Ubuntu has locked the root account. You can enable it, but the whole mentality is Ubuntu is designed on the "it just works" premise. Which means restricting the use of root to prevent accidental damage to the OS. If you want to adjust read/write permissions, which I don't advise other than temporarily, then use the "sudo" command before the command you wish to use.
BTW: When partitioning for linux, I always seperate the filesystem from user. I end up with 3 partitions. 1 /root, 1 /home and 1 SWAP. This way I can replace my OS with little effect on user accounts. it also enables me to add packages with little or no messing in the root adjust permissions. Some packages aren't compiled properly and wont work until you do adjust them (azureus comes to mind). Anyway, enough waffling.
Here's some usefull links for you:How to use CHOWN (CHange OWNer)Commands for changing user rightsHow to find the manpages (or Instruction guides for your bash commands)