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Okay the serious stuff is comming
Empirical Formula mean The simplest whole number ratio of atoms of each element present in a compound. (WOW DOESN"T THAT SOUND COOL?)
Because the Pure awesomeness of Ionic compounds. They are given in Empirical formula already. (please don't go and ask the atoms why, they are just that awesome). The Covalent compounds are the strange ones they come in the right ratio but NOT SIMPLIFIED in math class that would be 1 mark off... so if a ionic compound went and did a math test with covalent the covalent would just barely pass while ionic gets perfect omg><.
Formula = n = molar mass of the compound/molar mass of the empirical formula
Okay now lets have some examples
A compound have 47.25% copper and 52.75% chlorine.
Find the empirical formula for this compound.
Cu 47.25g Atomic mass 63.6
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Cl 52.75g Atomic mass 35.5
52.75/35.5 = 1.49
Cu 0.74/0.74 = 1
Cl 1.49/0.74= 2.01 = 2
So the empirical formula for Cu Cl
is CuCl2
Ex 2~ what is the molar formula? molecular mass = 132.16 , empirical formula = C2H4O
n = 132.16/42 = 3.2
MM = 42g/mol
MF= 3(C2H4O) = C6H12O3
Ex3 empirical formula of a compound is CH and the molar mass is 104 g/mol, calculate the molecular formula.
mass of C = 12.0 g/mol
mass of H = 1.01 g/mol
empirical formula mass = 13.0 g/mol
CH = (104 g/mol)(1 mol/13.0 g) = 8.00
MF = 8(CH) or C8H8
Get chemistry notes from here What is empirical formula? Grade XII | Chemistry
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