Many processes such as the fabrication of integrated circuits are carried out in a vacuum chamber to avoid reaction of the material with oxygen in the atmosphere. It is difficult to routinely lower the pressure in a vacuum chamber below
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Thermodynamics, Statistical Thermodynamics, & Kinetics
- Given that a sample of air is made up of nitrogen, oxygen, and argon in the mole fractions 0.78 N2, 0.21 O2, and 0.010 Ar, what is the density of air at standard temperature and pressure?arrow_forwardOne of the chemical controversies of the nineteenth century concerned the element beryllium (Be). Berzelius originally claimed that beryllium was a trivalent element (forming Be3+ ions) and that it gave an oxide with the formula Be2O3. This resulted in a calculated atomic mass of 13.5 for beryllium. In formulating his periodic table, Mendeleev proposed that beryllium was divalent (forming Be2+ ions) and that it gave an oxide with the formula Be2O3. This assumption gives an atomic mass of 9.0. In 1894, A. Combes (Comptes Rendus 1894, p. 1221) reacted beryllium with the anion C5H7O2and measured the density of the gaseous product. Combess data for two different experiments are as follows: I II Mass 0.2022 g 0.2224 g Volume 22.6 cm3 26.0 cm3 Temperature 13C 17C Pressure 765.2 mm Hg 764.6 mm If beryllium is a divalent metal, the molecular formula of the product will be Be(C5H7O2)2; if it is trivalent, the formula will be Be(C5H7O2)3. Show how Combess data help to confirm that beryllium is a divalent metal.arrow_forwardYou have two pressure-proof steel cylinders of equal volume, one containing 1.0 kg of CO and the other containing 1.0 kg of acetylene, C2H2. (a) In which cylinder is the pressure greater at 25 C? (b) Which cylinder contains the greater number of molecules?arrow_forward
- How does hydraulic fracturing differ from previously used techniques for the recovery of natural gas from the earth?arrow_forwardIn the discussion on the composition of air, mention is made of the fact that water vapor may have a concentration as high as 40,000 ppm. Calculate the partial pressure exerted by water vapor at this concentration. Assume that this represents a situation with 100% humidity. What temperature would be needed to achieve this value? (See Appendix G.)arrow_forwardA gas mixture, that has been formulated to simulate the atmosphere of another planet, contains: 320 mg of methane (CH4), 175 mg of argon (Ar), and 225 mg of nitrogen (N2). The partial pressure of nitrogen at 300 K is 15.2 kPa, calculate the total pressure of the mixture at this temperature.arrow_forward
- A 5.50-mole sample of NH3 gas is kept in a 1.85-L container at 309 K. If the van der Waals equation is assumed to give the correct answer for the pressure of the gas, calculate the percent error made in using the ideal-gas equation to calculate the pressure. (Use a = 4.17 atm·L2·mol−2 and b = 0.0371 L·mol−1 for the van der Waals equation.)arrow_forwardThe composition of the atmosphere is relatively constant, with the exception of humidity; the amount of water vapor in the atmosphere can vary from day to day and location to location. A 1.0-L sample of atmosphere at 298 K is isolated and found to contain the following mixture with the indicated partial pressures: 586.0 mmHg N2, 158.0 mmHg O2, 6.3 mmHg Ar, and 0.9 mmHg of trace gases. Water vapor is also present. The sample has a total pressure of 760.0 mmHg. a. What is the partial pressure? b. What is the mol fraction of H2O?arrow_forwardOn our campus, there are approximately 30.000 students who use 2.5 x 10° kJ of energy per day. Suppose all of that energy comes from the combustion of a carbon- hydrogen-oxygen compound in the presence of excess O2(g). 2.647 g sample of this gaseous carbon-hydrogen-oxygen compound that occupies a volume of 580 mL at 918,6 Torr and 24.00 °C. The products of the combustion of the given amount are 5.059 g CO2(g), 3.106 g H2O(1), and enough heat to raise the temperature of the calorimeter assembly from 24.00 to 38.33 °C. What is the molecular formula of this unknown compound and how many kilograms of this compound are needed to provide enough daily energy to all students on campus? (The heat capacity of the calorimeter is 4.915 kJ/°C.)arrow_forward
- Hydrogen gas is collected over water at 23.5 °C and an atmospheric pressure of 765 mmHg. Calculate the partial pressure of hydrogen gas.arrow_forwardA sample of 3.42 mol of xenon is confined at low pressure in a volume at a temperature of 86 °C. Describe quantitatively the effects of each of the following changes on the pressure, the average kinetic energy per molecule in the gas, and the root-mean-square speed. (a) The temperature is increased to 199 °C (b) The volume is tripled. (c) The amount of xenon is decreased to 1.87 mol Give each answer as a decimal factor of the form: new value factor old value. A factor of 1 means no change. ChangeP KEavgmsarrow_forwardEach sketch below shows a flask with some gas and a pool of mercury in it. The gas is at a pressure of 0.5 atm. A J-shaped tube is connected to the bottom of the flask, and the mercury can freely flow in or out of this tube. (You can assume that there is so much more mercury in the pool than can fit into the tube that even if the J-tube is completely filled, the level of mercury in the pool won't change.) Notice also that in the left sketch the J-tube is open at its other end, so that air from the atmosphere can freely flow. On the other hand, in the right sketch the J-tube is closed at its other end, and you should assume there is no gas between the mercury and the closed end of the tube. To answer this question, you must decide what the mercury level will be when the mercury finally stops flowing in or out of the tube. By moving the sliders back and forth, you'll see different levels of mercury in the J-tube. Select the final correct level for each sketch. A open tube closed tube -…arrow_forward
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