RE: Questions about electric power and rc terminology
Unfortunately, you can't make that assumption. There are many RTF setups out there that are simply designed to get your money, not fly. Whether the companies do this intentionally, or they simply don't understand the basics of electrics is debateable, but the long and short of it is, "buyer beware."
Looking at the plane you bought, I think you'll be okay, but it may turn out to be a little underpowered. You might consider upgrading to an 8-cell battery pack, or adding a gearbox and going to a 10-cell pack. The additional Volts will give the plane a power boost, and the gearbox will allow the motor to spin a larger prop at a lower RPM, giving it a better, more efficient "bite" on the air.