The Power of Chemical Calculations in Nitric Acid Production

How can we calculate the formula mass of nitric acid (HNO3) used in chemical reactions?

Ammonia is used to make nitric acid (HNO3). Calculate the formula mass (Mr) for nitric acid. (Show your working)

Formula Mass Calculation of Nitric Acid

The formula mass of nitric acid (HNO3) is calculated as (1*1) + (1*14) + (3*16) = 63 unified atomic mass units (u).

Explanation: The formula mass of a molecule is calculated by adding up the atomic masses of all the atoms it contains. In nitric acid (HNO3), there is one hydrogen atom (H), one nitrogen atom (N), and three oxygen atoms (O3). Using the periodic table, we find that the atomic masses for these are approximately 1, 14, and 16 respectively. Therefore, the formula mass for HNO3 = (1*1) + (1*14) + (3*16) = 63 u (unified atomic mass units). So, even though the content loaded Ammonia is used to make nitric acid (HNO3), it plays no role in calculating the formula mass of nitric acid.