Bicycle Tutor

hello,
I'm new on this forum and i have a few questions, but my english isn't so well, because i speak dutch, so excuse me for that.
My question:
I had 2 old bikes (X and Y to make it simple) with both 5 gears. The X-bike had a problem with his cassette and Y had not a chain. So I decide to bring over the chain from X to Y, but is this possible? bike Y has a new front sprocket-wheel, but an old cassette.
So is it possible and recommended to change the chain by the old one from X? Or is it better to buy a new chain? and do I have to buy new sprockets then?(or they still available at the stores) and where do i have to keep an eye on, while changing the chains?
thanks and kind regards, filip.

It depends how worn your chain is. Look at the tutorial http://bicycletutor.com/chain-wear/
And of course, how worn the rear sprockets of the thread-on freewheel are (5 speeds on the rear = most probably thread-on freewheel, see
http://sheldonbrown.com/free-k7.html ). So: in principle it can be done. A new chain for a 5 speed is about 10€, on the other hand... a 6 speed freewheel could be compatible, they are sometimes still sold. For compatibility look at the table at http://sheldonbrown.com/freewheels.html

thanks for the reply,
but isn't there a bigger change that the new chain slips over the sprockets, than the older one?

i had forgot something, that is maybe crucial: The chains don't slip over the sprockets, before the change, so I suppose the chains of bike X and Y are in good condition before the chain of bike Y was broken... Maybe this changes something.

Well... the chain and sprockets can be worn to the same degree. Well, yu could just give it a try. If you encounter problems, check for chain and sprocket wear.

ok, in a few weeks I will change it when I have some time, thanks for the answers!