What is the significance of crossing a line in a phase diagram

The green line divides the solid and liquid phases and represents melting solid to liquid and freezing liquid to solid. The blue divides the liquid and gas phases, represents vaporization liquid to gas and condensation gas to liquid. There are also two important points on the diagram, the triple point and the critical point.

The triple point represents the combination of pressure and temperature that facilitates all phases of matter at equilibrium. With most substances, the temperature and pressure related to the triple point lie below standard temperature and pressure and the pressure for the critical point lies above standard pressure. Therefore at standard pressure as temperature increases, most substances change from solid to liquid to gas, and at standard temperature as pressure increases, most substances change from gas to liquid to solid.

However for other substances, notably water, the line slopes to the left as the diagram for water shows. This indicates that the liquid phase is more dense than the solid phase. This phenomenon is caused by the crystal structure of the solid phase. In the solid forms of water and some other substances, the molecules crystalize in a lattice with greater average space between molecules, thus resulting in a solid with a lower density than the liquid.

Because of this phenomenon, one is able to melt ice simply by applying pressure and not by adding heat. Moving about the phase diagram reveals information about the phases of matter. Moving along a constant temperature line reveals relative densities of the phases.

When moving from the bottom of the diagram to the top, the relative density increases. Moving along a constant pressure line reveals relative energies of the phases. When moving from the left of the diagram to the right, the relative energies increases.

Imagine a substance with the following points on the phase diagram: a triple point at. The solid liquid line is "normal" meaning positive sloping. For this, complete the following:. Rank the states with respect to increasing density and increasing energy. One would see a super-critical fluid, when approaching the point, one would see the meniscus between the liquid and gas disappear.

The substance would begin as a gas and as the pressure increases, it would compress and eventually solidify without liquefying as the temperature is below the triple point temperature. Draw a generic phase diagram and label its importan….

What useful information can be obtained from studyi…. What useful information can be obtained from the st…. Describe the information that a phase diagram supplies.

Explain what the triple point and the critical point on a phase diagram repr…. How do …. What are the most important differences between the phase diagram of a pure …. Share Question Copy Link. Report Question Typo in question. Answer is wrong. Video playback is not visible.

Audio playback is not audible. Answer is not helpful. Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry deals with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds. Chemistry also involves understanding the properties and interactions of individual atoms and molecules for use in larger-scale applications. In chemistry and physics, matter is any substance that has mass and takes up space by having volume.

All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, "matter" generally includes atoms and anything made up of them, and any particles and objects that act as if they have both rest mass and volume. However it does not include massless particles such as photons, or other energy phenomena or waves such as light or sound. Matter exists in various states known as phases that are defined by various physical properties, such as state of matter, phase, shape, and density.

The Standard Model of particle physics and the general theory of relativity describe fundamental particles and the fundamental forces acting between them that control the structure and dynamics of matter. Click 'Join' if it's correct. Jennifer R. Chemistry 2 months ago. View Full Video Already have an account? As shown on the phase diagram, the alloy is, at the given temperature, a mixture of alpha and liquid phases - but what are their exact compositions at this temperature?

An isothermal constant temperature line through the alloy's position on the phase diagram when it is in a two phase field, intersecting the two adjacent solubility curves , is called a tie line yes, that's the horizontal yellow line on the diagram. For a cooling alloy at composition C o and temperature T x , tie lines may be used to answer questions such as: what phases are present? To answer "what are their compositions?

To answer the last question "if the temperature is reduced to T y , how do the compositions of the two phases vary? Now that we know the compositions of the two phases, we need to find how much of each phase exists at the given temperature. The ratio of the two phases present can be found by using the lever rule.