CHM 101 American University of Sharjah General Chemistry Questions i need help in solving a hw ill put the question in the pdf files below but no need to s

CHM 101 American University of Sharjah General Chemistry Questions i need help in solving a hw ill put the question in the pdf files below but no need to solve all the question.

solve only the questions under the bold problem, and not all of them just the question numbers that are with black.

#for example

Problem

4.7

4.8(red)

4.9.

#for example u just need to solve 4.7 and 4.9.

hand written if u can 9:57
< Chemistry_12th_Edition_by_Chang_a... • 5.74 • 5.75 REVIEW STRA 5.65 State Dalton's law of partial pressures and explain what mole fraction is. Does mole fraction have units? 5.66 A sample of air contains only nitrogen and oxygen gases whose partial pressures are 0.80 atm and 0.20 atm, respectively. Calculate the total pressure and the mole fractions of the gases. Problems • 5.67 A mixture of gases contains 0.31 mol CH 0.25 mol C, H. and 0.29 mol CH3. The total pressure is 1.50 atm. Calculate the partial pressures of the gases. A 2.5-L flask at 15°C contains a mixture of N, He, and Ne at partial pressures of 0.32 atm for N2, 0.15 atm for He, and 0.42 atm for Ne. (a) Calculate the total A sample of ammonia (NH) gas is completely de- composed to nitrogen and hydrogen gases over heated iron wool. If the total pressure is 866 mmHg, calculate the partial pressures of N, and H. Consider the three gas containers shown here. All of them have the same volume and are at the same temperature. (a) Which container has the smallest mole fraction of gas A (blue sphere)? (b) Which container has the highest partial pressure of gas B (green sphere)? • 5.68 ) (in www.pdflobby.com Questions & Problems 219 5.76 The volume of the box on the right is twice that of the box on the left. The boxes contain helium at- oms (red) and hydrogen molecules (green) at the same temperature. (a) Which box has a higher total pressure? (b) Which box has a lower partial pres- sure of helium? 5.87 only 0.72 percent. To separate it from the more abundant U isotope, uranium is first converted to UF, which is easily vaporized above room temperature. The mixture of the 2SUF, and 238UF gases is then subjected to many stages of effusion. Calculate the separation factor, that is, the enrich- ment of 235U relative to 238U after one stage of effusion. A gas evolved from the fermentation of glucose is found to effuse through a porous barrier in 15.0 min. Under the same conditions of temperature and pressure, it takes an equal volume of N, 12.0 min to effuse through the same barrier. Calculate the molar mass of the gas and suggest what the gas might be. Nickel forms gaseous compound of the formula Ni(CO),. What is the value of x given the fact that under the same conditions of temperature and pres- sure, methane (CH) effuses 3.3 times faster than the compound? 5.88 Kinetic Molecular Theory of Gases Review Questions 5.77 What are the basic assumptions of the kinetic mo- lecular theory of gases? How does the kinetic molecular theory explain Boyle's law, Charles law, Avogadro's law, and Dalton's law of partial pressures? 5.78 What does the Maxwell speed distribution curve tell us? Does Maxwell's theory work for a sample of 200 molecules? Explain. • 5.79 Which of the following statements is correct? (a) Heat is produced by the collision of gas mol- ecules against one another. (b) When a gas is heated, the molecules collide with one another more often. 5.80 What is the difference between gas diffusion and effusion? State Graham's law and define the terms in Equation (5.17). Deviation from Ideal Behavior Review Questions 5.89 Cite two pieces of evidence to show that gases do not behave ideally under all conditions. 5.90 Under what set of conditions would a gas be ex- pected to behave most ideally? (a) High temperature and low pressure, (b) high temperature and high pressure, (c) low temperature and high pressure, (d) low temperature and low pressure. 5.91 Shown here are plots of PV/RT against P for one mole of a nonideal gas at two different temperatures. Which curve is at the higher temperature? PY 10 Problems 5.81 Compare the root-mean-square speeds of O, and UF at 65°C • 5.82 The temperature in the stratosphere is -23°C. Cal- culate the root-mean-square speeds of N, 02, and o molecules in this region. 5.83 The average distance traveled by a molecule between successive collisions called mean free path. For a given amount of a gas, how does the mean free path of a gas depend on (a) density, (b) temperature at constant volume, (c) pressure at constant tempera- ture, (d) volume at constant temperature, and (e) size of the atoms? 5.84 At a certain temperature the speeds of six gaseous molecules in a container are 2.0 m/s 2.2 m/s 2.6 m/s 2.7 m/s, 3.3 m/s, and 3.5 m/s. Calculate the root- mean-square speed and the average speed of the mol- ecules. These two average values are close to each other, but the root-mean-square value is always the larger of the two. Why? 5.85 Based on your knowledge of the kinetic theory of gases, derive Graham's law Equation (5.17)]. • 5.86 The 235U isotope undergoes fission when bombarded with neutrons. However, its natural abundance is 5.92 (a) A real gas is introduced into a flask of volume V. Is the corrected volume of the gas greater or less than V? (b) Ammonia has a larger a value than neon does (see Table 5.4). What can you conclude about the relative strength of the attractive forces between molecules of ammonia and between atoms of neon? www.pdflobby.com 220 Chapter 5. Gases Problems • 5.93 Using the data shown in Table 5.4, calculate the pressure exerted by 2.50 moles of CO2 confined in a volume of 5.00 L at 450 K. Compare the pressure with that predicted by the ideal gas equation. 5.94 At 27°C, 10.0 moles of a gas in a 150.1 container exert a pressure of 130 atm. Is this an ideal gas! completion.) (b) At temperatures above 43°C, the pressure of the gas is observed to increase much more rapidly than predicted by the ideal gas equa- tion. Explain. 5.103 The partial pressure of carbon dioxide varies with seasons. Would you expect the partial pressure in the be higher in the summer or winter? Explain. 9:57 < Chemistry_12th_Edition_by_Chang_a... • 5.56 In alcohol fermentation, yeast converts glucose to ethanol and carbon dioxide: CH,0 (3) 2C,H,OH(+200 (8) 5.46 5.57 • 5.47 ESCO the harmful radiation from the sun. Typically, the temperature and pressure of ozone in the strato- sphere are 250 K and 1.0 x 10 atm, respectively. How many ozone molecules are present in 1.0 L of air under these conditions? Assuming that air contains 78 percent N, 21 percent 02 and 1 percent Ar, all by volume, how many mol- ecules of each type of gas are present in 1.0 L of air at STP? A 2.10-L vessel contains 4.65 g of a gas at 1.00 atm and 27.0°C. (a) Calculate the density of the gas in grams per liter. (b) What is the molar mass of the gas? Calculate the density of hydrogen bromide (HBr) gas in grams per liter at 733 mmHg and 46°C. A certain anesthetic contains 64.9 percent C, 13.5 per- cent H, and 21.6 percent o by mass. At 120°C and 750 mmHg, 1.00 L of the gaseous compound weighs 2.30 g. What is the molecular formula of the compound? If 5.97 g of glucose are reacted and 1.44 L of CO2 gas are collected at 293 K and 0.984 atm, what is the percent yield of the reaction? A compound of P and F was analyzed as follows: Heating 0.2324 g of the compound in a 378-cm container turned all of it to gas, which had a pressure of 97.3 mmHg at 77°C. Then the gas was mixed with calcium chloride solution, which turned all of the F to 0.2631 g of CaF, Determine the molecular formula of the compound. A quantity of 0.225 g of a metal M (molar mass = 27.0 g/mol) liberated 0.303 L of molecular hydrogen (measured at 17°C and 741 mmHg) from an excess of hydrochloric acid. Deduce from these data the corresponding equation and write formulas for the oxide and sulfate of M. • 5.48 • 5.58 • 5.49 www.pdflobby.com 218 Chapter 5. Gases • 5.59 • 5.69 • 5.60 • 5.61 • 5.70 5.62 • 5.71 What is the mass of the solid NH CI formed when 73.0 g of NH, are mixed with an equal mass of HCI? What is the volume of the gas remaining, measured at 14.0°C and 752 mmHg? What gas is it? Dissolving 3.00 g of an impure sample of cal- cium carbonate in hydrochloric acid produced 0.656 L of carbon dioxide (measured at 20.0°C and 792 mmHg). Calculate the percent by mass of calcium carbonate in the sample. State any as- sumptions. Calculate the mass in grams of hydrogen chloride produced when 5.6 L of molecular hydrogen mea- sured at STP react with an excess of molecular chlo- rine gas, Ethanol (C,H,OH) burns in air; CH,OH(1) + O2(g) ?? CO2(8) + H2O(1) Balance the equation and determine the volume of air in liters at 35.0°C and 790 mmHg required to burn 227 g of ethanol. Assume that air is 21.0 per- cento, by volume. (a) What volumes (in liters) of ammonia and oxy. gen must react to form 12.8 L of nitric oxide according to the equation at the same temperature and pressure? 4NH,(g) + 50,(8) — 4NO(g) + 6H2O(g) (b) What volumes in liters) of propane and water vapor must react to form 8.96 L of hydrogen accord- ing to the equation at the same temperature and pressure? CH (8) + 3H,0(8) ? 3CO(g) + 7H,(8) A 4.00-8 sample of Fes containing nonsulfide im- purities reacted with HCl to give 896 mL of HS at 14°C and 782 mmHg. Calculate mass percent purity of the sample. 5.63 pressure of the mixture. (b) Calculate the volume in liters at STP occupied by He and Ne if the N, is removed selectively Dry air near sea level has the following composition by volume: N, 78,08 percent: 0,, 20.94 percent; Ar, 0.93 percent; CO2, 0.05 percent. The atmospheric pressure is 1.00 atm. Calculate (a) the partial pressure of each gas in atm and (b) the concentration of each gas in moles per liter at O'C. (Hint: Because volume is proportional to the number of moles present, mole fractions of gases can be expressed as ratios of vol- umes at the same temperature and pressure.) A mixture of helium and neon gases is collected over water at 28.0°C and 745 mmHg. If the partial pressure of helium is 368 mmHg, what is the par- tial pressure of neon? (Vapor pressure of water at 28°C = 28.3 mmHg.) A piece of sodium metal reacts completely with water as follows: 2Na(s) + 2H2O(l) — 2NaOH(aq) + H (8) The hydrogen gas generated is collected over water at 25.0°C. The volume of the gas is 246 mL mea- sured at 1.00 atm. Calculate the number of grams of sodium used in the reaction. (Vapor pressure of water at 25°C -0.0313 atm.) A sample of zinc metal reacts completely with an excess of hydrochloric acid: Zn(s) + 2HCl(aq) ? ZnCl(aq) + H (8) The hydrogen gas produced is collected over water at 25.0°C using an arrangement similar to that shown in Figure 5.15. The volume of the gas is 7.80 L, and the pressure is 0.980 atm. Calculate the amount of zinc metal in grams consumed in the reaction. (Vapor pressure of water at 25°C = 23.8 mmHg.) Helium is mixed with oxygen gas for deep-sea divers. Calculate the percent by volume of oxygen gas in the mixture if the diver has to submerge to a depth where the total pressure is 4.2 atm. The partial pressure of oxygen is maintained at 0.20 atm at this depth. A sample of ammonia (NH) gas is completely de- composed to nitrogen and hydrogen gases over heated iron wool. If the total pressure is 866 mmHg, calculate the partial pressures of N, and H. Consider the three gas containers shown here. All of them have the same volume and are at the same temperature. (a) Which container has the smallest mole fraction of gas A (blue sphere)? (b) Which container has the highest partial pressure of gas B (green sphere)? • 5.72 5.64 • 5.73 • 5.74 Dalton's Law of Partial Pressures Review Questions 5.65 State Dalton's law of partial pressures and explain what mole fraction is. Does mole fraction have units? 5.66 A sample of air contains only nitrogen and oxygen gases whose partial pressures are 0.80 atm and 0.20 atm, respectively. Calculate the total pressure and the mole fractions of the gases. • 5.75 Problems • 5.67 A mixture of gases contains 0.31 mol CH 0.25 mol CH., and 0.29 mol CH3. The total pressure is 1.50 atm. Calculate the partial pressures of the gases. • 5.68 A 2.5-L flask at 15°C contains a mixture of N, He, and Ne at partial pressures of 0.32 atm for N, 0.15 atm for He, and 0.42 atm for Ne. (a) Calculate the total (1) www.pdflobby.com Questions & Problems 219 5.76 The volume of the box on the right is twice that of the box on the left. The boxes contain helium at oms (red) and hydrogen moes WC erature ( Which hoy has higher total only 0.72 percent. To separate it from the more abundant 218U isotope, uranium is first converted www.ch is easily vaporized above room temperature The mixture of the 235UE. and 238UE. 9:57 < Chemistry_12th_Edition_by_Chang_a... What units are normally used to express the density of gases? (a) (b) • 5.19 • 5.32 Problems • 5.31 A sample of nitrogen gas kept in a container of vol- ume 23 L and at a temperature of 32°C exerts a pressure of 4.7 atm. Calculate the number of moles of gas present. Given that 6.9 moles of carbon monoxide gas are present in a container of volume 30.4 L, what is the pressure of the gas (in atm) if the temperature is 62°C? • 5.33 What volume will 5.6 moles of sulfur hexafluoride (SF) gas occupy if the temperature and pressure of the gas are 128°C and 9.4 atm? • 5.34 A certain amount of gas at 25°C and at a pressure of 0.800 atm is contained in a glass vessel. Suppose that the vessel can withstand a pressure of 2.00 atm. How high can you raise the temperature of the gas without bursting the vessel? A gas occupying a volume of 725 mL at a pressure of 0.970 atm is allowed to expand at constant tem- perature until its pressure reaches 0.541 atm. What is its final volume? At 46°C a sample of ammonia gas exerts a pressure of 5.3 atm. What is the pressure when the volume of the gas is reduced to one-tenth (0.10) of the original value at the same temperature? The volume of a gas is 5.80 L, measured at 1.00 atm. What is the pressure of the gas in mmHg if the vol- ume is changed to 9.65 L? (The temperature remains constant.) • 5.20 • 5.21 www.pdflobby.com Questions & Problems 217 • 5.35 5.50 5.51 A compound has the empirical formula SF At 20°C, 0.100 g of the gaseous compound occupies a volume of 22.1 mL and exerts a pressure of 1.02 atm. What is the molecular formula of the gas? What pressure will be required for neon at 30°C to have the same density as nitrogen at 20°C and 1.0 atm? The density of a mixture of fluorine and chlorine gases is 1.77 g/L at 14°C and 0.893 atm. Calculate the mass percent of the gases. 5.36 5.52 A gas-filled balloon having a volume of 2.50 L at 1.2 atm and 25°C is allowed to rise to the strato- sphere (about 30 km above the surface of Earth), where the temperature and pressure are -23°C and 3.00 X 10 atm, respectively. Calculate the final volume of the balloon. The temperature of 2.5 L of a gas initially at STP is raised to 250°C at constant volume. Calculate the final pressure of the gas in atm. The pressure of 6.0 L of an ideal gas in a flexible container is decreased to one-third of its original pressure, and its absolute temperature is de- creased by one-half. What is the final volume of the gas? A gas evolved during the fermentation of glucose (wine making) has a volume of 0.78 L at 20.1°C and 1.00 atm. What was the volume of this gas at the fermentation temperature of 36.5°C and 1.00 atm • 5.37 Gas Stoichiometry Problems • 5.53 Consider the formation of nitrogen dioxide from nitric oxide and oxygen: • 5.38 2NO(g) + O2(g) ? 2NO,(8) pressure? • 5.39 • 5.54 An ideal gas originally at 0.85 atm and 66°C was allowed to expand until its final volume, pressure, and temperature were 94 mL, 0.60 atm, and 45°C, respectively. What was its initial volume? Calculate its volume (in liters) of 88.4 g of CO2 If 9.0 L of NO are reacted with excess O, at STP, what is the volume in liters of the NO2 produced? Methane, the principal component of natural gas, is used for heating and cooking. The combustion process is 5.40 STP CH (8) +202(g) -CO2(g) + 2H2O(1) • 5.41 • 5.42 • 5.55 If 15.0 moles of CH, are reacted, what is the volume of CO2 (in liters) produced at 23.0°C and 0.985 atm? When coal is burned, the sulfur present in coal is converted to sulfur dioxide (SO2), which is respon- sible for the acid rain phenomenon. • 5.43 S(s) + 0,(8) - SO,(8) 5.44 • 5.45 • 5.56 A gas at 772 mmHg and 35.0°C occupies a volume of 6.85 L. Calculate its volume at STP. Dry ice is solid carbon dioxide. A 0.050-g sample of dry ice is placed in an evacuated 4.6-L vessel at 30°C. Calculate the pressure inside the vessel after all the dry ice has been converted to CO2 gas. At STP, 0.280 L of a gas weighs 0.400 g. Calculate the molar mass of the gas. At 741 torr and 44°C, 7.10 g of a gas occupy a vol- ume of 5.40 L. What is the molar mass of the gas? ume of 5.40 L. What is the Ozone molecules in the stratosphere absorb much of the harmful radiation from the sun. Typically, the temperature and pressure of ozone in the strato- sphere are 250 K and 1.0 X 10 atm, respectively. How many ozone molecules are present in 1.0 L of air under these conditions? Assuming that air contains 78 percent N, 21 percent 02, and 1 percent Ar, all by volume, how many mol- ecules of each type of gas are present in 1.0 L of air at STP? A 2.10-L vessel contains 4.65 g of a gas at 1.00 atm and 27.0°C. (a) Calculate the density of the gas in grams per liter. (b) What is the molar mass of the gas? Calculate the density of hydrogen bromide (HB) gas in grams per liter at 733 mmHg and 46°C. A certain anesthetic contains 64.9 percent C, 13.5 per- cent H. and 21.6 percent o by mass. At 120°C and 750 mmHg, 1.00 L of the gaseous compound weighs 2.30 g. What is the molecular formula of the compound? 5.46 5.57 If 2.54 kg of Sare reacted with oxygen, calculate the volume of So, gas (in mL) formed at 30.5°C and 1.12 atm. In alcohol fermentation, yeast converts glucose to ethanol and carbon dioxide: CH,0 () 42CH,OH(1) + 200 (8) If 5.97 g of glucose are reacted and 1.44 L of CO2 gas are collected at 293 K and 0.984 atm, what is the percent yield of the reaction? A compound of P and F was analyzed as follows: Heating 0.2324 g of the compound in a 378-cm container turned all of it to gas, which had a pressure of 97.3 mmHg at 77°C. Then the gas was mixed with calcium chloride solution, which turned all of the F to 0.2631 g of CaF, Determine the molecular formula of the compound. A quantity of 0.225 g of a metal M (molar mass = 27.0 g/mol) liberated 0.303 L of molecular hydrogen (measured at 17°C and 741 mmHg) from an excess of hydrochloric acid. Deduce from these data the corresponding equation and write formulas for the oxide and sulfate of M. • 5.47 • 5.48 • 5.58 • 5.49 www.pdflobby.com 218 Chapter 5. Gases • 5.59 What is the mass of the solid NH.Cl formed when 73.0 g of NH, are mixed wi HCI? What is the volume of the gas remaining. pressure of the mixture. (b) Calculate the volume in by He and Ne if the N, is removed selectively. 9:56 < Chemistry_12th_Edition_by_Chang_a... Vacuum (a) (b) 5.9 5.10 What is the difference between a gas and a vapor? At 25°C, which of the following substances in the gas phase should be properly called a gas and which should be called a vapor: molecular nitrogen (N2), mercury? If the maximum distance that water may be brought up a well by a suction pump is 34 ft (10.3 m), how is it possible to obtain water and oil from hundreds of feet below the surface of Earth? Problems • 5.17 A gaseous sample of a substance is cooled at con- stant pressure. Which of the following diagrams best represents the situation if the final temperature is www.pdflobby.com 216 Chapter 5. Gases • 5.22 (a) above the boiling point of the substance and (b) below the boiling point but above the freezing point of the substance? • 5.23 • 5.24 (a) (b) (c) (d) A sample of air occupies 3.8 L when the pressure is 1.2 atm. (a) What volume does it occupy at 6.6 atm? (b) What pressure is required in order to compress it to 0.075 L? (The temperature is kept constant.) A 36.4-L volume of methane gas is heated from 25°C to 88°C at constant pressure. What is the final volume of the gas? Under con... Purchase answer to see full attachment