Given values of ΔH and ΔS, select the reaction that is both spontaneous and endothermic. ΔH=−50…

➤ Why do I need to convert ΔS units before calculating ΔG?
You must use consistent energy units for ΔH and ΔS. ΔH is in kJ while ΔS is in J/K, so convert ΔS by dividing by 1000 to get kJ/K. Then compute TΔS in kJ. Matching units avoids arithmetic errors and yields a correct Gibbs free energy, ΔG = ΔH − TΔS.