Question

How much heat is required to vaporize it? (assume a density of 1.00 g/ml.) express the heat in kilojoules to three significant figures?

Answer 1

Missing text find on internet: a 90,0 mL sample of water is heated to its boiling point.
V(H₂O) = 90,0 mL.
d(H₂O) = 1,00 g/mL.
m(H₂O) = 90 mL · 1,00 g/mL.
m(H₂O) = 90 g.
n(H₂O) = m(H₂O) ÷ M(H₂O).
n(H₂O) = 90 g ÷ 18 g/mol.
n(H₂O) = 5 mol.
Q = n(H₂O) · ΔHvap
Q = 5 mol · 40.65 kJ/mol.
Q = 203,250 kJ.
Q - heat reqiured.