Concept:Calculating an empirical formula requires a rigid step-by-step analytical process, beginning with identifying how much of the compound is made of each element by mass.
Formula:$$ \text{Step 1: } \% \text{ Composition} \rightarrow \text{Step 2: Moles} \rightarrow \text{Step 3: Ratio} $$
Solution:- Step 1: Determine the percentage composition by mass of each constituent element (often via combustion analysis).
- Step 2: Convert those percentages into moles (gram atoms) by dividing by the respective atomic masses.
- Step 3: Determine the atomic ratio by dividing all mole values by the smallest mole value found.
- Step 4: If the ratio contains fractions, multiply by a whole number to achieve integer subscripts.
Why other options are incorrect:- Options A, C, and D: These are the second, third, and fourth steps respectively. You cannot find gram atoms (moles) without first knowing the mass percentage (Step 1).
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.