# Solubility of urea in water

I'm hoping that this isn't too obvious of a question (it's been awhile since I've taken chemistry), but I was looking at the solubility table on Wikipedia, which gives the solubility as grams per 100 mL. My understanding is that 100 mL of water weighs 100 grams.

So here's what I was having trouble wrapping my head around: it lists the solubility as 108 (at least at 20 °C). If I understand that right, that would mean that I can absorb 108 grams of urea in 108 grams of urea in only 100 grams of water, right? Can someone explain why it's possible to have more urea than water in this case?

• Why would it be a problem to have more of urea than of water by mass? – Jan Jan 25 '17 at 21:25
• @Jan It just seems really weird to me that that would be the case, I'm trying to wrap my mind around why that's possible. – EJoshuaS - Reinstate Monica Jan 25 '17 at 21:35

$\dfrac{108}{60} = 1.8$ moles urea
$\dfrac{100}{18} = 5.6$ moles water
$\dfrac{5.6}{1.8} = 3.1$ molecules of water for every molecule of urea