What would be the volume in liters of an ideal gas, if a 0.425 mole sample of the gas had a temperature of 900 degrees celsius at a pressure of 3.00 atmospheres? (the ideal gas constant is 0.0821 l•atm/mol•

The ideal gas law relates the pressure (P), volume (V), number of moles (n), and temperature (T) of a given ideal gas through the equation,

                                 PV = nRT 

If we are to determine the volume of the gas, we derive the equation such that it takes the form of,
                                 V = nRT/P

Substituting,
             V = (0.425 mol)(0.0821 L.atm/mol.K)(900 + 273 K) / 3 atm

                            V = 13.64 L

Thus, the volume of the ideal gas is approximately 13.64 L. 

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.