What are the contributions of these elements in industries and in the environment?

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

How can a give a full method for the experiment of separating sand from water by filtration? 1-materials 2-steps 3-conclusion also for water and salt separated by the evaporation or distillation process