Final answer:
To find the empirical formula for a 100-g sample with 87.42 g of nitrogen and 12.58 g of hydrogen, convert the masses to moles, calculate the simplest whole number ratio, and deduce that the empirical formula is NH₂.
Step-by-step explanation:
To find the empirical formula for a compound from a 100-g sample containing 87.42 g of nitrogen and 12.58 g of hydrogen, we need to convert the masses to moles. The relative atomic mass of nitrogen (N) is approximately 14 g/mol and hydrogen (H) is about 1 g/mol. First, we calculate the number of moles of nitrogen and hydrogen:
- Moles of N = 87.42 g / 14 g/mol = 6.2443 moles
- Moles of H = 12.58 g / 1 g/mol = 12.58 moles
Next, we find the simplest whole number ratio by dividing each number of moles by the smallest number of moles calculated:
- Ratio for N = 6.2443 / 6.2443 = 1
- Ratio for H = 12.58 / 6.2443 ≈ 2
The ratios suggest that there is one atom of nitrogen for every two atoms of hydrogen in the compound, resulting in an empirical formula of NH₂.