Sage of the Arctic

Pump up the Volume

The apothecary has run over to help the grocer, leaving his teenaged apprentice in charge. The boy is standing outside holding a sheepskin balloon. "Look - Jeremiah - it's filled with Argon! Isn't that awesome?! I have 13.80 moles of pure Argon in here. It is currently at 0°C and the pressure inside is 760 torr.

I want to take it back inside the shop, but it will heat to 20°C, and I fear it will pop. This is one of the season's last sheepskins, and the apothecary will not be happy if I do break it! If the final pressure is 1142 torr, what is the change in volume?"