Which of the following is true about fuel cells? a. they only produce energy in short bursts. b. they are inexpensive. c. they have never been built or used. d. they can be designed so that they emit no pollutants.

How does the value of the equilibrium constant show that a reaction reaches equilibrium very quickly? (a) the equilibrium constant is large. (b) the equilibrium constant is small. (c) the equilibrium constant is zero. (d) the value of the equilibrium constant does not show how quickly a reaction comes to equilibrium.