5 points Elon Musk is trying to figure out how much oxygen he needs to get to
Mars. He has already used the standard heats of formation to calculate
how much heat energy the combustion of kerosene will produce. He then
figured out how many moles of kerosene he needs to produce the amount
of heat energy required to get to Mars. How can he figure out how many
grams or liters of oxygen he needs? Use the following terms: LAW OF
CONSERVATION OF MASS, BALANCED CHEMICAL REACTION.
STOICHIOMETRY, MOLE-TO-MOLE RATIO

Yes it would be a physical change.

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.