To calculate the amount of heat released when 10.0 g of methane is burned completely, we need to use the enthalpy of combustion and the molar mass of methane.First, let's find the moles of methane:Molar mass of methane CH4 = 12.01 g/mol C + 4 * 1.01 g/mol H = 12.01 + 4.04 = 16.05 g/molNow, we can find the moles of methane:moles = mass / molar massmoles = 10.0 g / 16.05 g/mol = 0.623 molNow, we can use the enthalpy of combustion to find the heat released:Heat released = moles * enthalpy of combustionHeat released = 0.623 mol * -890 kJ/mol = -554.47 kJThe negative sign indicates that the heat is released exothermic reaction .So, the amount of heat released when 10.0 g of methane is burned completely in excess oxygen is 554.47 kJ.