What describes diffusion?

What describes diffusion?

• A. The spread of particles from high to low concentration
• B. Movement of particles against concentration gradient
• C. Movement only when external energy is applied
• D. Diffusion occurs only in solids

Answer: (A)

Diffusion is the passive spread of particles from regions of higher concentration to regions of lower concentration because molecules are in constant random motion. This random movement causes more particles to move into the less crowded area, and the overall distribution becomes uniform without anyone supplying energy. It happens in gases, liquids, and, given enough time, even in solids, and its rate increases with higher temperature, smaller particle size, and greater concentration differences. A common example is the scent of perfume spreading through a room. If movement required energy or happened only against a gradient, we’d be describing active transport, not diffusion, and diffusion isn’t limited to solids.

Diffusion is the passive spread of particles from regions of higher concentration to regions of lower concentration because molecules are in constant random motion. This random movement causes more particles to move into the less crowded area, and the overall distribution becomes uniform without anyone supplying energy. It happens in gases, liquids, and, given enough time, even in solids, and its rate increases with higher temperature, smaller particle size, and greater concentration differences. A common example is the scent of perfume spreading through a room. If movement required energy or happened only against a gradient, we’d be describing active transport, not diffusion, and diffusion isn’t limited to solids.