Calculate the work, w, (in j) when 0.6 litre of an ideal gas at an initial pressure of 91.5 atm is expanded isothermally to a final pressure of 2.15 atm against a constant external pressure of 2.15 atm.
i got -130.71 j, but apparently it is wrong. is greatly appreciated.

To calculate work, in thermodynamics, the equation would be as follows:

W = - integral of PdV

P is a function of volume so we cannot really take the P out of the integral. INstead, we can use knowledge on ideal gas to relate P and V.

From the ideal gas equation,

P = nRT / V = k/V

91.5 = k / 0.6
k = 54.9

P = 54.9 / V

W = - integral of ( 54.9/V) dV

Integrating the expression from 91.5 to 2.15, we obtain

W = 205.92 Joules

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant.