To calculate the change in enthalpy H for the combustion of 10 grams of methane CH4 , we need to know the standard enthalpy of combustion for methane. The standard enthalpy of combustion for methane is -890.4 kJ/mol.First, we need to convert the mass of methane 10 grams to moles. The molar mass of methane is 12.01 g/mol C + 4 * 1.01 g/mol H = 16.05 g/mol.Now, we can find the moles of methane:10 g CH4 * 1 mol CH4 / 16.05 g CH4 = 0.623 mol CH4Next, we can calculate the change in enthalpy H for the combustion of 0.623 mol of methane:H = moles of CH4 * standard enthalpy of combustionH = 0.623 mol CH4 * -890.4 kJ/mol H = -555.1 kJTherefore, the change in enthalpy H for the combustion of 10 grams of methane CH4 at standard conditions is -555.1 kJ.