Each of four flasks is filled with a different gas. Each flask has the same volume, and each is filled to the same pressure, 3.0 atm, at 25 °C. Flask A contains 116 g of air, flask B has 80.7 g of neon, flask C has 16.0 g of helium, and flask C has 160. g of an unknown gas. (a) Do all four flasks contain the same number of gas molecules? If not, which one has the greatest number of molecules? (b) How many times heavier is a molecule of the unknown gas than an atom of helium? (c) In which flask do the molecules have the largest kinetic energy? The highest rms speed?

A certain flexible weather balloon contains helium gas at a volume of 855 L. Initially, the balloon is at sea level where the temperature is 25C and the barometric pressure is 730 torr. The balloon then rises to an altitude of 6000 ft, where the pressure is 605 torr and the temperature is 15C. What is the change in volume of the balloon as it ascends from sea level to 6000 ft?

47 HCl(g) reacts with ammonia gas, NH3(g), to form solid ammonium chloride. If a sample of ammonia occupying 250 mL at 21 C and a pressure of 140 torr is allowed to react with excess HCl, what mass of NH4Cl will form?

Many nitrate salts can be decomposed by heating. For example, blue, anhydrous copper(II) nitrate produces the gases nitrogen dioxide and oxygen when heated. In the laboratory, you find that a sample of this salt produced a 0.195-g mixture of gaseous NO2 and O2 with a total pressure of 725 mm Hg at 35 C in a 125-mL flask (and black, solid CuO was left as a residue). What is the average molar mass of the gas mixture? What are the mole fractions of NO2 and O2 in the mixture? What amount of each gas b in the mixture? Do these amounts reflect the relative amounts of NO2 and O2 expected based on the balanced equation? Is it possible that the fact that some NO2 molecules combine to give N2O4 plays a role? Heating copper(II) nitrate produces nitrogen dioxide and oxygen gas and leaves a residue of copper(ll) oxide.

You have a gas, one of the three known phosphorus-fluorine compounds (PF3, PF3, and P2F4). To find out which, you have decided to measure its molar mass. (a) First, yon determine that the density of the gas is 5.60 g/L at a pressure of 0.971 atm and a temperature of 18.2 C. Calculate the molar mass and identify the compound. (b) To check the results from part (a), you decide to measure the molar mass based on the relative rales of effusion of the unknown gas and CO2. You find that CO2 effuses at a rate of 0.050 mol/min, whereas the unknown phosphorus fluoride effuses at a rate of 0.028 mol/min. Calculate the molar mass of the unknown gas based on these results.

Which of the following statements is(are) true? a. If the number of moles of a gas is doubled, the volume will double, assuming the pressure and temperature of the gas remain constant. b. If the temperature of a gas increases from 25C to 50C, the volume of the gas would double, assuming that the pressure and the number of moles of gas remain constant. c. The device that measures atmospheric pressure is called a barometer. d. If the volume of a gas decreases by one half, then the pressure would double, assuming that the number of moles and the temperature of the gas remain constant.

A sample of natural gas is 85.2% methane, CH4, and 14.8% ethane, C2H6, by mass. What is the density of this mixture at 18C and 771 mmHg?