Which of the following are TRUE? Choose ALL answers that apply. For a pure speci

Question

Which of the following are TRUE? Choose ALL answers that apply.

For a pure species, coexisting liquid and vapour phases at equilibrium have the same T and P, but different fugacities in each phase. For ideal solutions, the excess properties are zero. The activity coefficient of a species i is the ratio of its fugacity in a real solution to its fugacity in an ideal solution (at the same T, P and composition). For an ideal gas mixture. Gibbs theorem can be expressed mathematically as M^-ig i, (T, P) = M^ig (T, p_i), where M^ig_i is not equal to V^-ig_i. The Margules equations always accurately describe activity coefficients as a function of liquid composition. The excess Gibbs energy for a solution is zero if the solution is ideal. The fugacity coefficient is 1 for ideal gases, i.e, f_i = P. The fugacity of species i in solution, f^_i, is defined in relation to the chemical potential of pure species mu_i, as follows: mu_i = gamma_i(T) + RT gamma n f^_i The Lewsi/Randall rule applies to each species i in an ideal solution, and is given by: f^id_i = X_if_i The fugacity of pure species i, f_i, is defined in relation to the Gibbs free energy of pure species as follows: G_i = gamma_i(T) + RT Ln f_i

Explanation / Answer

A For a pure species, coexisting liquid and vapour phases at equilibrium have the same T and P, but different fugacities in each phase. ----FALSE

B. For ideal solutions, the excess properties are zero. . ----TRUE

C. The activity coefficient of a species i is the ratio of its fugacity in a real solution to its fugacity in an ideal solution (at the same T, P and composition). ----TRUE

D. For an ideal gas mixture, Gibbs theorem can be expressed mathematically as

Weg P) = Vgi(T, po, where T4i9i is not equal to VP. -FALSE

E. The Margules equations always accurately describe activity coefficients as a function of liquid composition.

F. The excess Gibbs energy for a solution is zero if the solution is ideal.-------FALSE

G. The fugacity coefficient is 1 for ideal gases, ie, fj = P. -TRUE

H. The fugacity of species i in solution, fa. is defined in relation to the chemical potential of pure species , as follows:

p = r1(T) + RT Ln fi --TRUE

J. The fugacity of pure species i, fi, is defined in relation to the Gibbs free energy of pure species as follows:

= 11(T) + RT Ln fi --------------FALSE

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In concoction thermodynamics, the fugacity of a genuine gas is a powerful halfway weight which replaces the mechanical incomplete weight in a precise calculation of the substance harmony consistent. It is equivalent to the weight of a perfect gas which has an indistinguishable concoction potential from the genuine gas. For instance, nitrogen gas (N2) at 0 °C and a weight of P = 100 atm has a fugacity of f = 97.03 atm.[1] This implies the substance capability of genuine nitrogen at a weight of 100 atm is not exactly if nitrogen were a perfect gas; the estimation of the compound potential is what nitrogen as a perfect gas would have at a weight of 97.03 atm.

Fugacities are resolved tentatively or evaluated from different models, for example, a Van der Waals gas that are nearer to reality than a perfect gas. The perfect gas weight and fugacity are connected through the dimensionless fugacity coefficient .[2]

{displaystyle arphi ={rac {f}{P}},} {displaystyle arphi ={rac {f}{P}},}

For nitrogen at 100 atm, the fugacity coefficient is 97.03 atm/100 atm = 0.9703. For a perfect gas, fugacity and weight are equivalent so is 1.

The commitment of nonideality to the substance capability of a genuine gas is equivalent to RT ln . Again for nitrogen at 100 atm, the substance potential is = id + RT ln 0.9703, which is not exactly the perfect esteem id in light of intermolecular alluring powers.

The fugacity is firmly identified with the thermodynamic movement. For a gas, the movement is just the fugacity separated by a reference weight to give a dimensionless amount. This reference weight is known as the standard state and typically picked as 1 environment or 1 bar, Again utilizing nitrogen at 100 atm for instance, since the fugacity is 97.03 atm, the movement is only 97.03 without units.

Exact estimations of synthetic harmony for genuine gasses ought to utilize the fugacity instead of the weight. The thermodynamic condition for substance harmony is that the aggregate compound capability of reactants is equivalent to that of items. On the off chance that the compound capability of every gas is communicated as an element of fugacity, the balance condition might be changed into the commonplace response remainder frame (or law of mass activity) aside from that the weights are supplanted by fugacities.

For a dense stage (fluid or strong) in balance with its vapor stage, the compound potential is equivalent to that of the vapor, and accordingly the fugacity is equivalent to the fugacity of the vapor. This fugacity is around equivalent to the vapor weight when the vapor weight is not very high.

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