In: Chemistry
Entropy is a measure of disorder. So greater the number of degrees of freedom higher will be the entropy. So if a reaction proceeds in such a way the disorder/degrees of freedom increase then entropy will also increase.
a. Positive (KClO4, a solid decomposes to gas and KClO3. Number of particles increased from reactants to products and also O2 is a gas. So the entropy will be higher in products. Hence entropy change is positive).
b. Negative (Gas has more degrees of freedom/disorder than liquid. So entropy decreases and change is negative)
c. Positive (Even though the number of products is less than the number of reactants, one of the products (H2) is a gas which has more disorder. So effectively the disorder of prodcuts is high compared to that of reactants even though the number is less.)
d. Positive (Products has two gas atoms with very high degrees of freedom. So entropy change is positive)