a sample of baking soda is heated and releases carbon dioxide gas into a 1000 ml flask. If the flask initially contains 753 ml of water and 305 mL remains after the gas has displaced a portion of the water, what is the volume of the gas?

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. 

Dsolubility let me know if you have any other questions for chemistry