Video Transcript
What effect will increasing the temperature have on the rate of diffusion? (A) The rate of diffusion will decrease. (B) The rate of diffusion will decrease, then increase. (C) The rate of diffusion will increase. (D) The rate of diffusion will increase, then decrease. Or (E) the rate of diffusion will stay the same.
This question is asking about the process of diffusion, which is defined as a gas or liquid spreading out into another gas or liquid. A simple example of diffusion is a drop of ink entering a glass of water and spreading out to turn the entire glass a certain color. This question is asking about the effect of temperature on the rate of diffusion. Or in other words, if we make the temperature hotter, will the particles diffuse or spread out faster or slower?
To incorporate all of the possible choices, the rate could also stay the same or change more than once. So how does temperature affect the rate of diffusion? The key relationship to understand for this problem is that a higher temperature results in more kinetic energy in the particles which causes them to defuse faster. The particles involved will move randomly through space, colliding with the surrounding particles. At a higher temperature, the particles will have more kinetic energy, which means that they move more quickly and bump into the other particles with more momentum.
The increase in speed will result in the particles moving and defusing more quickly. Unless we change the temperature again, the increased rate of diffusion will remain. So our answer is choice (C), the rate of diffusion will increase. Hotter things diffuse faster. That’s why, for example, a freshly baked piece of pie will be more fragrant than the whipped cream on top. Scent molecules emanating from the hot slice of pie will reach our noses quicker and at greater distances than the scent molecules emanating from the whipped cream.
What about the example that we brought up earlier? How will the temperature affect the rate of diffusion when a drop of ink is dropped into a glass of water. Well, ink dropped into a glass of hot water will spread out faster than ink dropped into a glass of cold water. We can observe this by noting that the cold glass of water will take longer to completely change color. So as we can see, it’s true in theory, and it’s true in a couple of real-life examples. Increasing the temperature will cause the rate of diffusion to increase.
