What is the freezing point of radiator fluid that is 50% antifreeze by mass? for water is 1.86 . I used delta: K_fc_m First I found the molar mass of ethylene glycol to be 62.07 g/mol. Then I multiplied 1/62.06 by 500g/1 kg to get 8.06 mol/kg for cm. I plugged these values in and got 15 C. However it is incorrect. I then thought to say that -15C was the freezing point, this was also wrong. Please help!