Answer:
Hi, this is a super vague question, so its pretty confusing to answer. Could you please be a bit more specific?
If you are referring to chemistry, then how you tell "what is what" is by the molecular makeup of an element (Periodic table), and "how that..affects what", chemical reactions can occur between elements
Answer:
Every mole contains 6.022 x 10^23 atoms regardless of what type of moelcules it is (Gold, Silver). So the anwer is 1.54 times 6.022 x 10^2
Weight is properly defined as how much gravity acts upon an object.
I hope this helps!