To calculate the amount of heat released when burning 5.00 grams of methane CH4 in excess oxygen under standard conditions, we need to use the following equation:q = n H_combustionwhere q is the heat released, n is the number of moles of methane, and H_combustion is the enthalpy of combustion for methane.First, we need to find the number of moles of methane n . We can do this using the molar mass of methane:n = mass / molar massThe molar mass of methane CH4 is 12.01 g/mol for carbon + 4 1.01 g/mol for hydrogen = 16.04 g/mol.Now, we can find the number of moles of methane:n = 5.00 g / 16.04 g/mol = 0.3118 molNext, we need the enthalpy of combustion for methane H_combustion . The standard enthalpy of combustion for methane is -890.4 kJ/mol.Finally, we can calculate the amount of heat released q :q = 0.3118 mol -890.4 kJ/mol = -277.6 kJSo, the amount of heat released when burning 5.00 grams of methane in excess oxygen under standard conditions is approximately 277.6 kJ released, so negative sign indicates exothermic reaction .