MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Transcription

1 General Chemistry PHS 1015 Practice Exam 4 Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which of the following statements about pressure is FALSE? 1) A) Pressure is caused by gas molecules colliding with surfaces. B) The atmosphere has a pressure as the components of air collide with surfaces. C) After creating a pressure difference, the atmospheric pressure can push liquid up a straw. D) A deep well dug in the ground must have the pump located at the bottom of well in order to have the water come to the surface. E) All of the above statements are true. 2) Which of the following is NOT part of the Kinetic Molecular Theory? 2) A) Gas particles do not repel each other. B) There is a large distance between gas particles as compared to their relative size. C) The size of the actual gas particles is small compared to the volume of the whole gas. D) The average energy of the particles is dependent on the molecular mass of the particle. E) All of the above statements are part of the Kinetic Molecular Theory. 3) Which of following statements are consistent with the Kinetic Molecular Theory? 3) A) Gases are compressible because the volume taken up by the gas is almost entirely open space. B) Gases assume the shape and volume of their container because they are in constant, straight-line motion. C) Gases have a low density because there is so much empty space between the particles. D) Gas particles collide with each other and surfaces without losing any energy. E) All of the above statements are consistent with the Kinetic Molecular Theory. 4) All of the following statements are consistent with the kinetic molecular theory of gases EXCEPT: 4) A) The size of the gas molecules is negligible compared to the total volume of the gas. B) The average kinetic energy of the molecules of a gas is proportional to the temperature of the gas in kelvins. C) The gas molecules collide with each other and with the surfaces around them. D) Strong attractive forces hold the gas molecules together. 5) 1 atm is equal to: 5) A) 760 mm Hg. B) 760 torr. C) 101,325 Pa. D) 14.7 psi. E) all of the above 6) 1 torr is equal to: 6) A) 760 mm Hg. B) 1 mm Hg. C) 1 Pa. D) 14.7 psi. E) all of the above 1

2 7) A barometer uses mercury because: 7) A) it is a convenient, safe, lightweight material. B) the density of mercury is very large which allows the barometer to be short. C) it is the traditional substance used, water could be as easily used. D) it is the only liquid metal at room temperature. E) All of the above are true. 8) What is the equivalent pressure of atm in units of mm Hg? 8) A) 688 B) 840 C) D) ) What is the equivalent pressure of 1520 torr in units of atm? 9) A) 203,000 B) 380. C) 2.00 D) ) What is the equivalent pressure of 760 torr in units of mm Hg? 10) A) 760 B) 1 C) 14.7 D) ) What is the equivalent pressure of 968 mm Hg in units of atm? 11) A) 1.27 atm B) atm C) 968 atm D) 1.30 atm 12) Boyle's Law is expressed as: 12) A) V is proportional to 1 P B) P is proportional to V C) V is proportional to 1 T D) V is proportional to T 2

3 13) To solve problems using Boyle's Law, which mathematical equation should be used? 13) A) P 1 V1 = P 2 V2 B) P1V1 = P2V2 C) V 1 P1 = V 2 P2 D) P2V1 = P1V2 14) One liter of a gas is in a sealed chamber containing a moveable piston. If the piston is moved so that the volume of the gas is compressed to a volume of one-half liter, what will happen to the pressure on the gas? (Assume the temperature is constant and no gas particles are lost.) A) The pressure will remain the same. B) The pressure will be half of the original value. C) The pressure will be twice the original value. D) It would be impossible to move the piston since gases are not compressible. 15) A balloon filled with L of air at sea level is submerged in the water to a depth that produces a pressure of 3.25 atm. What is the volume of the balloon at this depth? A) 1.63 L B) L C) 6.50 L D) L 16) Divers often inflate heavy duty balloons attached to salvage items on the sea floor. If a balloon is filled to a volume of 3.00 L at a pressure of 2.50 atm, what is the volume of the balloon when it reaches the surface? A) 7.50 L B) 1.20 L C) L D) 5.50 L 17) The initial volume of a gas cylinder is ml. If the pressure of a gas inside the cylinder changes from mm Hg to mm Hg, what is the final volume the gas occupies? A) L B) ml C) L D) ml 14) 15) 16) 17) 3

4 18) Charles's Law is expressed as: 18) A) V is proportional to 1 P B) P is proportional to V C) V is proportional to 1 T D) V is proportional to T 19) To solve problems using Charles's Law, which mathematical equation should be used? 19) A) V 1 T1 = V 2 T2 B) T1V1 = T2V2 C) P 1 V2 = P 2 V1 D) P2V1 = P1V2 20) Which one of the following is impossible for an ideal gas? 20) A) 1 V2 = T 1 T2 ( 1 V1 ) B) V 1 T1 = V 2 T2 C) V2 = ( T 2 T1 ) V 1 D) V1T1 = V2T2 21) When must temperature values in gas law calculations be expressed in kelvin units? 21) A) only for Charles's law B) only for the Ideal Gas law C) only for the Combined Gas law D) never E) always 22) A 5.00 liter balloon of gas at 25 C is cooled to 0 C. What is the new volume (liters) of the balloon? 22) A) 0 liters B) 22.4 liters C) 5.46 liters D) 4.58 liters 4

5 23) A gas sample occupies 3.50 liters of volume at 20. C. What volume will this gas occupy at 100 C (reported to three significant figures)? A) L B) 2.75 L C) 4.46 L D) 17.5 L 24) What is the final volume of a balloon that was initially ml at 25 C and was then heated to 50 C? A) 461 ml B) 193 ml C) 1.00 L D) 542 ml 25) If the volume of a gas container at 32.0 C changes from 1.55 L to 755 ml, what will the final temperature be? A) 149 C B) 353 C C) 273 C D) -124 C 26) What is the initial temperature of a gas if the volume changed from 1.00 L to 1.10 L and the final temperature was determined to be C? A) 480 C B) -41 C C) 232 C D) 207 C 27) A balloon originally had a volume of L at 44 C and a pressure of 729 torr. To what temperature must the balloon be cooled to reduce its volume to 378 ml if the pressure remained constant? A) 0 C B) 38 C C) 95 C D) 273 C 28) Gas density can be calculated by dividing the mass of gas by its volume. If you took a balloon of gas and then warmed the balloon in a sunny window, what can now be said about the density of the gas in the balloon? A) The gas density will remain the same. B) The gas density will increase. C) The gas density will decrease. D) The density of gases is independent of temperature. 23) 24) 25) 26) 27) 28) 5

6 29) Which of the following statements is TRUE for gases? 1. The temperature of a gas is inversely proportional to its pressure. 2. The volume of a gas is directly proportional to the pressure in torr. 3. The pressure of a gas is due to collisions of the gas molecules. A) 1 only B) 2 only C) 3 only D) 1 and 2 only E) 1 and 3 only 29) 30) What is the proper form of the combined gas law? 30) A) P 1T1 V1 = P 2T2 V2 B) V 1T1 P1 C) P 1V1 T1 = V 2T2 P2 = P 2V2 T2 D) P1V1T1 = P2V2T2 31) A certain volume of gas was confined in a rigid container. If the pressure of the gas sample in the container was doubled, what happened to the temperature? A) The Kelvin temperature decreased by one-half. B) The Kelvin temperature doubled. C) The Kelvin temperature increased four times. D) The Kelvin temperature decreased one-third. E) not enough information 32) Suppose a balloon was released from the ground and rose to such a height that both the atmospheric pressure and atmospheric temperature decreased. Which statement is TRUE? A) Both the temperature and pressure changes act to increase the balloon's volume. B) Both the temperature and pressure changes act to decrease the balloon's volume. C) The temperature change acts to increase the balloon's volume. D) The pressure change acts to decrease the balloon's volume. 33) If the initial pressure of a system was 1.00 atm and the volume was halved and the kelvin temperature was tripled, what is the final pressure? A) 2.00 atm B) atm C) 1.50 atm D) 6.00 atm E) not enough information 31) 32) 33) 6

7 34) A 325 ml sample of gas is initially at a pressure of 721 torr and a temperature of 32 C. If this gas is compressed to a volume of 286 ml and the pressure increases to 901 torr, what will be the new temperature of the gas (reported to three significant figures in C)? A) 35.2 C B) 335 C C) 62.4 C D) 215 C 35) A sample of helium gas initially at 37.0 C, 785 torr and 2.00 L was heated to 58.0 C while the volume expanded to 3.24 L. What is the final pressure in atm? A) 517 B) C) 1.79 D) ) What is the final volume of a ml gas container that increased in temperature from 299 K to 333 K while the pressure increased from 1.00 atm to 1.54 atm? A) L B) 2.77 L C) L D) 1.45 L 37) What is the initial temperature ( C) of a system that has the pressure decreased by 10 times while the volume increased by 5 times with a final temperature of 150 K? A) 27 B) 75 C) -198 D) ) 35) 36) 37) 38) Avogadro's Law is expressed as: 38) A) V is proportional to 1 n B) P is proportional to n C) n is proportional to 1 T D) V is proportional to n 7

8 39) To solve problems using Avogadro's Law, which mathematical equation should be used? 39) A) n 1 P1 = n 2 P2 B) n1v1 = n2v2 C) V 1 n1 = V 2 n2 D) P1V1 = P2V2 40) What happens to the volume of a gas when you double the number of moles of gas while keeping the temperature and pressure constant? A) The volume is halved. B) The volume doubles. C) The volume decreases, but more information is needed. D) The volume increases, but more information is needed. 41) How many moles of gas were added to a balloon that started with 2.3 moles of gas and a volume of 1.4 L given that the final volume was 7.2 L? A) 9.5 B) 4.4 C) 12 D) ) If each of the following gas samples have the same temperature and pressure, which sample has the greatest volume? A) 1 gram of O2 B) 1 gram of Ar C) 1 gram of H2 D) all have the same volume E) not enough information 40) 41) 42) 43) Which of the following gas law relationships is true? 43) A) V 1/P B) V T C) V n D) all of the above are true are true 44) For an ideal gas, which of the following pairs of variables are inversely proportional to each other (if all other factors remain constant)? A) P, V B) P, T C) V, T D) n, P 44) 8

9 45) The ideal gas law is: 45) A) PV = nrt B) P = nrt V C) T = PV nr D) V = nrt P E) All of the above are forms of the ideal gas law. 46) A sample of mole of gas has a volume of 748 ml at 28 C. Calculate the pressure of this gas. (R= L atm / mol K) A) 8.42 atm B) atm C) atm D) atm 47) What is the pressure of a 3.00 L gas vessel that has 18.0 grams of helium at 25 C? (R= L atm/ mol K) A) 147 atm B) 36.7 atm C) 32.6 atm D) 1.81 atm 48) What is the temperature ( C) of 2.48 moles of gas stored in a 30.0 L container at 1559 mm Hg? (R= L atm/ mol K) A) 302 B) 189 C) 29 D) ) Which conditions can cause nonideal gas behavior by 1) decreasing the space between gas particles or 2) by slowing gas particles so that interactions are significant? A) 1) high pressure; 2) high temperature B) 1) high pressure; 2) low temperature C) 1) low pressure; 2) high temperature D) 1) low pressure; 2) low temperature 50) A 3.76 g sample of a noble gas is stored in a 2.00 L vessel at 874 torr and 25 C. What is the noble gas? (R= L atm/ mol K) A) He B) Ne C) Ar D) Kr E) not enough information 46) 47) 48) 49) 50) 9

10 51) Which of the following diatomic elements would have a mass of grams stored in a 3.82 L container at 3,632 mm Hg and 100 C? (R= L atm/ mol K) A) H2 B) Br2 C) F2 D) O2 E) not enough information. 51) 52) What is the major component of the air we breathe? 52) A) nitrogen B) oxygen C) argon D) carbon dioxide E) smog 53) What is the third most abundant component of dry air? 53) A) carbon dioxide B) oxygen C) nitrogen D) argon E) smog 54) If a mixture of gases contained 78% nitrogen at a pressure of 984 torr and 22% carbon dioxide at 345 torr, what is the total pressure of the system? A) 1,329 atm B) 17.5 cm Hg C) 639 torr D) 1.75 atm 55) A gas cylinder contains only the gases radon, nitrogen, and helium. The radon has a pressure of 222 torr while the nitrogen has a pressure of 446 torr. If the total pressure inside the cylinder is 771 torr, what is the pressure that is due to the helium? A) 771 torr B) 668 torr C) 549 torr D) 103 torr 56) A "shielding gas" mixture of argon and carbon dioxide is sometimes used in welding to improve the strength of the weld. If a gas cylinder of this two-part mixture was at 4.0 atm pressure and this mixture was 90.% argon, what would be the pressure due to the carbon dioxide gas component? A) 3.6 atm B) 0.40 atm C) 10. atm D) 4.0 atm 54) 55) 56) 10

11 57) What problem could happen if deep sea divers used pure oxygen in their tanks? 57) A) hypoxia B) oxygen toxicity C) nitrogen narcosis D) rapture of oxygen 58) Human lungs have evolved to breathe oxygen at a pressure as that in the atmosphere, 0.21 atm. If a particular heliox mixture to be carried by a scuba diver is at a pressure of 7.00 atm, what should be the partial pressure due to helium in order to maintain the pressure due to oxygen at 0.21 atm? A) 0.21 atm B) 7.00 atm C) 6.79 atm D) 7.21 atm 59) The vapor pressure of water at 20.0 C is 17.5 mm Hg. If the pressure of a gas collected over water was measured to be mm Hg. What is the pressure of the pure gas? A) atm B) atm C) atm D) atm 60) Hydrogen gas produced in the laboratory by the reaction of zinc and hydrochloric acid was collected over water at 25 C. The barometric pressure at the time was mm Hg. What is the pressure of dry hydrogen gas if the vapor pressure of water at 25 C is 23.8 mm Hg? A) mm Hg B) mm Hg C) mm Hg D) mm Hg 61) Suppose a chemical reaction generated a 50% nitrogen/50% oxygen (by volume) mixture of gas that had a total volume of 22.4 liters at STP. This gas sample is composed of: A) 1 mole of nitrogen and 1 mole of oxygen. B) 0.5 mole of nitrogen and 0.5 mole of oxygen. C) 50 mole of nitrogen and 50 mole of oxygen. D) 28 mole of nitrogen and 32 mole of oxygen. 58) 59) 60) 61) 62) Which set of conditions reflect STP? 62) A) 298 K, 1 atm B) 25 C, 14.7 psi C) 373 K, 760 torr D) 273 K, 1 Pa E) 273 K, 760 mm Hg 11

12 63) At STP, g of a noble gas occupies L. What is the identity of the noble gas? (R= L atm/ mol K) A) He B) Ne C) Ar D) Kr E) not enough information 64) Suppose you had a balloon containing 1 mole of helium at STP and a balloon containing 1 mole of oxygen at STP. Which statement is TRUE? A) The balloons will have the same volume. B) The balloons will have the same mass. C) Both A) and B) are true. D) Neither A) nor B) are true. E) not enough information 65) Ammonia gas decomposes according to the equation: 2NH3(g) N2(g) + 3H2(g) If 15.0 L of nitrogen is formed at STP, how many liters of hydrogen will be produced (also measured at STP)? A) 15.0 L B) 30.0 L C) 45.0 L D) 90.0 L E) not enough information 66) Water can be formed according to the equation: 2H2 (g) + O2 (g) 2H2O (g) If 8.0 L of hydrogen is reacted at STP, exactly how many liters of oxygen at STP would be needed to allow complete reaction? A) 4.0 L B) 2.0 L C) 1.0 L D) 8.0 L 67) How many liters of O2 (g) are needed to react completely with 56.0 L of CH4 (g) at STP to produce CO2 (g) and H2O (g)? Given: CH4 (g) + 2O2 (g) CO2 (g) + H2O (g) A) 28.0 L B) 56.0 L C) 84.0 L D) 112. L 63) 64) 65) 66) 67) 12

13 68) What is the pressure of 760 mm Hg when expressed in units of in Hg? 68) A) in Hg B) 101,325 in Hg C) 760 in Hg D) 1 in Hg 69) What is the final pressure of a system (atm) that has the volume increased from 0.75 L to 1.1 L with an initial pressure of 1.25 atm? A) 1.1 B) 0.85 C) 1.8 D) ) 70) What is the final volume (L) of a 10.0 L system that has the pressure quartered? 70) A) B) 17.1 C) 2.50 D) ) What is the final volume of a gas that initially occupies 2.50 L at 298 K and is subsequently heated to 321 K? A) 2.69 L B) 2.96 L C) 2.23 L D) 2.32 L 72) What is the change in temperature of a 2.50 L system when its volume is reduced to 1.75 L if the initial temperature was 298 K? A) 209 K B) 290 K C) -89 K D) -98 K 73) What is the final volume (L) of a 1.00 L system at 315 K and 1.10 atm if STP conditions are established? A) 1.05 B) C) 1.50 D) ) 72) 73) 13

14 74) What is the final pressure (expressed in atm) of a 3.05 L system initially at 724 mm Hg and 298 K, that is compressed to a final volume of 2.51 L at 273 K? A) 1.06 B) 1.60 C) 806 D) ) A rigid cylinder contains 2.00 liters of gas at a temperature of 25 C. If the pressure of this gas is changed from atmospheres to 1.50 atmospheres, what will be the new temperature (in Kelvin, reported to three significant figures) of the gas? (The volume is constant.) A) 99.3 K B) 75.0 K C) 8.33 K D) 894 K 76) If the number of moles of a gas initially contained in a 2.10 L vessel is doubled, what is the final volume of the gas in liters? (Assume the pressure and temperature remain constant.) A) 6.30 B) 1.05 C) 4.20 D) ) What is the volume (in liters) of 1.00 mole of krypton gas that has a pressure of 1140 mm Hg and a temperature of 25.0 C? (R= L atm/ mol K) A) 1.37 B) 16.3 C) D) ) What is the molecular weight of a gas if a 21.0 g sample has a pressure of 836 mm Hg at 25.0 C in a 2.00 L flask? (R= L atm/ mol K) A) 243 amu B) 1.89 amu C) 234 amu D) 11.1 amu 74) 75) 76) 77) 78) 79) What is the pressure of a 1.0 L flask containing 0.60 g of He at 25 C? (R= L atm/ mol K) 79) A) 98 atm B) 3.7 atm C) 7.3 atm D) 15 atm 14

15 80) What is the volume of 28.0 g of nitrogen gas at STP? 80) A) 33.6 L B) 11.2 L C) 22.4 L D) 44.8 L 81) Intermolecular forces are responsible for: 81) A) the taste sensations. B) the shape of protein molecules. C) the function of DNA. D) the existence of liquids and solids. E) all of the above 82) Which state of matter has a high density and an indefinite shape? 82) A) solids B) liquids C) gases D) both solids and liquids 83) Which state of matter has a high density and a definite volume? 83) A) solids B) liquids C) gases D) both solids and liquids 84) Which state of matter has a low density and an indefinite volume? 84) A) solids B) liquids C) gases D) both solids and liquids 85) Which state of matter has a low density and is easily compressed? 85) A) solids B) liquids C) gases D) both solids and liquids 86) Which statement about surface tension is FALSE? 86) A) Liquids tend to minimize their surface area. B) Molecules on the surface of the liquid have fewer molecules to interact with. C) Increased intermolecular forces increase surface tension. D) Items with densities lower than water will sink due to surface tension. E) All of the above statements are true. 15

16 87) The tendency of a liquid to minimize its surface area is called: 87) A) capillary action. B) viscosity. C) surface tension. D) vaporization. 88) The measure of the resistance to the flow of a liquid is called: 88) A) vapor pressure. B) sublimation. C) viscosity. D) condensation. 89) The change of a substance from a liquid to a gaseous form is called: 89) A) dynamic equilibrium. B) heat of fusion. C) condensation. D) vaporization. E) volatile. 90) A situation where two opposite processes are occurring at equal rates, and no net change is taking place, is called: A) vaporization. B) condensation. C) evaporation. D) dynamic equilibrium. 90) 91) Increasing the intermolecular forces of a liquid will do which of the following? 91) A) increase the viscosity B) decrease the evaporation rate C) increase the surface tension D) decrease the vapor pressure E) all of the above 92) You can increase the vapor pressure of a liquid by: 92) A) increasing temperature. B) increasing the viscosity. C) establishing dynamic equilibrium. D) using a nonvolatile compound. E) all of the above 93) Which statement about boiling point is FALSE? 93) A) The boiling point is higher for compounds with strong intermolecular forces. B) The boiling point is higher for compounds with a high viscosity. C) The boiling point of a compound is an absolute constant. D) The boiling point of a compound is higher for nonvolatile compounds. E) All of the above statements are true. 16

17 94) Evaporation is: 94) A) increased by increasing temperature. B) an endothermic process. C) the opposite process to condensation. D) a cooling process for humans when they sweat. E) all of the above 95) Which of the following statements is FALSE? 95) A) Evaporation is an endothermic process. B) A puddle of water cools down as it evaporates. C) As a liquid is converted into a gas, the liquid absorbs heat. D) All of the above are true. E) None of the above are true. 96) The opposite process of freezing is: 96) A) evaporation. B) sublimation. C) boiling. D) condensation. 97) The rate of vaporization of a liquid can be increased by: 1. increasing the surface area 2. increasing the temperature 3. increasing the strength of the intermolecular forces A) 1 only B) 2 only C) 3 only D) 1 and 2 only E) 2 and 3 only 97) 98) Liquids that have high vapor pressure and low boiling points are called: 98) A) abnormal liquids. B) volatile liquids. C) non-volatile liquids. D) viscous liquids. 99) The amount of heat required to melt one mole of a solid is called the: 99) A) heat of vaporization. B) heat of fusion. C) heating curve. D) cooling curve. 17

18 100) Compare a small pot of water that is boiling vigorously to a large pot of water that is boiling gently. Which statement is TRUE? A) The small pot is boiling at higher temperature than the large pot. B) The large pot is boiling at a higher temperature than the small pot. C) Both pots are boiling at the same temperature. D) The vapor pressure of the liquid is greater than the pressure above the pot in each case. 101) When sufficient quantity of heat has been added to reach the boiling point of a solution, what happens to any additional heat added? A) Additional heat is used to evaporate the liquid as the process is endothermic and requires continued input of energy. B) Additional heat raises the temperature of the liquid which in turn increases the rate at which boiling occurs. C) Additional heat lowers the intermolecular forces of the liquid which in turn increases the volatility of the liquid. D) Additional heat alters the viscosity and the surface tension of the liquid which raises the vapor pressure and increases the boiling point which is why you must continually heat the solution. E) None of the above are correct statements. 102) What is the heat of vaporization(kj/mol) if it takes 3,452 J of heat to completely vaporize 2.68 moles of the liquid at its boiling point? A) 1288 B) 1.29 C) D) ) How many joules of heat are needed to completely vaporize grams of water at its boiling point? Given Hvap = 40.6 kj/mol A) B) C) D) ) How many kilojoules of heat are needed to completely vaporize 42.8 grams of C4H10O at its boiling point? Given Hvap = 26.5kJ/mol A) B) 9.49 C) 15.3 D) ) 101) 102) 103) 104) 18

19 105) What happens as you start to add heat to a solid substance? 105) A) Thermal energy causes the components of the solid to vibrate faster. B) When the melting point is reached, the thermal energy is sufficient to overcome intermolecular forces holding the components at their stationary points. C) Increasing the rate of heating of a substance at its melting point only causes more rapid melting. D) If a liquid forms, continued heating results in increasing the liquid temperature. E) all of the above 106) If we supply additional heat to a solid in equilibrium with its liquid at the melting point, the thermal energy added is used to: A) overcome the intermolecular forces that hold the solid together. B) expand the solid. C) change the liquid back to solid. D) change solid to liquid. E) raise the temperature of the solid above its melting point. 106) 107) When you make ice cubes: 107) A) it is an endothermic process. B) it is an exothermic process. C) the heat of vaporization must be removed. D) the process is referred to scientifically as sublimation. 108) Which statement is TRUE in describing what occurs when a solid melts to a liquid? 108) A) The process is endothermic and the heat of fusion is positive. B) The process is endothermic and the heat of fusion is negative. C) The process is exothermic and the heat of fusion is positive. D) The process is exothermic and the heat of fusion is negative. E) not enough information 109) Gaseous water vapor can frost the windows of a car on a cold morning. This process of a gas changing directly into a solid is known as: A) deposition. B) melting. C) condensation. D) sublimation. 110) Paradichlorobenzene, a material used in "moth balls," is known to go directly from a solid form to a gaseous form. This process is known as: A) melting B) evaporation C) condensation D) boiling E) sublimation 109) 110) 19

20 111) How much energy does it take to melt a g ice cube? Hfus= 6.02 kj/mol A) 102 kj B) 108 kj C) 936 J D) 5.64 kj 111) 112) How many grams of C4H10O can be melted by J? Given Hfus=7.27 kj/mol A) 14.5 B) 3.64 C) 20.4 D) ) In northern climates, it is common to have a layer of frost form on cars that have been out overnight in the winter. During the day the frost layer disappears despite the temperature of the ice remaining below freezing. How? A) The frost melts due to the sun heating the surface of the car above the melting point. B) The frost evaporates due to the sun heating the solid. C) The frost cycles as does the saturation level of moisture in the winter air does from night to day. D) The frost sublimes directly from solid ice to water vapor. 112) 113) 114) Which intermolecular force is present in all molecules and atoms? 114) A) dispersion forces B) dipole-dipole forces C) hydrogen bonding D) X-forces 115) Which intermolecular force is due to the formation of an instantaneous dipole? 115) A) dispersion forces B) dipole-dipole forces C) hydrogen bonding D) X-forces 116) The ability of sodium chloride to mix with water is most likely due to: 116) A) dispersion force B) ion-dipole force C) dipole-dipole force D) hydrogen bonding 20

21 117) Which substance below has dipole-dipole forces? 117) A) CH4 B) CO2 C) F2 D) H2S 118) Which intermolecular force increases with increasing molar mass? 118) A) dispersion forces B) dipole-dipole forces C) hydrogen bonding D) X-forces 119) Which noble gas has the highest boiling point? 119) A) He B) Ne C) Ar D) Kr E) Xe 120) Assuming that the molecules carbon monoxide (CO) and nitrogen (N2) have similar electron clouds, which statement below is TRUE? A) CO has the higher boiling point because it experiences dipole-dipole forces. B) N2 has the higher boiling point because it experiences dipole-dipole forces. C) The N2 has the higher boiling point because it has greater dispersion forces. D) Both CO and N2 must have the same boiling point. 120) 121) Which intermolecular force is common to all polar molecules but NOT nonpolar molecules? 121) A) dispersion forces B) dipole-dipole forces C) hydrogen bonding D) X-forces 122) Substance A is a molecular compound that dissolves in gasoline but not in water. The molecules of A are very likely: A) metallic. B) nonmetallic. C) polar. D) nonpolar. 122) 123) Which substance is most likely to be miscible with water? 123) A) CF4 B) Br2 C) CS2 D) CHCl3 21

22 124) Which statement below is FALSE? 124) A) A hydrogen bond is the strongest of the intermolecular forces. B) A hydrogen atom must be bonded directly to fluorine, oxygen, or nitrogen to exhibit hydrogen bonding. C) The large electronegativity difference between hydrogen and an F, O, or N atom is essential for the formation of a hydrogen bond. D) A hydrogen bond is only 2-5% the strength of a typical covalent bond. 125) Which molecule below has hydrogen bonding? 125) A) CH4 B) HCl C) H2 D) CH3CH2OH E) all of the above 126) Which molecule below has hydrogen bonding? 126) A) NH3 B) CH3OH C) H2O D) HF E) all of the above 127) Which compound in liquid form will have the highest vapor pressure? 127) A) CH4 B) CH3CH3 C) CH3C(O)CH3 D) CH3CH2OH E) not enough information 128) Which intermolecular force is the strongest? 128) A) dispersion force B) dipole-dipole force C) hydrogen bonding D) ion-dipole force 129) Which intermolecular forces are found in CCl4? 129) A) dispersion forces B) dipole-dipole forces C) hydrogen bonding D) X-forces 22

23 130) Which intermolecular forces are found in CO2? 130) A) dispersion forces B) dipole-dipole forces C) hydrogen bonding D) dispersion forces and dipole-dipole forces 131) What types of forces exist between I2 molecules? 131) A) dispersion forces B) dipole-dipole forces C) hydrogen bonding D) ion-dipole forces 132) Which intermolecular force found in CCl2H2 is the strongest? 132) A) dispersion forces B) dipole-dipole forces C) hydrogen bonding D) X-forces 133) Consider the three compounds below, then choose the compound(s) that have hydrogen bonding. 1) H2 2) CH4 3) HF A) Only compound 1 has hydrogen bonding. B) Only compound 2 has hydrogen bonding. C) Only compound 3 has hydrogen bonding. D) All three of these compounds have hydrogen bonding. E) None of these compounds have hydrogen bonding. 133) 134) Which compound will have the highest boiling point? 134) A) CH4 B) CH3CH3 C) CH3C(O)CH3 D) CH3CH2OH E) not enough information 135) Which substance would be expected to have the highest boiling point? 135) A) N2 B) O2 C) CO2 D) CO E) not enough information 23

24 136) Rank the compounds NH3, CH4, and PH3 in order of increasing boiling point. 136) A) NH3 < CH4< PH3 B) CH4< NH3 < PH3 C) NH3 < PH3< CH4 D) CH4 < PH3 < NH3 E) PH3< NH3 < CH4 137) Dry ice (solid CO2) is which type of solid? 137) A) molecular solid B) ionic solid C) covalent atomic solid D) nonbonding atomic solid E) metallic atomic solid 138) Which substance below is an ionic solid? 138) A) Cu (s) B) H2O (s) C) MgO (s) D) C6H12O6 (s) 139) NaCl is which type of solid? 139) A) molecular solid B) ionic solid C) covalent atomic solid D) nonbonding atomic solid E) metallic atomic solid 140) Silicon is which type of solid? 140) A) molecular solid B) ionic solid C) covalent atomic solid D) nonbonding atomic solid E) metallic atomic solid 141) Copper is which type of solid? 141) A) molecular solid B) ionic solid C) covalent atomic solid D) nonbonding atomic solid E) metallic atomic solid 142) Which atomic solid has the highest melting point? 142) A) Cu B) Si C) Xe D) Fe E) not enough information 24

25 143) What are the principal forces holding ice together? 143) A) dispersion forces only B) electrostatic attraction C) intermolecular forces D) sea of electrons 144) Why is water considered an unusual molecule? 144) A) No molecule of similar size is a liquid at room temperature. B) No molecule of similar size has as high a boiling point. C) Water can dissolve many polar and ionic compounds. D) Water expands upon freezing. E) all of the above 145) The reason for many of the unique properties of water is: 145) A) dispersion forces. B) the ability to form hydrogen bonds. C) high surface tension and low volatility. D) moderate viscosity and expanding upon freezing. E) all of the above 146) Which sequence correctly shows the increasing density of the three phases of water? 146) A) solid < liquid < gas B) gas < liquid < solid C) gas < solid < liquid D) liquid < gas < solid 147) How many kj of heat are needed to completely vaporize 3.30 moles of H2O? The heat of vaporization for water at the boiling point is 40.6 kj/mole. A) 12.3 B) 134 C) 67.0 D) ) How many kj of heat are needed to completely vaporize 23.4 g of H2O? The heat of vaporization for water at the boiling point is 40.6 kj/mole. A) 31.2 B) 52.8 C) 23.4 D) ) A 250 gram sample of water at the boiling point had 45.0 kj of heat added. How many grams of water were vaporized? Heat of vaporization for water is 40.6 kj/mole. A) 1.11 B) 20.0 C) D) ) 148) 149) 25

26 150) How many kj of heat are needed to completely melt 1.70 moles of H2O, given that the water is at its melting point? The heat of fusion for water is 6.02 kj/mole. A) 30.6 B) 10.2 C) 3.54 D) ) How many kj of heat are needed to completely melt 17.3 g of H2O, given that the water is at its melting point? The heat of fusion for water is 6.02 kj/mole. A) B) 5.79 C) 1.04 D) ) How many kj of heat are needed to completely melt 95.3 g of copper metal, given that the metal is at its melting point? The heat of fusion for this metal is 13.1 kj/mole. A) 19.6 B) 43.0 C) 1250 D) ) 151) 152) 26

27 Answer Key Testname: GENERAL CHEMISTRY PHS 1015 PRACTICE EXAM 4 1) E 2) D 3) E 4) D 5) E 6) B 7) B 8) A 9) C 10) A 11) A 12) A 13) B 14) C 15) B 16) A 17) C 18) D 19) A 20) D 21) E 22) D 23) C 24) D 25) D 26) D 27) A 28) C 29) C 30) C 31) B 32) E 33) D 34) C 35) B 36) C 37) A 38) D 39) C 40) B 41) A 42) C 43) D 44) A 45) E 46) A 47) B 48) C 49) B 50) C 27

28 Answer Key Testname: GENERAL CHEMISTRY PHS 1015 PRACTICE EXAM 4 51) D 52) A 53) D 54) D 55) D 56) B 57) B 58) C 59) C 60) B 61) B 62) E 63) B 64) A 65) C 66) A 67) D 68) A 69) B 70) D 71) A 72) C 73) D 74) A 75) D 76) C 77) B 78) C 79) B 80) C 81) E 82) B 83) D 84) C 85) C 86) D 87) C 88) C 89) D 90) D 91) E 92) A 93) C 94) E 95) D 96) E 97) D 98) B 99) B 100) C 28

29 Answer Key Testname: GENERAL CHEMISTRY PHS 1015 PRACTICE EXAM 4 101) A 102) B 103) B 104) C 105) E 106) D 107) B 108) A 109) A 110) E 111) D 112) C 113) D 114) A 115) A 116) B 117) D 118) A 119) E 120) A 121) B 122) D 123) D 124) E 125) D 126) E 127) A 128) D 129) A 130) A 131) A 132) B 133) C 134) D 135) D 136) D 137) A 138) C 139) B 140) C 141) E 142) B 143) C 144) E 145) B 146) C 147) B 148) B 149) B 150) B 29

30 Answer Key Testname: GENERAL CHEMISTRY PHS 1015 PRACTICE EXAM 4 151) B 152) A 30