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Ammonia is NH_{3}

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 * 10^{23} we get 120220773882919374980000 molecules (or 1.2022 * 10^{23 }molecules).

In 1 molecule of ammonia there are 4 atoms, so in total there are approx. 4.8088 * 10^{23 }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 * 10^{23} atoms.

Kreyn
Mar 24, 2017