How come there is only 3 c5h12 isomers?

T(s) in2os] (m) 0 185 2.39 546 1.90 725 1.70 the decomposition of n205 can be described by the equation 2.68 given these data for the reaction at 45°c in carbon tetrachloride solution, calculate the average rate of reaction for each successive time interval. ntr s to 185 s 185 s to 546 s 546 s to 725 s number number number reaction rate: m/s m/s m/s