That's false. Because, the molecules in a solid are compacted too tightly together that they don't have all that extra space that a gas would. Molecules in a gas would have more thermal energy because they have all that space to move around in. The more they move around, the hotter it gets. The less that they move around, and the more that they put and packed together, the colder it's going to be.
Hope this helped you!! (:
You will have excess O2. The ideal gas law dictates that all other variables kept the same, equal volume means equal number of moles.