Hoppers in Survival

[Josue_Gordon]

I've heard from many players that there is a limit on how many hoppers you can use in a chunk, and there is a special hopper too. Can anybody explain to me who plays survival regularly, what the limit is on hoppers per chunk, and explain what these special hoppers are and how to obtain them? And also, why do hoppers work so slowly, and what was the reason behind putting such a limit?