The number of moles of CuO , that will be utilized in Dumas method for estimating nitrogen in a sample of 57…

Moles of $\mathrm{N}$N in $\mathrm{N}, \mathrm{N}$-dimethylaminopentane $=\frac{57.5}{115}=0.5$mol

${\mathrm{C}}_7{\mathrm{H}}_{17} \mathrm{N}+\frac{45}{2}\mathrm{CuO}⟶7{\mathrm{CO}}_2+\frac{17}{2}{\mathrm{H}}_2\mathrm{O}+\frac{1}{2}{ \mathrm{N}}_2+\frac{45}{2}\mathrm{Cu}$

$\frac{\text{ no. molesof CuO reacted }}{45/2}=\frac{\text{ no. molesof }{\mathrm{C}}_7{\mathrm{H}}_{17} \mathrm{N}\text{ reacted }}{1}$

$\therefore$ no. of moles of $\mathrm{CuO}$ reacted $=\frac{45}{2}\times 0.5=11.25=1125\times {10}^{-2}$