Can I reconnect a normal chain with a quick link I have just mounted a chain, but I did it wrong and need to take it off. I have no more joining pins, but I have some spare quick links for this chain. Will they work even though the chain didn't come with them?
It came with a joining pin. I am asking because I don't want cut the chain for two inner ends and then realise it won't work.
Also, how can I mount them, if possible?
You did not mention the type of your chain, but yes, quicklinks normally also work for other brands. SRAM quicklinks are known to work for Shimano chains etc.
Be aware that you must use 9-speed quicklinks for a 9-speed chain and similar. The widths differ so the the number of speeds must match.
You can solve some problems with wrong chain installation also by opening the derailleur cage (small screws), reinserting the chain, and closing agai. Under tension it could be tricky, though. Definitely take the chain off the crank first.