Deck 16: Chemical and Phase Equilibrium

Question 1

If the equilibrium constant for the reaction C + O₂ $\rightarrow$ CO₂ is K, the equilibrium constant for the reaction 2CO₂ $\rightarrow$ 2C + 2O₂ at the same temperature is

A)1/K
B)1/(2K)
C)2K
D)K²
E)1/K²

Answer 1

1/K²

Question 2

If the equilibrium constant for the reaction H₂ + ½O₂ $\rightarrow$ H₂O is K, the equilibrium constant for the reaction H₂O + 2N₂ $\rightarrow$ H₂ + ½O₂ + 2N₂ at the same temperature is

A)1/K
B)1/(K + 2)
C)4K
D)K
E)1/K²

Answer 2

1/K

Question 3

The equilibrium constant for the reaction CO + ½O₂ $\rightarrow$ CO₂ at 1 atm and 1500°C is given to be K. Of the reactions given below, all at 1500°C, the reaction that has a different equilibrium constant is

A)CO + ½O₂ $\rightarrow$ CO₂ at 5 atm,
B)2 CO + O₂ $\rightarrow$ 2CO₂ at 1 atm,
C)CO + O₂ $\rightarrow$ CO₂+ ½O₂ at 2 atm,
D)CO + ½O₂ + 3N₂ $\rightarrow$ CO₂+ 3N₂ at 5 atm,
E)CO + ½O₂ + 3N₂ $\rightarrow$ CO₂+ 3N₂ at 1 atm,

Answer 3

2 CO + O₂ $\rightarrow$ 2CO₂ at 1 atm,

Question 4

Of the reactions given below, the reaction whose equilibrium composition at a specified temperature is not affected by pressure is

A)S + O₂ $\rightarrow$ SO₂
B)CO + ½O₂ $\rightarrow$ CO₂
C)H₂ + O₂ $\rightarrow$ 2HO
D)H₂ $\rightarrow$ 2H
E)all of the above.

Question 5

Of the reactions given below, the reaction whose number of moles of products increases by the addition of inert gases into the reaction chamber at constant pressure and temperature is

A)S + O₂ $\rightarrow$ SO₂
B)CO + ½O₂ $\rightarrow$ CO₂
C)H₂ + O₂ $\rightarrow$ 2HO
D)H₂ $\rightarrow$ 2H
E)none of the above.

Question 6

Moist air is heated to a very high temperature. If the equilibrium composition consists of H₂O, O₂, N₂, H₂, and NO, the number of equilibrium constant relations needed to determine the equilibrium composition of the mixture is

A)1
B)2
C)3
D)4
E)5

Question 7

Propane C₃H₈ is burned with air, and the combustion products consist of CO₂, CO, H₂O, O₂, N₂, and NO. The number of equilibrium constant relations needed to determine the equilibrium composition of the mixture is

A)1
B)2
C)3
D)4
E)5

Question 8

Consider a gas mixture that consists of three components. The number of independent variables that need to be specified to fix the state of the mixture is

A)1
B)2
C)3
D)4
E)5

Question 9

The value of Henry's constant for CO₂ gas dissolved in water at 290 K is 12.8 MPa. Consider water exposed to atmospheric air at 90 kPa that contains 1.5 percent CO₂ by volume. Under phase equilibrium conditions, the mole fraction of CO₂ gas dissolved in water at 290 K is

A)1.06x10^-4
B)3.2x10^-4
C)9.80x10^-4
D)173x10^-4
E)13.5x10^-4

Question 10

The solubility of nitrogen gas in rubber at 25°C is 0.00156 kmol/m³.bar. When phase equilibrium is established, the density of nitrogen in a rubber piece placed in a nitrogen gas chamber at 800 kPa is

A)0.012 kg/m³
B)0.35 kg/m³
C)0.30 kg/m³
D)0.56 kg/m³
E)0.78 kg/m³