I have had numerous problems with the CD burning software on Ubuntu. Only one option eventually satisfied me (but unfortunately it is not open source): Nero Linux 4.  Nero offers a free 30 trial before you have to buy. I don't know if Nero will solve the problem you are experiencing or not. But it being propietary might bypass whatever is causing the problem on Ubuntu?

What I would recommend is to try K3B on Ubuntu. You will have to install the KDE libraries to install K3B though. If K3B does not work for you, I would try Nero. Nero for Linux did everything I asked and had all the options I was looking for.

I'm hoping that the poor quality and dearth of features of the open source CD burning options will be addressed at some point for Ubuntu because I don't like having to use closed source stuff. But, unfortunately, I have not found a better alternative for CD burning on Ubuntu.

How do I burn a DVD with more than 3.8 GB data?
In Vogel's organic book, they have mentioned that in the Lund and Bjerrum method of purification of ethanol, magnesium is added, which forms ethanolate. But they said to activate the magnesium first by iodine. 

Why is the activation needed and how exactly does this activation process work in the activation of magnesium?
