Which of the following is an example of gas diffusion?

• A. Air being pumped into a bicycle tire
• B. The scent of perfume spreading throughout a room
• C. Oxygen dissolving in water
• D. Water vapor condensing on a cold window

Answer: (B)

Verified step by step guidance

1. Understand the concept of gas diffusion: Diffusion is the process by which molecules spread from an area of higher concentration to an area of lower concentration due to their random motion.
2. Analyze each option to see if it involves the movement of gas molecules spreading out naturally without external force:
3. 1. Air being pumped into a bicycle tire involves forced movement of gas molecules, not natural spreading, so it is not diffusion.
4. 2. The scent of perfume spreading throughout a room is an example of gas molecules moving from a high concentration (near the perfume) to lower concentration areas in the room, which matches the definition of diffusion.
5. 3. Oxygen dissolving in water is a process of gas dissolving into a liquid, not diffusion of gas through air.
6. 4. Water vapor condensing on a cold window is a phase change from gas to liquid, not diffusion.