Final answer:
In 126 grams of nitric acid (HNO3), there are 1.2044x10^24 hydrogen atoms, calculated by first determining the number of moles of nitric acid and then using Avogadro's number to find the number of hydrogen atoms.
Step-by-step explanation:
To determine how many atoms of hydrogen are present in 126 grams of nitric acid (HNO3), we first need to find the number of moles of nitric acid in that mass.
The molar mass of nitric acid is approximately 1 (H) + 14 (N) + 3×16 (O) = 63 grams per mole. Now, we divide the given mass of nitric acid by its molar mass to find the number of moles:
126 g ÷ 63 g/mol = 2 moles of HNO3
Since each molecule of HNO3 contains one hydrogen atom, the number of moles of hydrogen atoms will be the same as the number of moles of HNO3. Therefore, by using Avogadro's number (6.022×1023 atoms/mole), we get:
2 moles × 6.022×1023 atoms/mole = 1.2044×1024 hydrogen atoms
Thus, there are 1.2044×1024 hydrogen atoms in 126g of nitric acid.