Question

Sulfur dioxide gas reacts with hydrogen sulfide gas to produce elemental sulfur (S8) and water vapor. Predict the temperature range over which this reaction is spontaneous.

Answer 1

I would do this.
Write the equation and balance it. It's a little tricky but here it is.
8SO2 + 16H2S ==> 3S8 + 16H2O
Look up delta Hf in tables (probably in yur text or you can find them on the web) and determine delta Hrxn.
deltaHrxn = (n*products of reaction)-(n*reactants)
Do the same thing for delta Srxn the same way.
Then delta G = delta Hrxn -TdeltaSrxn.

Plug in the numbers for deltaHrxn and deltaSrxn and determine T which will give a negative number for delta G.