Hey there Tamara! So for each of these reactions we want to calculate their ΔS of reaction.
You will use this formula: ΔSrxn= sum of S of the products - sum of S of the reactants.
i) ΔS= [245.2 J/K mol] - [288.7 J/K mol] = -43.5 J/K
Do this for all the reactions. Note that in each reaction you have 1 mole of each reactant and product. If you had different number of moles for each, you would have to multiply the S values given by the number of moles of each, because those values are only per 1 mole.
Hope this helps! Let us know if you have any more questions.