Find the empirical formula of a compound which contains 54.93% potassium, 38.73% boron and 6.34% hydrogen.
a.
kbh
b.
kb2h4
c.
kb3h9
d.
k2b5h9

Hello!

Find the empirical formula of a compound which contains 54.93% potassium, 38.73% boron and 6.34% hydrogen.

A.     KBH

B.     KB2H4

C.     KB3H9

D.     K2B5H9

We have the following data:

Potassium (K) ≈ 39 a.m.u (g/mol)

Boron (B) ≈ 11 a.m.u (g/mol)

Hydrogen (H) ≈ 1 a.m.u (g/mol)

We use the amount in grams (mass ratio) based on the composition of the elements, see: (in 100g solution)

K: 54.93 % = 54.93 g

B: 38.73 % = 38.73 g

H: 6.34 % = 6.34 g

The values (in g) will be converted into quantity of substance (number of mols), dividing by molecular weight (g / mol) each of the values, we will see:

We realize that the values found above are not integers, so we divide these values by the smallest of them, so that the proportion does not change, let us see:

convert number of atomic radio into whole number

2 * (1 : 2.5 : 4.5)

= 2 : 5 : 9  ← whole number of atomic radio

K = 2

B =  5 

H = 9

Thus, the minimum or empirical formula found for the compound will be:

D.     K2B5H9

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