How much energy (in kj) is required to ionize 2.78 moles of hydrogen atoms

Question

the right answer is: 3.65x10^3 kj
wondering how they got this answer.

Answer 1

E = 2.18E-18 J x (1/1 - 1/0) = 2.180E-18 J x (1 kJ/1000J) x 2.78 mol H atoms x 6.02E23 atoms/mol = ?