Question

Standard Entropy Hydrocarbons containing halogens are very useful molecules in synthetic chemistry. Calculate Sº for the reaction product in the equation shown below if Asº for the reaction is -130.0 J K-1. C2H4(9) + HCl(9) C2H5Cl(9) See appendices to your text for the needed thermodynamic data. Submit Answer Tries 0/5

Answer 1

Answer:-

Given:-

C₂H_4(g) + HCl_(g)$\rightarrow$ C₂H₅Cl_(g)

standard entropy change of the reaction ($\Delta$S⁰_rxn) = - 130.0 JK^-1

As we know that

standard entropy of HCl gas (S⁰_HCl) = 186.9 JK^-1

standard entropy of C₂H₄ gas (S⁰_C2H4) = 219.3 JK^-1

standard entropy of reaction product i.e C₂H₅Cl gas (S⁰_C2H5Cl) = ?

Also we know that

C₂H_4(g) + HCl_(g)$\rightarrow$ C₂H₅Cl_(g)

So according to the formula

standard entropy change of the reaction ($\Delta$S⁰_rxn) = S⁰_products -  S⁰_reactants  

standard entropy change of the reaction ($\Delta$S⁰_rxn) = (S⁰_C2H5Cl)   -  (S⁰_C2H4 + S⁰_HCl )

- 130.0 JK^-1 = (S⁰_C2H5Cl)   -  (219.3 JK^-1   + 186.9 JK^-1  )

- 130.0 JK^-1 = (S⁰_C2H5Cl)   -  (406.2 JK^-1  )

- 130.0 JK^-1 = (S⁰_C2H5Cl)   - 406.2 JK^-1

standard entropy of reaction product i.e C₂H₅Cl gas (S⁰_C2H5Cl) = - 130.0 JK^-1 + 406.2 JK^-1 ​​​​​​​

standard entropy of reaction product i.e C₂H₅Cl gas (S⁰_C2H5Cl) = 276.2 JK^-1 ​​​​​​​(i.e the answer)