Answer:
Scientists use the term magma for molten rock that is underground and lava for molten rock that breaks through the Earth's surface.
Hope this helps with the answer to your question
Answer:
What is the volume of the balloon when it rises in the atmosphere to a place where pressure is 640mmHg
I think you meant 
If you want to do that then you it will be 308
,
000
,
000
or if you meant 3 x 108 then it would literally just be 3 multiplied by 108 = 324