2. is it possible for a balloon with an initial internal pressure equal to 250.0 kpa to naturally expand to four times its initial volume when the temperature remains constant and atmospheric pressure is 101.3 kpa? ,

No
Consider the formula: PV=nRT 
when one goes up, the other goes down because they are indirectly proportional

240+101.3=341.3kPa absolute pressure. 
341.3 * V = constant 
 expansion = Vfinal / Vinit = 341.3 / 240 

It is not enough.

To get a four times expansion, we need both a weakening of the balloon material and an ambient pressure that is lower than atmospheric at sea leve