Calculate the mass of urea (`NH_2CONH_2`) required in making 5.5kg of 0.25 molal aqueous solution.

Answer

20

Explanation

(a)Yes. Any sized rings can be fused cis. (b)Yes, Spirances are known for any size ring if they are able to be at right angles. ( C)No, A three and a six membered ring cannot be fused trans. The trans bonds on the Potential bridgehead C's are too far apart to be bridged by a single carbon bridge.(d)No. As in ( c) a four and a five membered ring cannot be fused trans. (e)Yes. Two five membered (and larger ) rings can be fused trans because the trans bonds on the bridgehead C's are in position for a 3-C budge. (f) Yes. Large rings can be trans- fused