Suppressors are legal, yes.
Silencers are not legal in the state of Iowa. Currently there are 39 out of 50 states that individuals, trusts and corporations can legally own silencers.
Yes, silencers are legal in Nevada (assuming they are correctly registered with the ATF)
Yes. Must be registered with the Federal BATF, but state legal.
No. New York bans them just like they ban machineguns / full autos.
They are under the prohibited status, meaning you need a prohibited license to own one.
Because they could easily be used as firearm silencers.
No. They trap and slow the release of gasses after the gun fires.
No
Typically steel or aluminum
According to what I found (a cursory search on the internet) silencers are legal in Kansas as of sometime in 2007 or 2008. Silencers are still regulated by federal law. To purchase one legally, you must go through a class 3 dealer.
The local police can assist you.
Silencers are illegal in SOME states for the general public, but only a few. See link below