liquid

Examples of liquid in the following topics:

• Liquid to Gas Phase Transition

  • Vaporization of a sample of liquid is a phase transition from the liquid phase to the gas phase.
  • Vaporization of a sample of liquid is a phase transition from the liquid phase to the gas phase.
  • The vapor pressure of a liquid is determined by the attractive forces that act on the molecules at the surface of a liquid.
  • Also, since the bubble is formed within the liquid, the hydrostatic pressure of the overlaying liquid will add to this effect.
  • Run the model, then heat the liquids.

• Capillary Action

  • If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by cohesion within the liquid) and adhesive forces between the liquid and container act together to lift the liquid.
  • The height (h) of a liquid column is given by:
  • Capillary action acts on concave menisci to pull the liquid up, increasing the favorable contact area between liquid and container, and on convex menisci to pull the liquid down, reducing the amount of contact area.
  • When considering how liquids will behave on surfaces, if the liquid molecules are strongly attracted to the solid molecules then the liquid drop will completely spread out on the solid surface.
  • The rise or fall of liquids in a capillary tube depends upon the interactions between the tube and the liquid.

• Surface Tension

  • Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force.
  • Therefore, gases are compressible while liquids are very nearly not.
  • Surface tension is responsible for the shape of a liquid droplet.
  • Different liquids and solutions have different surface tensions.
  • For a needle floating on the surface of a liquid, the downward force of the needle's weight is balanced by the upward forces of surface tension from the liquid. 

• Supercritical Fluids

  • It can effuse through solids (like a gas), and dissolve materials (like a liquid).
  • The system consists of 2 phases in equilibrium, a dense liquid and a low density gas.
  • The dry ice melts under high pressure, and forms a liquid and gas phase.
  • When the vessel is heated, the CO2 becomes supercritical -- meaning the liquid and gas phases merge together into a new phase that has properties of a gas, but the density of a liquid.
  • Supercritical fluids have properties between those of a gas and a liquid.

• Liquid to Solid Phase Transition

  • All known liquids, except helium, freeze when the temperature is low enough.
  • (Liquid helium remains a liquid at atmospheric pressure even at absolute zero, and can be solidified only under higher pressure.)
  • Most liquids freeze by crystallization, the formation of a crystalline solid from the uniform liquid.
  • Matter exists as solids, liquids and gases, and can change state between these.
  • The model shows a liquid material on the left (small atoms).

• The Structure and Properties of Water

  • In nature, water exists in the liquid, solid, and gaseous states.
  • Well-defined boundaries between solid and liquid, solid and gas, and liquid and gas.
  • The solid form of most substances is denser than the liquid phase; therefore, a block of a given solid will generally sink in its corresponding liquid.
  • However, a block of ice floats in liquid water because ice is less dense than liquid water.
  • Liquid water is most dense at 4 degrees Celsius.

• Three States of Matter

  • The three states of matter are the distinct physical forms that matter can take: solid, liquid, and gas.
  • A solid can transform into a liquid through melting, and a liquid can transform into a solid through freezing.
  • This process of a liquid changing to a gas is called evaporation.
  • It can also exist in equilibrium with a liquid (or solid), in which case the gas pressure equals the vapor pressure of the liquid (or solid).
  • In this state, the distinction between liquid and gas disappears.

• Solid to Gas Phase Transition

  • Sublimation is the phase transition from the solid to the gaseous phase, without passing through an intermediate liquid phase.
  • Sublimation is the process of transformation directly from the solid phase to the gaseous phase, without passing through an intermediate liquid phase.
  • In these cases, the transition from the solid to the gaseous state requires an intermediate liquid state.
  • This is because the pressure of their triple point is very high and it is difficult to obtain them as liquids.
  • There are other solids whose vapor pressure overtakes that of the liquid before melting can occur.

• Interpreting Phase Diagrams

  • Phase diagrams are divided into three single phase regions that cover the pressure-temperature space over which the matter being evaluated exists: liquid, gaseous, and solid states.
  • When evaluating the phase diagram, it is worth noting that the solid-liquid phase boundary in the phase diagram of most substances has a positive slope.
  • This is due to the solid phase having a higher density than the liquid, so that increasing the pressure increases the melting temperature.
  • However, the solid-liquid phase boundary for water is anomalous, in that it has a negative slope.
  • The dotted green line refers to the solid-liquid phase boundary for water.

• Homogeneous versus Heterogeneous Solution Equilibria

  • Reactions between solutes in liquid solutions belong to one type of homogeneous equilibria.
  • The phases may be any combination of solid, liquid, or gas phases, and solutions.
  • When dealing with these equilibria, remember that solids and pure liquids do not appear in equilibrium constant expressions.
  • The equilibrium constant K is simply [Br2], with the concentration of the pure liquid Br2 excluded.