Final answer:
To determine if oxygen is present in a splint test, observe the behavior of a wooden splint when inserted into a gas. If the splint continues to glow when inserted, it indicates the presence of oxygen. If it ceases to glow, there is no oxygen.
Step-by-step explanation:
The presence of oxygen in a splint test can be determined by observing the behavior of a wooden splint when inserted into a gas. Oxygen is the only gas that supports combustion. If a wooden splint that is lit on fire continues to glow when inserted into a gas, it indicates the presence of oxygen. On the other hand, if the splint immediately ceases to glow, it suggests that there is no oxygen in the gas.