Thermodynamics

822 | Thermodynamics16–102 The equilibrium constant for the reaction H 2 12 O 2 S H 2 O at 1 atm and 1500°C is given to be K. Of thereactions given below, all at 1500°C, the reaction that has adifferent equilibrium constant is(a) H 2 1 2 O 2 S H 2 Oat 5 atm(b) 2H 2 O 2 → 2H 2 Oat 1 atm(c) H 2 O 2 S H 2 O 1 2 O 2at 2 atm(d) H 2 1 2 O 2 3N 2 S H 2 O 3N 2 at 5 atm(e) H 2 1 2 O 2 3N 2 S H 2 O 3N 2 at 1 atm16–103 Of the reactions given below, the reaction whoseequilibrium composition at a specified temperature is notaffected by pressure is(a) H 2 1 2 O 2 S H 2 O(b) CO 1 2 O 2 S CO 2(c) N 2 O 2 → 2NO(d) N 2 → 2N(e) all of the above.16–104 Of the reactions given below, the reaction whosenumber of moles of products increases by the addition ofinert gases into the reaction chamber at constant pressure andtemperature is(a) H 2 1 2 O 2 S H 2 O(b) CO 1 2 O 2 S CO 2(c) N 2 O 2 → 2NO(d) N 2 → 2N(e) all of the above.16–105 Moist air is heated to a very high temperature. Ifthe equilibrium composition consists of H 2 O, O 2 ,N 2 , OH,H 2 , and NO, the number of equilibrium constant relationsneeded to determine the equilibrium composition of themixture is(a) 1 (b) 2 (c) 3 (d) 4 (e) 516–106 Propane C 3 H 8 is burned with air, and the combustionproducts consist of CO 2 , CO, H 2 O, O 2 ,N 2 , OH, H 2 , andNO. The number of equilibrium constant relations needed todetermine the equilibrium composition of the mixture is(a) 1 (b) 2 (c) 3 (d) 4 (e) 516–107 Consider a gas mixture that consists of three components.The number of independent variables that need to bespecified to fix the state of the mixture is(a) 1 (b) 2 (c) 3 (d) 4 (e) 516–108 The value of Henry’s constant for CO 2 gas dissolvedin water at 290 K is 12.8 MPa. Consider waterexposed to atmospheric air at 100 kPa that contains 3 percentCO 2 by volume. Under phase equilibrium conditions, themole fraction of CO 2 gas dissolved in water at 290 K is(a) 2.3 10 4 (b) 3.0 10 4 (c) 0.80 10 4(d) 2.2 10 4 (e) 5.6 10 416–109 The solubility of nitrogen gas in rubber at 25°C is0.00156 kmol/m 3 · bar. When phase equilibrium is established,the density of nitrogen in a rubber piece placed in a nitrogengas chamber at 800 kPa is(a) 0.012 kg/m 3 (b) 0.35 kg/m 3 (c) 0.42 kg/m 3(d) 0.56 kg/m 3 (e) 0.078 kg/m 3Design and Essay Problems16–110 An article that appeared in the Reno Gazette-Journal on May 18, 1992, quotes an inventor as saying thathe has turned water into motor vehicle fuel in a breakthroughthat would increase engine efficiency, save gasoline, andreduce smog. There is also a picture of a car that the inventorhas modified to run on half water and half gasoline. Theinventor claims that sparks from catalytic poles in the convertedengine break down the water into oxygen and hydrogen,which is burned with the gasoline. He adds thathydrogen has a higher energy density than carbon and thehigh-energy density enables one to get more power. Theinventor states that the fuel efficiency of his car increasedfrom 20 mpg (miles per gallon) to more than 50 mpg ofgasoline as a result of conversion and notes that the conversionhas sharply reduced emissions of hydrocarbons, carbonmonoxide, and other exhaust pollutants.Evaluate the claims made by the inventor, and write areport that is to be submitted to a group of investors who areconsidering financing this invention.16–111 Automobiles are major emitters of air pollutantssuch as NO x , CO, and hydrocarbons HC. Find out the legallimits of these pollutants in your area, and estimate the totalamount of each pollutant, in kg, that would be produced inyour town if all the cars were emitting pollutants at the legallimit. State your assumptions.