Question

How many atoms of hydrogen are there in 2.57 *
10^-6 g of hydrogen?​

Answer 1

Answer:

First, you'll need to convert your mass of Hydrogen into the number of moles present in 10 g of Hydrogen. You can do this by dividing your mass of Hydrogen by its molar mass; most cases use 1 g/mol but some prefer more precision and may use 1.008 g/mol instead.

After finding the number of moles present, multiply the number of moles by Avogadro's number (denoted as NA, where the ‘A’ is in subscript), which converts the number of moles you have to the number of molecules/atoms of your substance of interest, which, in this case, is Hydrogen.

As an extension of your question, you should recall that Hydrogen is uncommonly found outside of its natural form of H2 (unless of course, you're in a lab that deals with lone Hydrogen atoms). If the answer you require is for the number of molecules instead of atoms, you'll need to divide the answer you previously obtained by two, since each molecule has two H atoms.

Answer 2

Hey mate here is your answer in the given picture :

Hope it helps.