Hitunglah fraksi mol urea di mana 30gr urea (Mr =60) yang dilarutkan dalam 500 gr H2O

x urea = n urea/n urea + n air

n urea = gr/mr = 30/60 = 1/3 = 0,33
n air = gr/mr = 500/18 = 27,77

x urea = 0,33/0,33+27,77
x urea = 0,33/28
x urea = 0,011