I did research on the measurement and modeling of diffusion of acid gases in alkanolamine solutions. It's like when you put a drop of food coloring in a glass of water. Even if it is left perfectly still, it will slowly spread out or diffuse until it is all the same. That's the simple way to explain it. That makes it quite a bit more complicated because you can have ten or so different type molecules continually changing while they diffuse through each other.
Acid gases are gases which form acids in water.
Carbon dioxide is all around us, we breathe it out and produce it as a combustion product. Hydrogen sulfide on the other hand smells like rotten eggs and is extremely poisonous. That makes it more fun to work with. Alkanolamines are a type of amine often used to absorb acid gases. This information is needed to calculate the specifications for absorption columns used in refining systems to clean natural gas streams of these acid gases once the gas has been removed from the ground and before it is delivered to your house.