An industrial plant processes its waste water through a sedimentation tank that removes hazardous metals by precipitating them as insoluble carbonate salts. if sodium carbonate is gradually added to the tank, what would be the order of precipitation of the metals, pb2+, cu2+, hg22+, and zn2+ if each is ≈ 1.0 × 10–4 m? ( ksp pbco3 = 7.4 × 10–14, ksp cuco3 = 1.4 × 10–10, ksp hg2co3 = 8.9 × 10–17, and ksp znco3 = 1.4 × 10–11)

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. 

The correct answer is weight.

Aseasonal prevailing wind in the region of south and southeast asia, blowing from the southwest between may and september and bringing rain (the wet monsoon ), or from the northeast between october and april (the dry monsoon ).