mphilippe

Ah yes ok your explanation was clearing it !

thanks a lot!

Thanks Hermann, your answer helped a bit. According to the formula that is given on the wikipedia site, I get the carbon atom count right : 20.

I get the oxygen atom count right also : 5.

However I can't get the hydrogen count right. If each carbon has 4 bonds, so I would count that it has 4 hydrogen atoms attached. Right?

And to those that have an oxygen, I would count 2 hydrogen attached to the carbon, is that correct?

And what about the two bonds in the mollecule that are double bonds? How many hydrogen atoms would be there?

That way, I count 42 hydrogen and there is supposed to be 32. What do I do wrong?

Thanks a million for the help!

yes that's right but I would like to see how to count it from the stick figure

I was wondering if I could get any help in sorting out the mollecular formula of dinoprostone based on looking at its stick figure.

Thanks for the help!

http://en.wikipedia.org/wiki/Dinoprostone