Place an empty 250 mL beaker on the balance and record its mass. Add your unknown rubber stopper to the beaker and record the mass again. Subtract these two values (with correct Sig. Fig.) to calculate the mass of the rubber stopper. (This technique is known as weighing by difference) b) Mass of an empty 250 mL Beaker (g) 155.625 g c) Mass of the 250 mL Beaker and Rubber Stopper (g) 180.825 g d) Mass of the unknown Rubber Stopper (g)

If this is a true or galse then its true but if not then what is the question?

1. why does the same side of the moon always face earthc.the rotational period of the moon is equal to one revolution around earth2. which is greater the moons period of rotation or its period of revolution  b.the moons revolution period around earth3.what was the major accomplishment of the apollo missions  c.sending the first human into space4. which of these space missions involved the deployment of lunar roversa. voyager 15. which scientists are going to explore next on kepler-186fd. evidence of existence of life6.which mission is not going to explore the outside of the solar  systemb.safir7.which technology limit the future of space explorationb. scientist must first develop certain technologies before missions can be completed.