LABORATORY SCIECNCE CHEMISTRY EXAM 2023/2024 GRADED A+ UPDATED QUESTIONS AND ANSWERS, Exams of Laboratory Practices and Management

Download LABORATORY SCIECNCE CHEMISTRY EXAM 2023/2024 GRADED A+ UPDATED QUESTIONS AND ANSWERS and more Exams Laboratory Practices and Management in PDF only on Docsity! LABORATORY SCIECNCE CHEMISTRY EXAM 2023/2024 GRADED A+ UPDATED QUESTIONS AND ANSWERS Question 1 of 25 4.0 / 4.0 Points `I am holding a balloon containing 439 mL of gas over my fireplace. The temperature and pressure of the gas inside the balloon is 317.15 K and 0.959 atm, respectively. Suppose I don't want the pressure to change, but I want to the volume to go down to 0.378 L. What is the temperature that I need to reach when I cool down the balloon? To what temperature (in Celsius) must the balloon be cooled to reduce its volume to 0.378 L if the pressure doesn't change (remained constant)? • A. 273°C • B. 0°C • C. 38°C • D. 95°C Feedback: Great! Gas Laws discussed in Chapter 8. Question 2 of 25 4.0 / 4.0 Points What is the mass, in grams, of 6.82 L of nitrogen monoxide at STP? R = 0.0821 L atm / mol K • A. 0.010 g • B. 4.86 g • C. 0.304 g • D. 9.12 g Feedback: Great! Gas Laws discussed in Chapter 8. Question 3 of 25 4.0 / 4.0 Points `I have a cylinder sitting in my lab that contains 1.55 L of gas, and it's temperature is 305.15 K. If I compress the cylinder and change the volume to 0.755 L, what will be the new temperature in Celsius? • A. 149°C • B. -124°C • C. 353°C • D. 273°C Feedback: Great! Gas Laws discussed in Chapter 8. Question 4 of 25 4.0 / 4.0 Points A sample of gas has an initial volume of 3.5 L at a pressure of 970 torr and a temperature of 25*C. If the sample is heated to a temperature of 40*C and expands to a volume of 6.8 L, what is the final pressure in torr? • A. 5.2 x102 torr  C. 273 K, 1 Pa • D. 273 K, 760 mm Hg • E. 373 K, 760 torr Feedback: Great! Gas Laws discussed in Chapter 8. Question 8 of 25 4.0 / 4.0 Points `I have Pensieve in my office. You Harry Potter fans will know what I am talking about :). Right now, my Pensieve (think of it as a bowl) is just filled with water with a temperature of 20.0°C and with a vapor pressure of 17.5 torr. If I collect "magic gas" over this water, and the total gas pressure of the gas solution is found to be 453.0 torr, what would be the pressure of the pure magic gas in atm? • A. 0.573 atm • B. 0.619 atm • C. 0.0230 atm • D. 0.596 atm Feedback: Great! Gas Laws discussed in Chapter 8. Question 9 of 25 4.0 / 4.0 Points `I have a sealed cylinder sitting in my lab that contains 1,000.0 mL of gas. If I compress the cylinder and change the volume to 500.0 mL, keeping the temperature constant, what will I expect to see happen to the pressure? • A. The pressure will not change • B. Gases are incompressible, so the volume could not be changed • C. The pressure will double • D. there will be half as much pressure • E. none of the above Feedback: Great! Gas Laws discussed in Chapter 8. Question 10 of 25 4.0 / 4.0 Points `Think back to Lesson one when we talked about density. Now think about it--my kids love balloons, and then are always laying around the house. Suppose one was laying by the window at night when they went to bed, but the next day, when the sun came up, it warmed the gas (air) that was in the balloon. What would be true about the density of the air in the balloon? • A. It will increase. • B. It will remain the same. • C. It will decrease.  • D. it will decrease for a while, then increase E. none of the above Feedback: Great! Gas Laws discussed in Chapter 8. Question 11 of 25 4.0 / 4.0 Points If I have a cylinder that holds 10.7 L of gas at 298 K, how many liters of gas could it hold at 352 K? • A. 12.6 L • B. 578 L • C. 91 L • D. 9.06 L Feedback: Great! Gas Laws discussed in Chapter 8. Question 12 of 25 4.0 / 4.0 Points `Which of these is not a correct statement based on what you know about the kinetic molecular theory as it relates to gases? • A. Gas molecules are held together by strong attractive forces. • B. The size of the gas molecules is nothing compared to the total volume of the gas.   B. 0.085 C. 4.4 • D. 9.5 Feedback: Great! Gas Laws discussed in Chapter 8. Question 15 of 25 4.0 / 4.0 Points `I recently visited the Children's Museum with my kids, and they had a really awesome display about pirates, sunken ships, and artifacts and treasure that had been salvaged from shipwrecks. When they bring these pieces to shore, like the canons, they do so by attaching balloons to them that are inflated under water, and they simply lift the artificats to the surface. If one of those balloons contains 3.00 L of air that has a pressure of 36.74 psi, what is the gas volume (the volume of the balloon) once it floats to the surface? • A. 5.50 L • B. 7.50 L • C. 0.833 L • D. 1.20 L   Feedback: Great! Gas Laws discussed in Chapter 8. Question 16 of 25 4.0 / 4.0 Points You have gas! Well, you have a 450.0 mL sample of gas in a flexible container at 298.15 K. If you heat the gas to a temperature of 315.15 K, what is the new volume in liters (L)? A. 0.4284 L B. 0.4757 L • C. 428.4 L • D. 475.7 L Feedback: Great! Gas Laws discussed in Chapter 8. Question 17 of 25 4.0 / 4.0 Points `I'm looking at the barometer in my lab as I type this question. It says the pressure is 0.905 atm. What is this pressure expressed in torr? • A. 840 • B. 0.905 • C. 13.3   • D. 688 Feedback: Great! Gas Laws discussed in Chapter 8. Question 18 of 25 4.0 / 4.0 Points `I have a test balloon sitting in my underground lair that contains 500 mL of 298.15 °K gas. If I heat the gas in the balloon to 323.15 °K with my laser gun, what will be the new volume of the gas in L? A. 0.542 L B. 0.193 L • C. 0.461 L • D. 1.00 L Feedback: Great! Gas Laws discussed in Chapter 8. Question 19 of 25 4.0 / 4.0 Points I have a sealed cylinder in my lab that contains 250 L of gas. If I keep temperature the same and decrease the volume to 125 L, what should I expect to happen? • A. The pressure will not change  D. 147 atm Feedback: Great! Gas Laws discussed in Chapter 8. Question 22 of 25 4.0 / 4.0 Points `You have been given a 0.325 L canister containing a gas. The pressure gauge on the canister reads 721 mmHg, and the temperature gauge reads 305.15 K. The piston on the canister was pushed to compress the gas to 0.286 L, thereby increasing the pressure to 901 mmHg. What is the new temperature in Celsius? Remember sig figs. • A. 62.4°C • B. 215°C • C. 35.2°C • D. 335°C Feedback: Great! Gas Laws discussed in Chapter 8. Question 23 of 25 0.0 / 4.0 Points `I have a pressure cooker in my underground lair that is brewing a diabolical solution. I set everything up and went upstairs, but forgot to write down the initial temperature. When I came downstairs later to check on it, I see that the pressure gauge shows that the pressure has decreased by 10 times, while the volume increased by 5 times. The temperature now reads - 123.15 °C. What was the starting temperature when I left (in °C)? • A. -198 • B. 75 • C. 27 • D. 300 Feedback: Gas Laws discussed in Chapter 8. Question 24 of 25 4.0 / 4.0 Points `The air that we breathe is actually a mixture of several gases. Of those involved, which is the major component of the mixture? • A. carbon dioxide • B. nitrogen • C. smog • D. oxygen • E. argon Feedback: Great! Gas Laws discussed in Chapter 8. Question 25 of 25 4.0 / 4.0 Points `Suppose you have a fixed container containing 19.08 grams of one of the diatomic (elemental) gases. If the container volume is 3.82 L, and the pressure is 4.78 atm, and the temperature is 100 °C, which gas is it? (R= 0.0821 L atm / mol K )∙ ∙ • A. Br2 • B. O2 • C. H2 • D. F2 • E. not enough information. Feedback: Great! Gas Laws discussed in Chapter 8.