Answer:
Step-by-step explanation:
The change in entropy of a system can be determined by comparing the entropy of the reactants to the entropy of the products. The reaction that leads to an increase in the number of moles of gas or particles will generally have a positive change in entropy.
I. 2N2(g) + O2(g) → 2N2O(g)
The reactants have 3 moles of gas, while the product also has 3 moles of gas. Therefore, there is no change in the number of moles of gas, and the change in entropy is likely to be small.
II. CaCO3(s) → CaO(s) + CO2(g)
The reactant is a solid, while the products are a solid and a gas. The formation of a gas from a solid leads to an increase in the number of moles of particles, and therefore an increase in entropy.
III. Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
The reactants consist of a solid and a liquid, while the products consist of an aqueous solution and a gas. The formation of a gas leads to an increase in the number of moles of particles, and therefore an increase in entropy.
Therefore, reactions II and III have a positive change in entropyentropy