6.1 A sample of compound V contains 54.56% C, 9.09% H, and 36.35% O.
6.1.1 Define the term empirical formula.
6.1.2 Use calculation to determine the empirical formula of compound V.
6.2 When 150 g hydrated aluminium chloride (AlCl3.nH2O) is dried, its mass decreases by 89.595 g.
6.2.1 Define water of crystallisation.
6.2.2 Determine the value of n in AlCl3.nH2O.
Answer (2)
The empirical formula of a compound represents the simplest whole-number ratio of atoms of each element present in the compound. It is the most basic representation of the chemical formula and can be determined experimentally.
Here's a more detailed explanation:
Simplest Ratio:
The empirical formula provides the smallest ratio of atoms. For example, in glucose (C6H12O6), the ratio of carbon, hydrogen, and oxygen is 6:12:6. The empirical formula, however, is CH2O, representing the simplified ratio of 1:2:1.
Experimental Determination:
Chemists can determine the empirical formula through experiments by measuring the mass or percentage composition of each element in a compound.
Molecular Formula vs. Empirical Formula:
While the empirical formula shows the simplest ratio, the molecular formula indicates the actual number of atoms in a molecule. For instance, the molecular formula for benzene is C6H6, while its empirical formula is CH.
Ionic Compounds:
All ionic compounds are represented by their empirical formulas because they exist as extended networks of ions rather than discrete molecules, according to Wikipedia. ;
The empirical formula of compound V is C2H4O, determined by calculating the simplest whole-number ratio of the elements. Water of crystallisation is the water chemically bonded to a crystalline compound, and n in AlCl3.nH2O is approximately 11, based on the mass loss upon drying. These calculations demonstrate an understanding of compound composition and hydration.
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