container what is the pressure of oxygen? a atm b. 1.0 atm c. 1.5 atm d. 2.0 atm 22. Which of the following is not an example of an intermolecular attraction? a. covalent bonding b. dipole-dipole interactions c. London dispersion forces d. hydrogen bonding 23. Which of the following molecules can have only London dispersion forces? a. CH 4 b. CO 2 c. both (a) and (b) d. neither (a) nor (b) 24. Which of the following molecules cannot engage in hydrogen bonding? a. CH 4 b. NH 3 c. H 2 O d. all of them 25. When comparing a liquid with a gas at the same temperature which of the following is true? a. the molecules in the liquid are much closer together than those in the gas b. the molecules in the liquid have greater kinetic energy than those in the gas c. both (a) and (b) are true d. both (a) and (b) are false

5 26. Which of the following affects the vapor pressure of a liquid? a. the mass of the sample b. the shape the sample c. the temperature of the sample d. the volume of the sample 27. Chloroform has a normal boiling point of 61.7 o C. Which of the following is true? a. at any temperature the vapor pressure of chloroform is greater than that of water b. chloroform is less volatile than water c. both (a) and (b) are true d. both (a) and (b) are false 28. Which regions of a heating curve correspond to regions where only a single phase of a material is present? a. horizontal regions b. regions with negative slope c. regions with positive slope d. it depends on the material 29. Which of the following phase changes does not involve a solid? a. evaporation b. melting c. sublimation d. none, they all involve a solid Phase diagram of water. The temperature and pressure scales are greatly reduced (and are non-linear). 30. Refer to the Figure above. Consider a sample of water initially at a temperature of 0 o C and a pressure of 660 torr. If the pressure is increased to 800 torr while the temperature is held constant, what phase transition will occur? a. solid to liquid b. solid to vapor c. liquid to vapor d. no phase change will occur

6 31. In the space provided, draw the Lewis dot structure of (remember to include lone pair electrons, if present, into your drawing): a. CH 3 NH 2 (3 points) b. GeF 4 (3 points) 32. In photosynthesis, green plants convert CO 2 and H 2 O to glucose, C 6 H 12 O 6. How many grams of CO 2 are required to produce 5.1 g of glucose? (6 points) CO 2 (g) + H 2 O C 6 H 12 O 6 (aq) + O 2 (g) (Note: unbalanced) 33. What volume is occupied by 3.9 g of propane gas, C 3 H 8, at 28 C and 2.13 atm pressure? (R = L atm/mol K, 3 points) 34. What will be the final temperature (in C) when we add 1500 cal of heat to 8 g of ice at 0 C? (Ice: Heat of Fusion = 80 cal/g; Water: Specific Heat = 1.00 cal/g C) (5 points)

CHEM 150 Exam 2. Name Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.

CHEM 150 Exam 2. Name Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. CHEM 150 Exam 2 Name Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. _A D 1. Formic acid, HCOOH, is what causes the sting of bee stings. What