Question

What is the value for ΔSºreaction for the following reaction, given the standard entropy values?
Al2O3(s) + 3H2(g) → 2Al(s) + 3H2O(g)

Answer 1

Substance Sº(J/mol*K)
Al2O3(s) 51
H2(g) 131
Al(s) 28
H2O(g) 189

(here is the table)

Answer 2

here are the answer choices,

–35 J/mol*K

+35 J/mol*/K

+179 J/mol*K

–179 J/mol*K

Answer 3

\[\Delta S = \Delta S _{products } - \Delta S _{reactants}\]

Answer 4

\[\Delta S _{products} = ( 2 * 28Jmol ^{-1}K ^{-1}) + (3 * 189Jmol ^{-1}K ^{-1})\]

Answer 5

The entropy given for each is for 1 mole right?
Since Al has 2 moles u multiply it by 2
Since H2O has 3 u multiply it by 3
Up to now do u get it ?

Answer 6

\[\Delta S _{reactants}= 51Jmol ^{-1}K ^{-1} + (3* 131Jmol ^{-1}K ^{-1})\]

Answer 7

Now substitute the values for the 1st equation !

Answer 8

I got +179

Answer 9

Did u get it ?