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 9.0 x 10-11 Torr. Part B Correct What fraction of the gas phase molecules initially present for 1.0 atm in the chamber are present at 1.0 × 10-10 Torr? Express fraction to two significant figures.

perform stoichiometric ca1cu1uions for reactions involving gases as reactants or products.

How would the use of a volatile liquid affect the measurement of a gas using open-ended manometers vs. closed-end manometers?

At elevated temperatures, sodium chlorate decomposes to produce sodium chloride and oxygen gas. A 0.8765-g sample of impure sodium chlorate was heated until the production of oxygen gas ceased. The oxygen gas collected over water occupied 57.2 mL at a temperature of 22C and a pressure of 734 torr. Calculate the mass percent of NaClO3 in the original sample. (At 22C the vapor pressure of water is 19.8 torr.)

One 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.

You 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?

Sulfur dioxide reacts with oxygen in the presence of plati- num to give sulfur trioxide: 2 SO2(g) + O2(g) → 2 SO3(g) Suppose that at one stage in the reaction, 26.0 mol SO2, 83.0 mol O2, and 17.0 mol SO3 are present in the reaction vessel at a total pressure of 0.950 atm. Calculate the mole fraction of SO3 and its partial pressure.

A 2.00 L reaction container at 25.0 °C contains CO2 (g) and O2 (g). The total pressure of the gases in the container was 656 torr and the mole fraction of CO2 is 0.245.    A)Calculate the partial pressure of oxygen gas in the mixture. B)Calculate the mass of oxygen gas in the mixture (in g). C)Which gas will rise to the top of the container? Explain your answer.

A gas sample is observed to exert a pressure of 600 tor when confined to a 10.0 L vessel at 27ºC. What will be its pressure in kPa when the gas is transferred to an 8.0 L vessel at 300K?

How many moles of krypton gas must be added to a 250 ml incandescent light bulb to yield a gas pressure of 200 kPa at 20.0o