Suppose you have a solution that might contain or all of the following cations: cu2+, ag+, ba2+, and mn2+. addition of hbr causes a precipitate to form. after the precipitate is filtered off, h2so4 is added to the supernate another precipitate forms. this precipitate is filtered off, and a solution of naoh is added to the supernatant liquid until it is strongly alkaline. no precipitate is formed. which ions are present in each of the precipitates? which cations are not present in the original solution?

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.