Question

How much heat is released when 6.00 g of methane is combusted using the reaction below? CH₄ + 2O₂ → CO₂ + 2H₂O ΔHrxn = -890 kJ

1) -8.54 x 10⁴ kJ
2) 334 kJ
3) -334 kJ
4) 8.54 x 10⁴ kJ

Answer 1

The combustion of 6.00 g of methane releases approximately 332.99 kJ of heat. This is calculated using stoichiometric principles and the molar mass of methane.

Step-by-step explanation:

To determine how much heat is released when 6.00 g of methane is combusted, we use the provided thermochemical equation and apply stoichiometric calculations:

CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) + 890.4 kJ

First, we need to convert the mass of methane to moles using its molar mass (16.04 g/mol):

Moles of CH4 = 6.00 g / 16.04 g/mol = 0.374 moles

Since the combustion of 1 mole of methane releases 890.4 kJ, the combustion of 0.374 moles will release:

Heat released = 0.374 moles × 890.4 kJ/mole = 332.99 kJ