You should not have any problems.
I'm currently running a
- i5 @ 3.0Ghz
- 8GB RAM
- Intel® HD Graphics 2000
I have little bit better CPU than yours and more RAM, I believe that the graphics card are about the same(I think that the HD 3000 is the laptop model and the HD 2000 is the desktop) but you may have a slightly better Graphics card.
While I do have more RAM I almost never use more than 1.5GB, most of the time I'
m only using 800-1000MB so you should have plenty of RAM.
I don't usually have 20 tabs open but I have 10 every so often and don't notice any less performance than when I only have one or two open.
Watching You Tube videos presents no problems for me even if a have more than one tab open while doing so, you should have no problem there either.
Up until this Feb. I was running Ubuntu on my old computer(2.5Ghz dual core Intel) that was about 6 years old and had no problems with that one either.
In short, I would have no worries recommending the laptop you bought even if you had asked before the purchase. I am very happy with my very similar system, enjoy yours.