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31st Oct 2019 @ 2 min read
The graph of Boyle's law is known as pressure-volume graph or PV curve. It is as follows:
As observed from the graph above, pressure increases with a decrease in volume, and vice versa. Thus, pressure is inversely proportional to volume. Other parameters (temperature and amount of gas) are constant in the graph above.
Volume is on the x-axis and pressure, on the y-axis. The equation of the curve is PV = k, which is the equation of Boyle's law. The curve is hyperbolic in nature having two asymptotes: P = 0 (horizontal) and V = 0 (vertical).
Note: An asymptote is a line or curve such that the distance between it and a given curve tends to zero as x and/or y coordinates tends to infinity.
As volume tends to positive infinity, pressure tends to zero, and we get the horizontal asymptote, P = 0.
When volume approaches zero, pressure approaches infinity, and it results in the vertical asymptote, V = 0.
Graphs of Boyle's law can be plotted at different temperatures. Each curve in the graphs below is at a constant temperature and such curves are called isotherms.
The above graph is a pressure-volume graph plotted at three different temperatures (T1, T2, and T3). As observed from the graph, with an increase in temperature, curves shift upwards. This is because of increase in the value of k.
The graph of pressure vs inverse volume is a straight line passing through the origin and having the positive slope, k.
The graph above is a straight line parallel to the x-axis. This proves the product of pressure and volume at a constant temperature and amount of gas is constant. The lines in the graph are independent of volume (or pressure).
The equation of Boyle's law is PV = k. Taking the logarithm to both sides.
The plots are a straight line with the y-intercept of log k.
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