1) Answer is: there are 9.04 moles of the hydrogen in 4.52 mol of the water.
n(H₂O) = 4.52 mol; amount of the water molecules.
In one molecule of the water, there are two hydrogen atoms.
n(H₂O) : n(H) = 1 : 2.
n(H) = 2 · n(H₂O).
n(H) = 2 · 4.52 mol.
n(H) = 9.04 mol; amount of the hydrogen atoms.
2) Answer is: there are 25.29 moles of the hydrogen in 8.43 mol of the ammonia (NH₃).
n(NH₃) = 8.43 mol; amount of the ammonia molecules.
In one molecule of the ammonia, there are three hydrogen atoms.
n(NH₃) : n(H) = 1 : 3.
n(H) = 3 · n(NH₃).
n(H) = 3 · 8.43 mol.
n(H) = 25.29 mol; amount of the hydrogen atoms.
3) Answer is: there are 0.408 moles of the hydrogen in 0.102 mol of the hydrazine (N₂H₄).
n(N₂H₄) = 0.102 mol; amount of the hydrazine molecules.
In one molecule of the hydrazine, there are four hydrogen atoms.
n(N₂H₄) : n(H) = 1 : 4.
n(H) = 4 · n(N₂H₄).
n(H) = 4 · 0.102 mol.
n(H) = 0.408 mol; amount of the hydrogen atoms.
4) Answer is: there are 770 moles of the hydrogen in 35.0 moles of the decane (C₁₀H₂₂).
n(C₁₀H₂₂) = 35.0 mol; amount of the decane molecules.
In one molecule of the decane, there are twenty two hydrogen atoms.
n(C₁₀H₂₂) : n(H) = 1 : 22.
n(H) = 22 · n(C₁₀H₂₂).
n(H) = 22 · 35.0 mol.
n(H) = 770 mol; amount of the hydrogen atoms.
