Question

Caffeine is a bitter stimulant drug and is found in varying quantities in seeds, leaves, and so on. Its formula is C8H10N4O2. Match the number of moles of each element found in the specified number of moles of caffeine.

Answer 1

Let us assume that there is one mole of caffeine present. Elemental moles:
Carbon: 8 moles
Hydrogen: 10 moles
Nitrogen: 4 moles
Oxygen: 2 moles

Answer 2

Caffeine has chemical formula as C₈H₁₀N₄O₂. The molecule is made from 4 elements. They are C, H, N and O.

1 molecule of caffeine has 8 C, 10 H, 4 N and 2 O atoms.

                                   C₈H₁₀N₄O₂ → 8C + 10H + 4N + 2O

Stoichiometric ratio       1         :       8    : 10     :  4   :   2

Hence, 1 mole of C₈H₁₀N₄O₂ has 8 moles of C, 10 moles of H, 4 moles of N and 2 moles of O atoms.