National League for Nursing (NLN PAX) Practice Exam

What process is exemplified by the dispersion of ammonia vapor throughout a closed room?

1. Osmosis

2. Diffusion

3. Filtration

4. Active transport

The correct answer is: Diffusion

The correct answer is diffusion because this process involves the movement of molecules from an area of higher concentration to an area of lower concentration until equilibrium is achieved. In the case of ammonia vapor in a closed room, the ammonia molecules naturally spread out throughout the available space due to their kinetic energy and the random motion of gas particles. This occurs without the need for energy input or assistance, which is characteristic of diffusion. Osmosis, on the other hand, specifically refers to the movement of water across a semi-permeable membrane and is not applicable in this context, as ammonia vapor is a gas and does not move through a membrane. Filtration involves separating substances based on particle size and is typically used in liquid or solid contexts, while active transport is a process requiring energy to move substances against their concentration gradient, which does not happen in the case of gas dispersion. Thus, diffusion accurately describes the phenomenon of ammonia vapor spreading throughout the room.