A lab student analyzed a nickel-en complex for ethylenediamine, en, content. A 0.353g sample of the synthesized Ni-en complex was dissolved in about 50 mL of water and titrated with 0.165 M HCl (aq). Endpoint required 36.40 mL of the HCl (aq). What is the mass (in grams) of en in the Ni-en complex analyzed?