A sample of N2(g) effuses through a tiny hole in 38 seconds. What must be the molar mass of a gas that requires 64 seconds to effuse under identical conditions? (N – 14)

Ammonia gas is synthesized by combining hydrogen and nitrogen: 3 H2(g) + N2(g) 2 NH3(g) (a) If you want to produce 562 g of NH3, what volume of H2 gas, at 56 C and 745 mm Hg, is required? (b) Nitrogen for this reaction will be obtained from air. What volume of air, measured at 29 C and 745 mm Hg pressure, will be required to provide the nitrogen needed to produce 562 g of NH3? Assume the sample of air contains 78.1 mole % N2.

Liquid oxygen was first prepared by heating potassium chlorate, KClO3, in a closed vessel to obtain oxygen at high pressure. The oxygen was cooled until it liquefied. 2KClO3(s)2KCl(s)+3O2(g) If 171 g of potassium chlorate reacts in a 2.70-L vessel, which was initially evacuated, what pressure of oxygen will be attained when the temperature is finally cooled to 25C? Use the preceding chemical equation and ignore the volume of solid product.

A flask is first evacuated so that it contains no gas at all. Then, 2.2 g of CO2 is introduced into the flask. On warming to 22 C, the gas exerts a pressure of 318 mm Hg. What is the volume of the flask?

A chemist weighed out 5.14 g of a mixture containing unknown amounts of BaO(s) and CaO(s) and placed the sample in a 1.50-L flask containing CO2(g) at 30.0C and 750. torr. After the reaction to form BaCO3(s) and CaCO3(s) was completed, the pressure of CO2(g) remaining was 230. torr. Calculate the mass percentages of CaO(s) and BaO(s) in the mixture.

The distribution of molecular velocities in a sample of helium is shown in Figure 9.34. If the sample is cooled, will the distribution of velocities look more like that of H2 or of H2O? Explain your answer.

52 If tetraborane, B4H10, is treated with pure oxygen, it burns to give B2O3 and H2O: 2B4H10(s)+11O2(g)4B2O3(s)+10H2O(g) If a 0.050-g sample of tetraborane burns completely in O2, what will be the pressure of the gaseous water in a 4.25-L flask at 30.0 C?

82 Why do heavier gases move more slowly than light gases at the same temperature?

Two identical He-filled balloons, each with a volume of 20 L, are allowed to rise into the atmosphere. One rises to an altitude of 3000 m while the other rises to 6000 m. a Assuming that the balloons are at the same temperature, which balloon has the greater volume? b What information would you need in order to calculate the volume of each of the balloons at their respective heights?

A 1.0-L flask contains 10.0 g each of O2 and CO2 at 25 C. (a) Which gas has the greater partial pressure, O2 or CO2, or are they the same? (b) Which molecules have the greater rms speed, or are they the same? (c) Which molecules have the greater average kinetic energy, or are they the same?