Question

A. 12 CO₂(g) + 6H₂O(g) -> 2C₆H₆(g) + 15O₂(g)

is change is S negative or positive? why?

B. [Zn(OH)₄]^2-(aq) -> Zn²⁺(aq) + 4 OH^-(aq)

is change is S negative or positive? why?

C. CH₃OH_(l) converted to CH₃OH(s)

is change is S negative or positive? why?

D. Cd²⁺(aq) + 2Cl^-(aq) -> CdCl₂(s)

is change is S negative or positive? why?

Answer 1

entropy of gas > entropy of aqueous > entropy of liquid > entropy of solid

A. 12 CO2(g) + 6H2O(g) -> 2C6H6(g) + 15O2(g)

reactant has more gases (18 moles) as compared to products (17 moles)

So, S is more for reactant

Hence, change in S is negative

B. [Zn(OH)4]2-(aq) -> Zn2+(aq) + 4 OH-(aq)

product has more aqueous components

So, S is more for product

Hence, change in S is positive

C. CH3OH(l) converted to CH3OH(s)

liquid is changing to solid

So, entropy is decreasing

Hence, change in S is negative

D. Cd2+(aq) + 2Cl-(aq) -> CdCl2(s)

There is aqueous in reactant and solid in product

So, entropy is decreasing

Hence, change in S is negative