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entropy

In the special case of a substance isolated from external heat supply, dH=o, the change of entropy is zero in a reversible process, but must be positive if the process is not reversible.

Changes of entropy must be calculated in terms of quantities of heat, and must be interpreted in a similar manner.

Any change involving decrease of entropy is impossible.

If we write h=sot+dh, where so is a selected constant value of the specific heat of the liquid, and dh represents the difference of the actual value of h at t from the ideal value sot, and if we similarly write q5 = sologe(6/90)+dcp for the entropy of the liquid at t, where do represents the corresponding difference in the entropy (which is easily calculated from a table of values of h), it is shown by Callendar (Proc. R.S.

Writing formulae (3r) and (33) for the energy and entropy with indeterminate constants A and B, instead of taking them between limits, we obtain the following expressions for the thermodynamic functions in the case of the vapour: " =Solog e 0 - R log e p - ncp/D+A".

In practice, however, there is always some frictional dissipation, accompanied by an increase of entropy and by a fall of pressure.

The entropy tends to a maximum, and the state is one of stable equilibrium when the value of the entropy is the maximum value consistent with the conditions of the problem.

The adiabatics are lines of constant entropy, and are also called Isentropics.

In the case of an ideal gas, dp/d9 at constant volume =R/v, and dvld6 at constant pressure =R/p; thus we obtain the expressions for the change of entropy 0-4)0 from the state poeovo to the state pev, log e e/eo+R logev/vo =S log e 9/00-R (32) In the case of an imperfect gas or vapour, the above expressions are frequently employed, but a more accurate result may be obtained by employing equation (17) with the value of the specific heat, S, from (29), which gives the expression 4-¢o = Sologe0/00 - R logep/po-n(cp/B-copo/Bo)

The 0, 4) diagram is useful in the study of heat waste and condensation, but from other points of view the utility of the conception of entropy as a " factor of heat " is limited by the fact that it does not correspond to any directly measurable physical property, but is merely a mathematical function arising from the form of the definition of absolute temperature.

Since the condition of heat-isolation is impracticable, the condition of maximum entropy cannot, as a rule, be directly applied, and it is necessary to find a more convenient method of expression.

(29) (30) The expression for the change of entropy between any two states is found by dividing either of the expressions for dH in (8) by 0 and integrating between the given limits, since dH/B is a perfect differential.

If the change is not reversible, but the final state is the same, the change of entropy, do, is the same, but it is no longer equal to dII/B.

0, Entropy of vapour or liquid.

In virtue of relations (2), the change of entropy of a substance between any two states depends only on the initial and final states, and may be reckoned along any reversible path, not necessarily isothermal, by dividing each small increment of heat, dH, by the temperature, 0, at which it is acquired, and taking the sum or integral of the quotients, dH/o, so obtained.

The entropy cannot diminish.

Entropy.

In passing along an adiabatic there is no change of entropy, since no heat is absorbed.

(33) The state of a substance may be defined by means of the temperature and entropy as co-ordinates, instead of employing the pressure and volume as in the indicator diagram.

If 0', E', v'; and 4)", E", v", refer to unit mass of the substance in the first and second states respectively in equilibrium at a temperature 0 and pressure p, the heat absorbed, L, per unit mass in a change from the first to the second state is, by definition of the entropy, equal to 0(4)"-4)'), and this by the first law is equal to the change of intrinsic energy, E" - E', plus the external work done, p(v" - v'), i.e.

In all such cases there is necessarily, by Carnot's principle, a loss of efficiency or available energy, accompanied by an increase of entropy, which serves as a convenient measure or criterion of the loss.

In any small reversible change in which the substance absorbs heat, dH, from external sources, the increase of entropy, d0, must be equal to dH/9.

The total entropy of the system is found by multiplying the entropy per unit mass of the substance in each state by the mass existing in that state, and adding the products so obtained.

This quotient is called the change of entropy, and may be denoted by (4,"-0').

Even if the expansion is adiabatic, in the sense that it takes place inside a non-conducting enclosure and no heat is supplied from external sources, it will not be isentropic, since the heat supplied by internal friction must be included in reckoning the change of entropy.

In any spontaneous irreversible change, if the system is heat-isolated, there must be an increase of entropy.

0, Entropy.

acceptor splice site calculation program based on the maximum entropy model.

At higher energies, where there is no entropy bottleneck, this time scale separation disappears altogether.

Two voxel-based similarity measures, the linear correlation coefficient and the entropy correlation coefficient, are used.

Extension of the direct methods approach to structure solving by X-ray or electron crystallography based on the principle of maximum entropy.

In the microcanonical ensemble the presence of a first-order phase transition is indicated by two maxima in the Landau entropy separated by a well.

entropy ions are strongly hydrated, with small or negative entropies of hydration, creating local order and higher local density.

entropy of activation from these data.

entropy of the universe?

entropy of a black hole.

calculating entropy is easy enough with a calculator provided it has an ln button.

The activity of an organic process is the rate at which it increases the thermodynamic entropy of the universe.

The small boy who built the sandcastle reduced the entropy in a localized area by doing work.

Things tend to move toward disorder I think its called entropy or something that's Isaac's law.

D S itself can be separated into 2 components: Thermal entropy, Configurational entropy.

It is shown that thermal entropy can be given by: (3) where D S v is the molar thermal entropy.

If the braid formed by the rods has positive topological entropy, then material lines must grow exponentially, ensuring chaos.

I showed how gravitational entropy can be defined in general.

Combining probabilistic logic programming with the power of maximum entropy.

entropy bottleneck, this time scale separation disappears altogether.

entropy change for the total process?

entropy maximum.

entropy production and maximum efficiency?

entropy increase principle.

So they built Entropy on Dover Street (well, converted a former joiner 's building ).

Thus one can not localize the entropy on the horizon, which is just like the axis in ordinary three dimensional space.

molar thermal entropy.

They function on the principle of constrained maximization of the Shannon entropy, which produces the most statistically probable solution consistent with the constraints.

thermodynamic entropy of the universe.

Entropy restaurant serves top-notch, exciting, modern cuisine which entertains the eyes and tastebuds rather than simply fills the belly.

The majority of thermodynamical problems may be treated without any reference to entropy, but it affords a convenient method of expression in abstract thermodynamics, especially in the consideration of irreversible processes and in reference to the conditions of equilibrium of heterogeneous systems.

The rationale for the colligative properties is the increase in entropy on mixing solutes with the water.

entropy decreases.

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