J.R. S. answered 05/11/22
Ph.D. University Professor with 10+ years Tutoring Experience
35.0 g x 1 mol / 16.08 g = 2.177 moles of substance (assuming molar mass is in g / mol)
q = m∆Hvap
q = heat = 6.411 kJ
m = mass = 2.177 moles
∆Hvap = enthalpy of vaporization = ?
Solving for ∆Hvap, we have ...
∆Hvap = q / m = 6.411 kJ / 2.177 moles
∆Hvap = 2.945 kJ / mol = 2.95 kJ / mol (3 sig. figs.)