Changes

A '''phase diagram''' is a graphical way of showing the [[physical state]] of a pure substance at varying [[pressure]]s and [[temperature]]s. As seen in the image to the right, a phase diagram is typically represented as a graph with temperature on the [[x-axis]] and pressure on the [[y-axis]].<ref name="atkins">Atkins, Peter and Julio de Paula. ''Physical Chemistry Volume 1, 8e.'' Oxford University Press: 2006.</ref>

A '''phase diagram''' is a graphical way of showing the [[physical state]] of a pure substance at varying [[pressure]]s and [[temperature]]s. As seen in the image to the right, a phase diagram is typically represented as a graph with temperature on the [[x-axis]] and pressure on the [[y-axis]].<ref name="atkins">Atkins, Peter and Julio de Paula. ''Physical Chemistry Volume 1, 8e.'' Oxford University Press: 2006.</ref>

A phase diagram will always have a number of lines on it, representing a phase [[equilibrium]], that is, the set of temperatures and pressures at which one phase is in equilibrium with another phase. These lines are called [[phase boundary|phase boundaries]], and they section the area of the plot into the three phases of [[matter]] ([[solid]], [[liquid]], and [[gas]]) as well as the [[supercritical fluid]] region.<ref name="atkins">

A phase diagram will always have a number of lines on it, representing a phase [[equilibrium]], that is, the set of temperatures and pressures at which one phase is in equilibrium with another phase. These lines are called [[phase boundary|phase boundaries]], and they section the area of the plot into the three phases of [[matter]] ([[solid]], [[liquid]], and [[gas]]) as well as the [[supercritical fluid]] region.<ref name="atkins" />

Along with the phase boundaries, there are two important points on a phase diagram: the [[triple point]] and the [[critical point]]. The triple point is the unique temperature and pressure at which all three phases of matter coexist in equilibrium.

Along with the phase boundaries, there are two important points on a phase diagram: the [[triple point]] and the [[critical point]]. The triple point is the unique temperature and pressure at which all three phases of matter coexist in equilibrium.