Suppose you and your friend are on the moon. Will you be able to hear any sound produced by your friend?

No, I would not be able to hear any sound produced by my friend on the moon. Sound requires a medium, such as air, to travel through, and the moon lacks a significant atmosphere. Since there is no air or medium to transmit sound waves, any sounds my friend makes would not be heard by me on the moon. In the absence of a medium for sound propagation, communication through sound waves is not possible in the vacuum of space.