how many atoms are there in 3.4 grams of ammonia
Ammonia is NH3
The molar mass (reading from the periodic table) is 17.031g/mol
Therefore 3.4 grams of ammonia is equal to 0.1996359579590159 moles of ammonia.
Multiplying this by 6.022 * 1023 we get 120220773882919374980000 molecules (or 1.2022 * 1023 molecules).
In 1 molecule of ammonia there are 4 atoms, so in total there are approx. 4.8088 * 1023 atoms.
The measurement was made using 2 significant figures, so we can only be sure about this result to 2 significant figures, therefore the amount of atoms in 3.4g of ammonia is approx. 4.8 * 1023 atoms.
Type in any other element instead of "ammonia" to get that too, in this case it's approxamitely 4.243*10^23 atoms.