berapakah fraksi mol urea yang mengandung 12gr urea dalam 250 ml air

Fraksi Mol

Mr urea = 12 + 16 + 2 x 14 + 4 x 1
Mr urea = 60

Mr air = 2 x 1 + 16
Mr air = 18

n urea = m / Mr
n urea = 12 gram / 60
n urea = 0,2 mol

n air = m / Mr
n air = 250 ml / 18
n air = 13,888 mol

x urea = n urea / (n urea + n air)
x urea = 0,2 mol / (0,2 mol + 13,888 mol)
x urea = 0,2 mol / 14,088 mol
x urea = 0,014