Stoichiometry and equivalence ratio

Gas name	Fraction
Methane:
Acetylene:
Ethylene:					% Fuel:
Ethane:					Equivalence ratio:
Propylene:					% Air:
Propane:					% O2 :
Butane:
Hydrogen:

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For a specified fuel composition this calculator provides the stoichiometric composition of fuel with air (20.95 % oxygen). In addition, for a spcified fuel concentration with air, the equivalence ratio can be calculated - and vica versa.

The Stoichiometric composition is defined as the composition where the amounts of fuel and oxygen (air) are in balance so that there is no excess of fuel or oxygen after the chemical reaction has been completed.

In general:

C_nH_m + (n + 0.25m)(O₂ + 3.76 N₂) → n CO₂ + 0.5m H₂O + 3.76(n + 0.25m) N₂

References:
Bjerketvedt, D., Bakke, J.R. and Wingerden, K. van (1993) "Gas explosion handbook" Version1.2
Equivalence ratio in Wikipedia
Stoichiometry in Wikipedia