Final answer:
To identify the gas above the liquid in the cup, you can use a flaming splint and a glowing splint. If the gas supports combustion, it is oxygen.
Step-by-step explanation:
The gas above the liquid in the cup can be identified using a flaming splint and a glowing splint. If the gas supports combustion and allows the flaming splint to burst into full flame, it is oxygen. If the gas extinguishes the glowing splint, it is a gas that does not contain oxygen. Oxygen is the only gas that will support combustion.