AS Chemistry, CuSo4 + Fe

We did a reaction in class that I have to write up.
CuSO4 (aq) + Fe (s)
The Fe was iron fillings.

Observations-
The grey fillings turned orange/ pink (Cu)
Bubbles from fillings
Warmed up
Blue solution turned lighter and eventually clear
Bad smell

I assume that FeSO4 and Cu were produced, because Fe is more reactive and displaced the SO4

But what was the gas produced? Or is this just trapped air?

Thanks

Is this your chemistry practical? what board are you on?