Naphthalene is a soft covalent solid that is often used in mothballs. Its molar mass is 128.18 g/mol and it contains 93.75% carbon and 6.25% hydrogen. Determine the molecular formula of napthalene from this data.

C10H8

Explanation:

To answer this question, we need to know the atomic masses of carbon and hydrogen. The atomic mass of carbon is 12 amu while that of hydrogen is 1 amu. We start answering the question by dividing the percentages of these elements by their atomic masses.

H = 6.25/1 = 6.25

C = 93.75/12 = 7.8125

We proceed to divide both by the smallest number. This is 6.25

H = 6.25/6.25 = 1

C = 7.8125/6.25 = 1.25

The ratio of both is 1:1.25.

To make a whole number out of these, we multiply through by 4 and that gives 4:5

The empirical formula is thus C5H4

Now, we calculate the molecular formula:

(C5H4)n = 128.18

(5(12) + 4(1))n= 128.18

(60+4)n = 128.18

64n = 128.18

n = 128.18/64

n = approximately 2

The molecular formula is thus C10H8

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.

fe 55.85 g/mol and h2o 18.02 g/mol.