Calculate how much sample remains of a 200 g sample of Polonium-210 after 552 days (Polonium-210 has a half-life of 138 days).

Asubstance is held in an open container. its particles move past one another at random speeds but do not leave the container. heat is removed from the system, and the particles slow down. when enough heat is removed, the particles no longer have enough speed to overcome the weak attractive forces between them. when this happens, the substance enters its solid state. the process described above is known as .