Questions from Previous Chemistry 115 Exams Gases

Questions from Previous Chemistry 115 Exams Gases -...

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Questions from Previous Chemistry 115 Exams Gases 1. Kirsten is in her lab, and reacts two unknown gases (A(g) and B(g)) to get nitrogen dioxide (NO 2 ). Using her data, she is able to write the following balanced equation: 2A(g) + B(g) --> 2NO 2 (g) If she started with 8 L of A(g) and 3 L of B(g), how many liters of NO 2 (g) would she get? [Assume everything is at STP.] a. 2 L b. 3 L c. 4 L d. 6 L e. 8 L 2. Calculate the number of kilograms of O 2 (g) that can be stored in a compressed gas chamber with a volume of 40 L when the cylinder is filled at 150 atm and 21 o C. a. 4.0 kg b. 8.0 kg c. 4000 kg d. 8000 kg e. Not enough information 3. Yesterday, Jason had a sample of helium indoors (T = 23 o C) in a sealed container, with a pressure of 760 mm Hg. He got bored and took the container outside, where the temperature was a blistering 35 o C. He calculated the new pressure to be 750 mm Hg. Jason knew that this answer was not correct because: a. T K = T o C + 273.15 b. Equal volumes of gas have the same number of moles. c. P is proportional to n d. P is proportional to T e. He forgot to convert his temperature to K and the pressure should have decreased even more.
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4. Suppose that Quebec had managed to succeed from Canada and became an independent country. Just to be difficult, they decreed that they will only measure pressure in mm Hg and volume in cm 3 . What value for R, the ideal gas constant, would students in Quebec use when solving the ideal gas solution? a. 7.6 x 10 5 b. 6.23 x 10 4 c. 8.14 d. 2.78 e. 0.082 5. Consider two 1 L flasks, one containing O 2 , the other containing He, each at STP. Which of the following statements is NOT true regarding these gases? a. Each flask contains the same number of atoms or molecules b. The gases in each flask have the same average kinetic energy c. The gases in each flask have the same density d. The pressure in each flask is the same e. The temperature of the gases in each flask is 273.15 K. 6. The density of N 2 at STP is: a. 1.25 g/L b. 1.04 g/L c. 0.625 g/L d. 0.0625 g/L e. 5.43 mg/L 7. A 1.00 L flask containing 450 torr of H 2 is connected to and mixed with a second flask with a volume of 0.500 L containing 250 torr N 2 . What is the final pressure of the resulting mixed gas system? a. 250 torr b. 383 torr c. 450 torr d. 575 torr e. it cannot be determined 8. A piston is used to compress a gas from 1.0 atm to 3.5 atm. If the volume changes from 1.5 L to 0.75 L, what is the final temperature, if it started at 300 K?
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a. 1050 K b. 700 K c. 525 K d. 300 K e. 150K 9. 2.00 g of sucrose is combusted in excess oxygen. What is the volume of dry CO 2 that is formed at 1 atm pressure and 37 o C? (MW sucrose = 342.3 g/mol) C 12 H 22 O 11 + 12O 2 --> 12CO 2 + 11H 2 O a. 22.4 L b. 10.4 L c. 1.78 L d. 0.545 L e. 0.148 L 10. Which of the following statements regarding the kinetic-molecular theory of ideal gases is incorrect? a.
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Questions from Previous Chemistry 115 Exams Gases -...

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