To calculate the amount of heat released when 10.0 g of methane gas is burned in excess oxygen, 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 for carbon + 4 1.01 g/mol for hydrogen = 12.01 + 4.04 = 16.05 g/molNow, we can find the moles of methane in the 10.0 g sample:moles of CH4 = mass / molar mass = 10.0 g / 16.05 g/mol = 0.623 molesNow, we can use the enthalpy of combustion to find the amount of heat released:H = moles enthalpy of combustionH = 0.623 moles -890.3 kJ/mol = -554.7 kJThe amount of heat released when 10.0 g of methane gas is burned in excess oxygen is 554.7 kJ.