PRESSURE AND TEMPERATURE RELATIONSHIP
held constant, there is a direct relationship between Pressure and Temperature . refrigerant releases latent heat by turning from a gas to a liquid as it cools. The density of a liquid will change with temperature and pressure. dV = V1 - V0 = change in volume - difference between final and initial volume (m3). Pressure and temperature (along with density or specific volume) are related by Equation of State. For gaseous fluids the ideal gas relation (p.V = R.T)is a good approximation. For incompressible fluids density is held constant with pressure while it varies inversely as the.
Boiling points of alkanesalkenesethershalogenoalkanesaldehydesketonesalcohols and carboxylic acids as a function of molar mass In general, compounds with ionic bonds have high normal boiling points, if they do not decompose before reaching such high temperatures. Many metals have high boiling points, but not all.
Boiling point - Wikipedia
Very generally—with other factors being equal—in compounds with covalently bonded moleculesas the size of the molecule or molecular mass increases, the normal boiling point increases. When the molecular size becomes that of a macromoleculepolymeror otherwise very large, the compound often decomposes at high temperature before the boiling point is reached.
Another factor that affects the normal boiling point of a compound is the polarity of its molecules. As the polarity of a compound's molecules increases, its normal boiling point increases, other factors being equal.
Water's Unexpected Properties
Closely related is the ability of a molecule to form hydrogen bonds in the liquid statewhich makes it harder for molecules to leave the liquid state and thus increases the normal boiling point of the compound.
Simple carboxylic acids dimerize by forming hydrogen bonds between molecules.Air pressure and temperature demo
A minor factor affecting boiling points is the shape of a molecule. Making the shape of a molecule more compact tends to lower the normal boiling point slightly compared to an equivalent molecule with more surface area.
Comparison of butane isomer boiling points Common name. The logarithm of the vapor pressure and the reciprocal temperature for liquid water ] Pressure-density relationship The density of liquid water tends towards an integral 6th power relationship with respect to pressure.
This relationship is shown below P' is the scaled pressure, that is, the left side of the above expression as the dashed lines, with the colored lines being the experimental data. The best fit is thus around the compressibility minimum at The extrapolated density at zero T and P is 1.
Densities of water tend towards a 6th power law dependent on temperature and pressure As this power law does not obey the rule of thumb that candidate power laws should exhibit an approximately linear relationship on a log-log plot over at least two orders of magnitude in both the x-axes and y-axes [ ], it seems likely that this relationship is purely empirical.
I am again grateful to Frank Grimer for pointing me at this relationship.
Volume change increases as the square-root 3 power of the temperature The square-root 3 term is related to the Vesica Piscesbeing the ratio of the long to short diameter of intersecting expanded icosahedral water clusters the short diameter being the distance between the centers of neighboring dodecahedra and the long diameter associated with a plane of water molecules between the two pentameric boxes Figure 3h joining them.
I am again grateful to Frank Grimer for showing me this relationship. Log10 T-T0 vs log viscosity data In the graph above, H2O values are shown by the green squares red lineand D2O values are indicated by the blue diamonds blue line. As this power law does not quite obey the rule of thumb that candidate power laws should exhibit an approximately linear relationship on a log-log plot over at least two orders of magnitude in both the x-axes and y-axes [ ], it seems possible that this relationship is curious but purely empirical.