If it's expired, the most it can do is protect you from Tear gas. it is ineffective for NBC purposes. go and buy a real one. search 40mm gas mask filter.
also, this doesnt look like the one from an israeli mask. it looks more like the Russian GP5 filter from the cold war
I'm not sure, but I think it depends on what chemicals are in the air. If I have to use this I would use it once and discard. Safety is something you want to be sure of. I bought extra, so my mask never becomes useless.