CHEM1011 Lecture Notes - Lecture 5: Diffraction, Refraction, Mole Fraction

A vessel contained N_2, Ar, He, and Ne. The total pressure in the vessel is 2.49 atm. The partial pressure of nitrogen, argon, and helium were 440, 486, and 376 torr, respectively. The partial pressure of neon in the vessel was ___ atm A) 0.495 B) 0.777 C) 0.287 D) 0.245 E) 1.00 In a gas mixture of He, Ne, and Ar with a total pressure of 15.00 atm, the mole fraction of Ar is ___ when the partial pressures of He and Ne are 3.00 and 2.00 atm, respectively. A) 0.75 B) 0.238 C) 0.667 D) 0.405 E) 0.500 The volume of 2.498 g of an ideal gas) was 754 mL at 1.98 atm and 62 degree C. The gas A) Ne B) SO_2 C) NH_3 D) NO_2 E) SO_3 A sample of oxygen gas was found to effuse at a rate 3.316 times faster than that of an unknown gas. The molecular weight of the unknown gas is g/mol. A) 288 B) 12 8 C) 352 D) 16 E) 512 A real gas differs from an ideal gas in that the molecules of a real gas_ A) have strong attraction for one another and occupy finite volumes B) have perfectly elastic collisions C) have a molecular weight of zero D) have no kinetic energy L) have an average molecular mass

5. Hydrogen gas (2.02 g/mol) can be produced from the reaction of methane (16.05 g/mol) and water vapor (18.02 g/mol) according to the following reaction equation: CHdg) + H2O(g) → CO(g) + 3 Hag) If98 g CHs react with excess H20 at 733 K and 0.762 atm, what volume of H2 gas will form? Question 4 5. At a given temperature, nitrogen gas effuses 0.378 times faster than the gas X, what is the molar mass of X? Question5 5. Tungsten hexafluoride is one of the heaviest gases known, with a molar mass of 297.9 g/mol. At a given temperature, how long will it take WFs to cover the distance H2 can travel in 33 seconds? Question 6 5. You wish to measure the changes in pressures of gases during the course of a reaction using a closed-end mercury manometer. Suppose 720 mmHg N204 is allowed to react to form NO2 according to the reaction, N204g)- 2 NO2(g). The total pressure you measure, as the reaction proceeds, is the sum of the pressures of N204 and NO2 present. When the total pressure is 1150 mmHg, what is the pressure of N204? (mmHg) Question 7 5. The diffusion rate of H2 in a lecture hall was found to be 22.0 m/sec at 25°C. How long will it take poisonous HCN gas to diffuse 9 m in the same room? (s) Question 8 5. During the decomposition of CaCO,(s) into Ca0(s) and CO.(g), 115.0 ml of gas is collected by the displacement of water in a flask at 21°C with an atmospheric pressure of 735 mmHg. The vapor pressure of water at this temperature is 18.7 mmHg. What was the mass of oxygen collected? (mg)