How much heat is released when 15.7g of methane (c2h6) is combusted if the enthalpy of the reaction is - 1560.7 kj

- 407.4 kJ of heat is released.

Explanation:

We have to write the balanced equation as,

2 C₂H₆(g) + 7O₂ → 4CO₂ + 6H₂O

Here 2 moles of ethane reacts in this reaction.

Now we have to find out the amount of ethane reacted using its given mass and molar mass as,

2 mol C₂H₆ × 30.07 g of C₂H₆ / 1 mol C₂H₆ = 60.14 g of C₂H₆

Heat released = ΔH × given mass / 60.14

                        = - 1560. 7 kj ×15.7 g / 60. 14 g  = -407. 4 kJ