Question

at STP which type of substance would contain 6.022*10^23 particles in a 22.4-L sample?

Answer 1

before you let people tell you the answer, why don't you guess? what's avogadro's number? how big is 22.4 liters? which state of matter (solid/liquid/gas/?) is the substance likely to be in?

Answer 2

I did know how to do it. i just forget and need a refresher.

Answer 3

it's usually a bad idea to let people tell you what's right without giving it some initial effort (looking it up in the book, thinking out loud, etc.) it's impossible to learn something well in this way.

why don't you give it a try? don't worry about looking bad. we've all looked bad before.