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문제 77
Hydrogen gas (a potential future fuel) can be formed by the reaction of methane with water according to the equation: CH4(g) + H2O(g) → CO(g) + 3 H2(g) In a particular reaction, 25.5 L of methane gas (measured at a pressure of 732 torr and a temperature of 25 °C) mixes with 22.8 L of water vapor (measured at a pressure of 702 torr and a temperature of 125 °C). The reaction produces 26.2 L of hydrogen gas at STP. What is the percent yield of the reaction?
문제 78
Ozone is depleted in the stratosphere by chlorine from CF3Cl according to this set of equations:
CF3Cl + UV light → CF3 + Cl
Cl + O3 → ClO + O2
O3 + UV light → O2 + O
ClO + O → Cl + O2
What total volume of ozone at a pressure of 25.0 mmHg and a temperature of 225 K is destroyed when all of the chlorine from 15.0 g of CF3Cl goes through 10 cycles of the given reactions?
문제 79
Chlorine gas reacts with fluorine gas to form chlorine trifluoride. Cl2(g) + 3 F2(g) → 2 ClF3(g) A 2.00-L reaction vessel, initially at 298 K, contains chlorine gas at a partial pressure of 337 mmHg and fluorine gas at a partial pressure of 729 mmHg. Identify the limiting reactant. Determine the theoretical yield of ClF3 in grams.
문제 80
Carbon monoxide gas reacts with hydrogen gas to form methanol. CO(g) + 2 H2(g) → CH3OH(g) A 1.50-L reaction vessel, initially at 305 K, contains carbon monoxide gas at a partial pressure of 232 mmHg and hydrogen gas at a partial pressure of 397 mmHg. Identify the limiting reactant. Determine the theoretical yield of methanol in grams.
문제 81
Consider a 1.0-L sample of helium gas and a 1.0-L sample of argon gas, both at room temperature and atmospheric pressure. a. Do the atoms in the helium sample have the same average kinetic energy as the atoms in the argon sample?
문제 82a
A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and xenon. a. Which of the two gases exerts the greater partial pressure?
문제 82b,d
A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and xenon. b. The molecules or atoms of which gas have the greater average velocity? d. If a small hole were opened in the flask, which gas effuses more quickly?
문제 82c
A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and xenon. c. The molecules of which gas have the greater average kinetic energy?
문제 83a
Calculate the root mean square velocity of F2, Cl2, and Br2 at 298 K.
문제 83b
Calculate the kinetic energy of F2, Cl2, and Br2 at 298 K.
문제 83c
Calculate the root mean square velocity and kinetic energy of F2, Cl2, and Br2 at 298 K. Rank these three halogens with respect to their rate of effusion.
문제 84
Calculate the root mean square velocity and kinetic energy of CO, CO2, and SO3 at 298 K. Which gas has the greatest velocity? The greatest kinetic energy? The greatest effusion rate?
문제 85
We separate U-235 from U-238 by fluorinating a sample of uranium to form UF6 (which is a gas) and then taking advantage of the different rates of effusion and diffusion for compounds containing the two isotopes. Calculate the ratio of effusion rates for 238UF6 and 235UF6. The atomic mass of U-235 is 235.054 amu and that of U-238 is 238.051 amu.
문제 86
Calculate the ratio of effusion rates for Ar and Kr.
문제 87
A sample of neon effuses from a container in 76 seconds. The same amount of an unknown noble gas requires 155 seconds. Identify the second gas.
문제 88
A sample of N2O effuses from a container in 42 seconds. How long will it take the same amount of gaseous I2 to effuse from the same container under identical conditions?
문제 89
The graph shows the distribution of molecular velocities for two different molecules (A and B) at the same temperature. Which molecule has the higher molar mass? Which molecule has the higher rate of effusion?
문제 90
The graph shows the distribution of molecular velocities for the same molecule at two different temperatures (T1 and T2). Which temperature is greater? Explain.
문제 91
Which postulate of the kinetic molecular theory breaks down under conditions of high pressure? Explain.
- Which postulate of the kinetic molecular theory breaks down under conditions of low temperature?
문제 92
문제 93
Use the van der Waals equation and the ideal gas equation to calculate the volume of 1.000 mol of neon at a pressure of 500.0 atm and a temperature of 355.0 K. Explain why the two values are different. (Hint: One way to solve the van der Waals equation for V is to use successive approximations. Use the ideal gas law to get a preliminary estimate for V.)
문제 94
Use the van der Waals equation and the ideal gas equation to calculate the pressure exerted by 1.000 mol of Cl2 in a volume of 5.000 L at a temperature of 273.0 K. Explain why the two values are different.
문제 95
Modern pennies are composed of zinc coated with copper. A student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coating (to expose the underlying zinc). The student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the HCl (the copper remains undissolved): Zn(s) + 2 HCl(aq)¡ H2( g) + ZnCl2(aq) The student collects the hydrogen produced over water at 25 °C. The collected gas occupies a volume of 0.899 L at a total pressure of 791 mmHg. Calculate the percent zinc (by mass) in the penny. (Assume that all the Zn in the penny dissolves.)
문제 96
A 2.85-g sample of an unknown chlorofluorocarbon decomposes and produces 564 mL of chlorine gas at a pressure of 752 mmHg and a temperature of 298 K. What is the percent chlorine (by mass) in the unknown chlorofluorocarbon?
문제 97
The mass of an evacuated 255 mL flask is 143.187 g. The mass of the flask filled with 267 torr of an unknown gas at 25 °C is 143.289 g. Calculate the molar mass of the unknown gas.
- When a 118-mL flask is evacuated, it has a mass of 97.129 g. Upon filling it with 768 torr of helium gas at 35 °C, the mass increases to 97.171 g. Based on this information, can we determine if the helium gas was pure?
문제 98
문제 99
A gaseous hydrogen- and carbon-containing compound is decomposed and found to contain 82.66% carbon and 17.34% hydrogen by mass. The mass of 158 mL of the gas, measured at 556 mmHg and 25 °C, was 0.275 g. What is the molecular formula of the compound?
문제 100
A gaseous hydrogen- and carbon-containing compound is decomposed and found to contain 85.63% C and 14.37% H by mass. The mass of 258 mL of the gas, measured at STP, was 0.646 g. What is the molecular formula of the compound?
- Consider the reaction: 2 NiO(s) → 2 Ni(s) + O2(g). If O2 is collected over water at 40.0 °C and a total pressure of 745 mmHg, what volume of gas is collected for the complete reaction of 24.78 g of NiO?
문제 101
문제 102
Consider the reaction: 2 Ag2O(s) → 4 Ag(s) + O2(g) If this reaction produces 15.8 g of Ag(s), what total volume of gas can be collected over water at a temperature of 25 °C and a total pressure of 752 mmHg?