Describe and explain the use of metals in dentistry and orthodontics

Does anyone know a lot about how to: - calculate mass of magnesium metal - calculate the actual yield of magnesium oxide - calculate the theoretical yield of mgo - calculate the percent yield of mgo - determine the percent yield of mgo - determine the average percent yield of mgo i had to do an online lab and its asking these questions but i have no idea where to start or how to be able to find these things. i can post the chart of the data from the lab or if you can tell me exactly how i can find each.

Which of the following shapes would represent a molecule with two bonded atoms and 3 lone pairs on only one of them , trigonal planar , bent , trigonal pyramidal , linear

The atoms of a solid aluminum can are close together, vibrating in a rigid structure. if the can is warmed up on a hot plate, what happens to the atoms?