Which statement describes one characteristic of an operating electrolytic cell?
(1) it produces electrical energy.
(2) it requires an external energy source.
(3) it uses radioactive nuclides.
(4) it undergoes a spontaneous redox reaction.

Which statement is true according to the kinetic theory? a. molecules of different gases with the same mass and temperature always have the same average density. b. molecules of different gases with the same mass and temperature always have the same average volume. c. molecules of different gases with the same mass and temperature always have the same pressure. d. molecules of different gases with the same mass and temperature always have the same molecular mass. e. molecules of different gases with the same mass and temperature always have the same average kinetic energy.