1. Yes, it is possible for ice to turn directly. If pressure is low enough water molecules with enough energy can escape the ice crystals because of low pressure and sublime. 2. No, it does not violate the gas laws. With the increase in the number of moles, there should be a corresponding increase in pressure and volume. 3. Atmospheric pressured acts on objects in all directions. The water is kept inside the glass atmospheric pressure is cancelling out the force due to the mass of the water. Unless the water is displaced with air, it won’t fall out.
b. H2 , because the greater number of molecules (moles) impart more pressure. c. BONUS if you tried. PH2 = Ptot (nH2 / nO2 + nH2) and PO2 = Ptot (nO2 / nO2 + nH2)