To calculate the entropy change for the combustion of methane at constant pressure and standard conditions, we need to consider the balanced chemical equation for the combustion of methane:CH g + 2O g CO g + 2HO g Next, we need the standard molar entropy values S for each substance involved in the reaction at 298 K. These values can be found in standard thermodynamic tables. The values are:S CH = 186.3 J/molKS O = 205.2 J/molKS CO = 213.8 J/molKS HO = 188.8 J/molKNow, we can calculate the entropy change S for the reaction using the formula:S = S products - S reactants S = [1 S CO + 2 S HO ] - [1 S CH + 2 S O ]S = [1 213.8 + 2 188.8] - [1 186.3 + 2 205.2]S = [213.8 + 377.6] - [186.3 + 410.4]S = 591.4 - 596.7S = -5.3 J/molKThe entropy change for the combustion of methane at constant pressure and standard conditions is -5.3 J/molK.