Enthalpy and Entropy changes of two reactions are given below: Find out whether they are spontaneous or not at `27^oC`. Justify.
a) `DeltaH` = 26 kJ/mole, `DeltaS` = 8.3 J/K/mole
b)`DeltaH=-393.4` kJ/mole, `DeltaS` = 6 J/K/mole

Second law of thermodynamics deals with the spontanelty of a process. Iron is extracted from the ore Fe_2O_3 . Using the date given above suggest whether the decomposition of Fe_2O_3 is feasible or not. Substantiate. (DeltaH^@= 824 kJ//mol, DeltaS^@ + 0.276 kJ//mol K, T = 298 K).

Most of the naturally occuring processes are spontaneous. Find the temperature above which the reaction, MgO(s) + C(s) rarr Mg(s) + CO(g) becomes spontaneous. (Given Delta_rH^@ = 490 kJ//mol and Delta_rS^@ = 198 J//molK )

The value of for one mole of an ideal gas is nearly equal : (a) 2 J / mol K (b) 8.3 J / mol K (c) 4.2 J / mol K (d) 2 cal / mol K

Most of the naturally occurring processes are spontaneous. a) Give the criteria for spontaneity of a process in terms of free energy change ( DeltaG ) b) Exothermic reactions associated with a decrease in entropy are sponaneous at lower temperatures. Justify on the basis of Gibbs equation. c) Find the temperature above which the reactin MgO_((s))+C_((s))rightarrow Mg_((s))+CO_((g)) becomes spontaneous. (Given ( Delta_rH^theta=490kJmol^-1 & Delta_rS^theta=198JK mol^-1 )

Enthalpy of vapourisation of liquid water is 41 kJ mol^(-1) at 373 K. The change of internal energy when 1mole water at 373 K is converted to steam at 373 K is

The change of ice to water at 273 K in a thermodynamics reversible maner is represented below. ice harr water (i) , DeltaH = 6.61 kJ//mol, reversible Predict the entropy change of the surrounding from the above answer.

a) For the oxidation of iron 4 Fe_((s))+3O_(2(g))rightarrow2Fe_2O_(3(s)) , entropy change is -549.4 JK^-1mol^-1 at 298 K. Inspite of the negative entropy change of this reaction, why is the reaction spontaneous? ( DeltaH_r^0 for the reaction is - 1648xx10^3Jmol^-1 ). b) Write the difference between extensive and intensive properties. Give one example of each.