One mole of U238 ( 6.022 X 10^23 atoms) is 238 grams; one mole of U235 is 235 grams. The difference in molecular weight between a mole of U235 and U238 is 3 grams, the secret to enriching uranium.
I looked on a solubility chart to answer this question, and hydroxides are generally insoluble (with some exceptions of course). However, it says to consider as an insoluble substance, though it may be moderately soluble.
The answer that you are most likely looking for is: Yes, a precipitate does form - this is due to the double placement reaction: