Charles' and Boyle's Laws explained
I really hate Charles and Boyels' laws! Is there anyway to help me understand
it more thoroughly?
Answer Charles' law and Boyle's law are both examples of "empirical gas laws."
What this means is that they wre originally discovered by doing careful
measurements of a gas' pressure P, temperature T and volume V. By holding
the temperature of the gas fixed and varying its volume, Boyle observed that
the larger the volume got, the lower the pressure of the gas became. This inverse
relations ship, P = K/V, is Boyle's law. Similarly, by holding P fixed and
varying V, Charles found that the larger the volume got, the higher the
temperature became: this direct relationship, V = bT, is Charles' law.
We can understand these experiments on a molecular level. Boyle's law works
because the speed with which molecules move depends only on the temperature,
not on P and V. So in creasing the volume decreases the number of collisions
of gas molecules with the walls per unit time, which decreases the pressure.
Charles' law is harder. By increasing T we increase the average energy of
all the molecules. Yet, we are forcing the pressure to remain fixed, which
must mean that the molecules are not colliding with the walls as often. So
an increase in V is necessary to decrease the number of collisions per unit time.
I hope that this helps!
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Update: June 2012