To calculate the enthalpy change, we first need to determine the number of moles of sodium hydroxide NaOH in 10 grams.The molar mass of NaOH is:Na = 22.99 g/molO = 16.00 g/molH = 1.01 g/molTotal = 22.99 + 16.00 + 1.01 = 40.00 g/molNow, we can find the number of moles of NaOH in 10 grams:moles = mass / molar massmoles = 10 g / 40.00 g/mol = 0.25 molNow that we have the number of moles, we can calculate the enthalpy change using the molar enthalpy of solution:enthalpy change = moles molar enthalpy of solutionenthalpy change = 0.25 mol -44.5 kJ/mol = -11.125 kJThe enthalpy change when 10 g of sodium hydroxide is dissolved in 100 mL of water is -11.125 kJ.