What is the molecular formula of aluminum chloride, containing 20.2% by mass of aluminum and 79.8% by mass of chlorine? The relative molecular mass is 267 grams.A. Al2Cl4B. Al2Cl6C. Al2Cl2D. AlCl3



Answer :

Answer

Al₂Cl₆

Procedure

An empirical formula is a chemical formula showing the ratio of elements in a compound rather than the total number of atoms. It is the simplest whole number non-reducible ratio formula for a molecular formula or compound.

To find the empirical formula, we will need to follow the next steps:

0. Find the molar mass of each component (using the periodic table): Al=26.98, Cl=35.453

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1. Convert to moles: Al=0.7487, Cl=2.2509

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2. Find the smallest mole value: 0.7487

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3. Divide all components by the smallest value: Al=1, Cl=3.0065

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4. Round to closest whole numbers: Al=1, Cl=3

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5. Combine to get the empirical formula: AlCl₃

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6. Evaluate the weight of the current formula AlCl₃ = 133.34 g/mol

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7. Multiply by 2 to get the formula that matches the weight Al₂Cl₆ = 267 g/mol