How can you tell that this process is not at equilibrium? A) The reverse reaction is happening faster than the forward
reaction.
B) The forward reaction is happening faster than the reverse
reaction.
C) The reaction mixture is not complete as reactants are still
being added to the system.
D) The system is not at a constant temperature and must not be
at equilibrium.

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 answer is c) pyrite