The table below shows temperature and volume data for a set amount of gas at a constant pressure. The third column is the constant for this particular data set and is always equal to the volume divided by the Kelvin temperature. When this data is graphed, the result is a straight line, indicative of a direct relationship, shown in the figure below. Notice that the line goes exactly toward the origin, meaning that as the absolute temperature of the gas approaches zero, its volume approaches zero.
However, when a gas is brought to extremely cold temperatures, its molecules would eventually condense into the liquid state before reaching absolute zero. The temperature at which this change into the liquid state occurs varies for different gases. Charles's Law can also be used to compare changing conditions for a gas. Sign in via your Institution. You could not be signed in, please check and try again.
Sign in with your library card Please enter your library card number. Show Summary Details Overview Charles' law. Charles' law in A Dictionary of Physics 6 Length: words. Charles' law in World Encyclopedia Length: 68 words. All rights reserved. Begin by converting both temperatures to the absolute scale:.
When using Charles' law, remember that volume and Kelvin temperature vary directly; therefore, an increase in either requires a proportional increase in the other. Previous Quiz Boyles Law. The accepted explanation, which James Clerk Maxwell put forward around , is that the amount of space a gas occupies depends purely on the motion of the gas molecules. Under typical conditions, gas molecules are very far from their neighbors, and they are so small that their own bulk is negligible.
They push outward on flasks or pistons or balloons simply by bouncing off those surfaces at high speed. Inside a helium balloon, about 10 24 a million million million million helium atoms smack into each square centimeter of rubber every second, at speeds of about a mile per second!
Both the speed and frequency with which the gas molecules ricochet off container walls depend on the temperature, which is why hotter gases either push harder against the walls higher pressure or occupy larger volumes a few fast molecules can occupy the space of many slow molecules. Specifically, if we double the Kelvin temperature of a rigidly contained gas sample, the number of collisions per unit area per second increases by the square root of 2, and on average the momentum of those collisions increases by the square root of 2.
So the net effect is that the pressure doubles if the container doesn't stretch, or the volume doubles if the container enlarges to keep the pressure from rising.
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