Determine whether the following descriptions of a car would be qualitative or quantitative observations.

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.

Achange in the number of neutrons in an atom will change an blank . when the number of protons changes in an atom, a new element will form.

Which fact represents evidence for the big bang theory?