How many grams of iron are in 350 mg of iron?

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?

If e is the symbol for an element, which two of the following symbols represent isotopes of the same element? 1. e2. e3. ea.1 and 2c.1 and 4b.3 and 4d.2 and 3

What is the name of the enzyme that forms at the start of transcription?