Aballoon is filled with 3.00 l of helium at a pressure of 765 torr. what is the volume (l) of the balloon at an altitude where the pressure in the balloon is 70,661 pa?

We assume ideal gas behaviour so we can use the formula:

PV = nRT

From the problem, we can say that the amount of Helium does not change so n is constant and that we assume no change in temperature so that T is also constant, therefore:

P V = constant

And then:

P1 V1 = P2 V2

765 torr * 3.00 L =  70,661 Pa (760 torr / 101325 Pa) * V2

V2 = 4.33 L

mechanics (greek   is that area of science concerned with the behaviour of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment. the scientific discipline has its origins in ancient greece with the writings of aristotle and archimedes[1][2][3] (see history of classical mechanics and timeline of classical mechanics). during the early modern period, scientists such as galileo, kepler, and newton laid the foundation for what is now known as classical mechanics. it is a branch of classical physics that deals with particles that are either at rest or are moving with velocities significantly less than the speed of light. it can also be defined as a branch of science which deals with the motion of and forces on objects. the field is yet less widely understood in terms of quantum theory.

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