There are 4 moles of nitrogen in 1 mole of caffeine.
The molar mass of nitrogen is 14 g/mol.
[tex]\begin{aligned} \text{mass of N} & = \text{0.10 mol caffeine} \times \frac{\text{4 mol N}}{\text{1 mol caffeine}} \times \frac{\text{14 g N}}{\text{1 mol N}} \\ & = \boxed{\text{5.6 g}} \end{aligned}[/tex]
Hence, there are 5.6 g of nitrogen in 0.10-mol sample of caffeine.
[tex]\\[/tex]
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