Sun October 16, 2011 By: Ankit Khound

Which phenomenon is involved in the following: A balloon is filled with enough air and tied tightly. After some days, the size of the balloon decreases. Is it diffusion or effusion? Why?

Expert Reply
Tue October 18, 2011
Diffusion describes the spread of particles through random motion from regions of higher concentration to regions of lower concentration.
effusion is the process in which individual molecules flow through a hole without collisions between molecules. This occurs if the diameter of the hole is considerably smaller than the mean free path of the molecules.
In the above there is no whole in the ballon hence it clearly shows that it is diffusion.
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