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- How many times larger is carbon dioxide’s contribution to the greenhouse effect compared to methane? (Use radiative forcing values in Table 10.7 to compare the two gases.)
Problem 127
- N2O has a GWP value of 310 and CO2 has a GWP value of 1, but CO2 makes a greater contribution to the greenhouse effect. Explain.
Problem 128
- What are the trends in atmospheric CO2 and CH4 concentrations over the past 150 years and over several hundred thousand years?
Problem 131
- A driver with a nearly empty fuel tank may say she is 'running on fumes.' If a 15.0-gallon automobile gas tank had only gasoline vapor remaining in it, what is the farthest the vehicle could travel if it gets 20.0 miles per gallon on liquid gasoline? Assume the average molar mass of molecules in gasoline is 105 g/mol, the density of liquid gasoline is 0.75 g/mL, the pressure is 743 mm Hg, and the temperature is 25 °C.
Problem 134
Problem 135a,b
Pakistan's K2 is the world's second-tallest mountain, with an altitude of 28,251 ft. Its base camp, where climbers stop to acclimate, is located about 16,400 ft above sea level. (a) Approximate atmospheric pressure P at different altitudes is given by the equation P = e-h/7000, where P is in atmospheres and h is the altitude in meters. What is the approximate atmospheric pressure in mm Hg at K2 base camp? (b) What is the atmospheric pressure in mm Hg at the summit of K2?
Problem 135c
Pakistan's K2 is the world's second-tallest mountain, with an altitude of 28,251 ft. Its base camp, where climbers stop to acclimate, is located about 16,400 ft above sea level. (c) Assuming the mole fraction of oxygen in air is 0.2095, what is the partial pressure of oxygen in mm Hg at the summit of K2?
- Assume that you take a flask, evacuate it to remove all the air, and find its mass to be 478.1 g. You then fill the flask with argon to a pressure of 2.15 atm and reweigh it. What would the balance read in grams if the flask has a volume of 7.35 L and the temperature is 20.0 °C?
Problem 136
Problem 137a
The apparatus shown consists of three temperature-jacketed 1.000-L bulbs connected by stopcocks. Bulb A contains a mixture of H2O(g), CO2(g), and N2(g) at 25 °C and a total pressure of 564 mm Hg. Bulb B is empty and is held at a temperature of -70 °C. Bulb C is also empty and is held at a temperature of -190 °C. The stopcocks are closed, and the volume of the lines connecting the bulbs is zero. CO2 sublimes at -78 °C, and N2 boils at -196 °C.
(a) The stopcock between A and B is opened, and the system is allowed to come to equilibrium. The pressure in A and B is now 219 mm Hg. What do bulbs A and B contain?
Problem 137b
The apparatus shown consists of three temperature-jacketed 1.000-L bulbs connected by stopcocks. Bulb A contains a mixture of H2O(g), CO2(g), and N2(g) at 25 °C and a total pressure of 564 mm Hg. Bulb B is empty and is held at a temperature of -70 °C. Bulb C is also empty and is held at a temperature of -190 °C. The stopcocks are closed, and the volume of the lines connecting the bulbs is zero. CO2 sublimes at -78 °C, and N2 boils at -196 °C.
(b) How many moles of H2O are in the system?
- When solid mercury(I) carbonate, Hg2CO3, is added to nitric acid, HNO3, a reaction occurs to give mercury(II) nitrate, Hg1NO322, water, and two gases A and B: Hg2CO31s2 + HNO31aq2¡ Hg1NO3221aq2 + H2O1l 2 + A1g2 + B1g2 (a) When the gases are placed in a 500.0-mL bulb at 20 °C, the pressure is 258 mm Hg. How many moles of gas are present?
Problem 138
- Consider the combustion reaction of 0.148 g of a hydrocarbon with the formula CnH2n+2 in an excess of O2 within a 400.0-mL steel container. Before the reaction, the gaseous mixture had a temperature of 25.0 °C and a pressure of 2.000 atm. After complete combustion and heat loss, the products and excess O2 had a temperature of 125.0 °C and a pressure of 2.983 atm. (a) What is the formula and molar mass of the hydrocarbon? (b) What are the partial pressures in atmospheres of the reactants? (c) What are the partial pressures in atmospheres of the products and the excess O2?
Problem 139
- A mixture of CS21g2 and excess O21g2 is placed in a 10.0-L reaction vessel at 100.0 °C and a pressure of 3.00 atm. A spark causes the CS2 to ignite, burning it completely, according to the equation CS21g2 + 3 O21g2¡CO21g2 + 2 SO21g2 After reaction, the temperature returns to 100.0 °C, and the mixture of product gases (CO2, SO2, and unreacted O2) is found to have a pressure of 2.40 atm. What is the partial pressure of each gas in the product mixture?
Problem 140
- When 10.0 g of a mixture of Ca1ClO322 and Ca1ClO22 is heated to 700 °C in a 10.0-L vessel, both compounds decompose, forming O21g2 and CaCl21s2. The final pressure inside the vessel is 1.00 atm. (b) What is the mass of each compound in the original mixture?
Problem 141
Problem 141a
When 10.0 g of a mixture of Ca(ClO3)2 and Ca(ClO)2 is heated to 700 °C in a 10.0-L vessel, both compounds decompose, forming O2(g) and CaCl2(s). The final pressure inside the vessel is 1.00 atm. (a) Write balanced equations for the decomposition reactions.
- A 5.00-L vessel contains 25.0 g of PCl3 and 3.00 g of O2 at 15 °C. The vessel is heated to 200.0 °C, and the contents react to give POCl3. What is the final pressure in the vessel, assuming that the reaction goes to completion and that all reactants and products are in the gas phase?
Problem 142
Problem 143a
A steel container with a volume of 500.0 mL is evacuated, and 25.0 g of CaCO3 is added. The container and contents are then heated to 1500 K, causing the CaCO3 to decompose completely, according to the equation CaCO3(s) → CaO(s) + CO2(g). (a) Using the ideal gas law and ignoring the volume of any solids remaining in the container, calculate the pressure inside the container at 1500 K.
Problem 143b
A steel container with a volume of 500.0 mL is evacuated, and 25.0 g of CaCO3 is added. The container and contents are then heated to 1500 K, causing the CaCO3 to decompose completely, according to the equation CaCO3(s) → CaO(s) + CO2(g). (b) Now make a more accurate calculation of the pressure inside the container. Take into account the volume of solid CaO (density = 3.34 g/mL) in the container, and use the van der Waals equation to calculate the pressure. The van der Waals constants for CO2(g) are a = 3.59 (L2-atm)/mol2 and b = 0.0427 L/mol.
- Nitrogen dioxide dimerizes to give dinitrogen tetroxide: 2 NO2(g) ⇌ N2O4(g). At 298 K, 9.66 g of an NO2 and N2O4 mixture exerts a pressure of 0.487 atm in a volume of 6.51 L. What are the mole fractions of the two gases in the mixture?
Problem 144
Problem 145a
An empty 4.00-L steel vessel is filled with 1.00 atm of CH4(g) and 4.00 atm of O2(g) at 300 °C. A spark causes the CH4 to burn completely, according to the equation
CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) ΔH° = -802 kJ
(a) What mass of CO2(g) is produced in the reaction?
Problem 145b
An empty 4.00-L steel vessel is filled with 1.00 atm of CH4(g) and 4.00 atm of O2(g) at 300 °C. A spark causes the CH4 to burn completely, according to the equation
CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) ΔH° = -802 kJ
(b) What is the final temperature inside the vessel after combustion, assuming that the steel vessel has a mass of 14.500 kg, the mixture of gases has an average molar heat capacity of 21 J/(mol·°C), and the heat capacity of steel is 0.449 J/(g·°C)?
Problem 145c
An empty 4.00-L steel vessel is filled with 1.00 atm of CH4(g) and 4.00 atm of O2(g) at 300 °C. A spark causes the CH4 to burn completely, according to the equation
CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) ΔH° = -802 kJ
(c) What is the partial pressure of CO2(g) in the vessel after combustion?
- When a gaseous compound X containing only C, H, and O is burned in O2, 1 volume of the unknown gas reacts with 3 volumes of O2 to give 2 volumes of CO2 and 3 volumes of gaseous H2O. Assume all volumes are measured at the same temperature and pressure. Is the formula you calculated an empirical formula or a molecular formula? Explain.
Problem 146
Problem 146a
When a gaseous compound X containing only C, H, and O is burned in O2, 1 volume of the unknown gas reacts with 3 volumes of O2 to give 2 volumes of CO2 and 3 volumes of gaseous H2O. Assume all volumes are measured at the same temperature and pressure. (a) Calculate a formula for the unknown gas, and write a balanced equation for the combustion reaction.
- Isooctane, C8H18, is the component of gasoline from which the term octane rating derives. (c) What is the volume in liters of CO2 produced at STP?
Problem 147
Problem 147a
Isooctane, C8H18, is the component of gasoline from which the term octane rating derives. (a) Write a balanced equation for the combustion of isooctane to yield CO2 and H2O.
Problem 147b
Isooctane, C8H18, is the component of gasoline from which the term octane rating derives. (b) Assuming that gasoline is 100% isooctane, that isooctane burns to produce only CO2 and H2O, and that the density of isooctane is 0.792 g/mL, what mass of CO2 in kilograms is produced each year by the annual U.S. gasoline consumption of 4.6⨉1010 L?
Problem 147d
Isooctane, C8H18, is the component of gasoline from which the term octane rating derives. (d) How many moles of air are necessary for the combustion of 1 mol of isooctane, assuming that air is 21.0% O2 by volume? What is the volume in liters of this air at STP?
- The Rankine temperature scale used in engineering is to the Fahrenheit scale as the Kelvin scale is to the Celsius scale. That is, 1 Rankine degree is the same size as 1 Fahrenheit degree, and 0 °R = absolute zero. (b) What is the value of the gas constant R on the Rankine scale in 1L ~ atm2>1°R ~ mol2? (c) Use the van der Waals equation to determine the pressure inside a 400.0-mL vessel that contains 2.50 mol of CH4 at a temperature of 525 °R. For CH4, a = 2.253 1L2 ~ atm2>mol2 and b = 0.04278 L>mol.
Problem 148
- Chemical explosions are characterized by the instantaneous release of large quantities of hot gases, which set up a shock wave of enormous pressure (up to 700,000 atm) and velocity (up to 20,000 mi/h). For example, the explosion of nitroglycerin (C3H5N3O9) releases four gases, A, B, C, and D, represented by the equation C3H5N3O9(l) → a A(g) + b B(g) + c C(g) + d D(g). Assume that the explosion of 1 mol (227 g) of nitroglycerin releases gases with a temperature of 1950 °C and a volume of 1323 L at 1.00 atm pressure. (a) How many moles of hot gas are released by the explosion of 0.00400 mol of nitroglycerin? (b) When the products released by the explosion of 0.00400 mol of nitroglycerin were placed in a 500.0-mL flask and the flask was cooled to -10 °C, product A solidified and the pressure inside the flask was 623 mm Hg. How many moles of A were present, and what is its likely identity? (c) When gases B, C, and D were passed through a tube of powdered Li2O, gas B reacted to form Li2CO3. The remaining gases, C and D, were collected in another 500.0-mL flask and found to have a pressure of 260 mm Hg at 25 °C. How many moles of B were present, and what is its likely identity?
Problem 149
Problem 149d
Chemical explosions are characterized by the instantaneous release of large quantities of hot gases, which set up a shock wave of enormous pressure (up to 700,000 atm) and velocity (up to 20,000 mi/h). For example, explosion of nitroglycerin (C3H5N3O9) releases four gases, A, B, C, and D:
n C3H5N3O9(l) a A(g) + b B(g) + c C(g) + d D(g)
Assume that the explosion of 1 mol (227 g) of nitroglycerin releases gases with a temperature of 1950 °C and a volume of 1323 L at 1.00 atm pressure.
(d) When gases C and D were passed through a hot tube of powdered copper, gas C reacted to form CuO. The remaining gas, D, was collected in a third 500.0-mL flask and found to have a mass of 0.168 g and a pressure of 223 mm Hg at 25 °C. How many moles each of C and D were present, and what are their likely identities?