The chain in use on modern bicycles has a 1/2" pitch, which is ANSI standard #40, where the 4 indicates the pitch of the chain in eighths of an inch, and metric #8, where the 8 indicates the pitch in sixteenths of an inch. (from experience metric and standard chains are interchangeable as long as the width is right)
Chain comes in either 3/32", 1/8", 5/32" or 3/16" roller widths: 5/32" is used on cargo bikes and trikes, 1/8" with the common low cost coaster (back pedal brake) bike, hub and fixed gearing and on track bicycles, and 3/32" with the derailleur gears most commonly fitted on racing, touring and mountain bikes.
CHAIN PITCH #35 & #41 this should help with the #35 chain questions, centrifugal clutch info and goodies