Why do scientists need a system of measurements to measure physical quantities? a) scientists speak many different languages b) each country wants its own set of measurement standards c) measurements are seldom shared with scientists in different countries d) scientists want to share measurements data that everyone can understand

Plz choose one of the compounds from the table and explain how you know the numbers of atoms in your formula. is it possible for two different compounds to be made from the exact same two elements? why or why not? with a limited number of elements (less than 120 are known), does this mean we also have a small number of compounds or do we have a large number of compounds in this world?

How many atoms of mg are present in 97.22 grams of mg? 6.022 × 1023 2.408 × 1024 4.818 × 1024 5.855 × 1025

In 2002, the rare earth elements mine in mountain pass, california was closed because