How do I calculate standard entropy? Because I have no clue how and my teacher never explained it. Here's the question on my sheet though.

Calculate the standard entropy for the following reaction was this a favorable or unfavorable change?

2H(2) of H(2) + Cl(2) = 2HCl

S of H(2) = 130.6 JK MOL
S of Cl(2) = 233.0 JK MOL
S of HCl = 186.7 JK MOL

Please help me! I can't fail this class!

Question

How do I calculate standard entropy?  Because I have no clue how and my teacher never explained it. Here's the question on my sheet though.

Calculate the standard entropy for the following reaction was this a favorable or unfavorable change?

2H(2) of H(2) + Cl(2) = 2HCl

S of H(2) = 130.6 JK MOL
S of Cl(2) = 233.0 JK MOL
S of HCl = 186.7 JK MOL

Please help me! I can't fail this class!

matt101 · Answer

If you're given the entropy (S) for each individual reactant and product in the equation, the net entropy of the equation is the entropy of the products minus the entropy of the reactants. Just be sure to multiply each individual entropy value by the coefficient in the equation!

If your net entropy is positive, then entropy increases as a result of the reaction and so the reaction is favourable.

If your net entropy is negative, then entropy decreases as a result of the reaction and so the reaction is unfavourable.

Do the calculations and let me know what you get!

PS. I think S of Cl(2) is 223 J/K mol

anonymous · Answer

I asked a few other people and I finally got it. Thank you for your help!