To calculate the standard enthalpy change for the fusion of 10 grams of solid sodium, we first need to determine the number of moles of sodium in 10 grams. The molar mass of sodium Na is 22.99 g/mol.Number of moles = mass / molar massNumber of moles = 10 g / 22.99 g/mol 0.435 molNow, we can use the molar heat of fusion 2.60 kJ/mol to calculate the standard enthalpy change for the fusion of 0.435 mol of sodium.Standard enthalpy change = number of moles molar heat of fusionStandard enthalpy change = 0.435 mol 2.60 kJ/mol 1.13 kJTherefore, the standard enthalpy change for the fusion of 10 grams of solid sodium at its melting point is approximately 1.13 kJ.