Verified Answer :

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\(M_{C_{10}H_{14}N_{2}}=120+14+28=162\frac{g}{mol}\\\\ \%C=\frac{120*100\%}{162}\approx74,1\% \\\\ \%H=\frac{14*100\%}{162}\approx 8,7\% \\\\ \%N=100\%-74,1\%-8,7\%=17,2\%\)

Answer:

74.07% is the percent by mass of carbon in \(C_{10}H_{14}N_2\) .

Explanation:

Molar mass of compound\(C_{10}H_{14}N_2\) = M

\(M=10\times 12 g/mol+14\times 1g/mol+2\times 14 g/mol= 162g/mol\)

Number of carbon atom = 10

Atomic mass of carbon  = 12 g/mol

Percentage of element in compound :

\(=\frac{\text{Number of atoms}\times \text{Atomic mass}}{\text{molar mas of compound}}\times 100\)

Mass percentage of Carbon :

\(=\frac{10\times 12g/mol}{162 g/mol}\times 100=74.07\%\)

74.07% is the percent by mass of carbon in \(C_{10}H_{14}N_2\) .