Answer:
b) positive enthalpy change and negative entropy change.
c) - delta H.
Explanation:
The total energy or intrinsic energy(heat content) of a system is known as the enthalpy.
Entropy deals with the degree of randomness or disorderliness of a system.
The fraction of the total heat energy of system that does useful work is the Gibb's free energy(G).
The standard free energy change of system is expressed as:
ΔG° = ΔH° - TΔS°
ΔH° is the standard enthalpy change
ΔS° is the standard entropy change
T is the temperature
The sign of ΔG° can predict whether or not a change is spontaneous or not.
if ΔG° is negative, the change is spontaneous or feasible
ΔG° is positive then the change is non-spontaneous or non-feasible.
ΔG° is zero, the system is in equilibrium.
From free energy change equation, we see that if ΔH° is positive and ΔS° is negative, the value of the standard free energy change is positive and the reaction is non-spontaneous.
2 . c) - delta H i.e -ΔH
An exothermic change is a change in which heat is liberated to the surroundings. In this change, the surrounding is hotter at the end of the change. ΔH is assigned a negative sign as the sum of the heat contents of the products are less than that of the heat contents of the reactants.
