Answer:c
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12gHe/1 × 1molHe/4.0026g × 6.02x10^23atomHe/1mol = 1.8 atoms
Answer:
Nitrogen will called as atom or molecule or ion too in the state which it exist means in which form it is present .
An ion is partials and an atom is a base
The following is produced when propane (C₃H₈) is combusted completely : H₂O
<h3>Further explanation </h3>
Complete combustion of Hydrocarbons with Oxygen will be obtained by CO₂ and H₂O compounds.
If O₂ is insufficient there will be incomplete combustion produced by CO and H and O
Hydrocarbon combustion reactions (especially alkanes) 
For combustion of propane C₃H₈ (n = 3) ⇒ completely(excess O₂) :
C₃H₈+5O₂⇒3CO₂+4H₂O
The products of combustion : CO₂ and H₂O