Kethoxal, a substance used to combat viruses, is 48.6% carbon, 8.17% hydrogen, and 43.2% oxygen. it has a molar mass of 148 g / mol. what is the molecular formula of kethoxal?

Answer : The molecular formula of kethoxal is,

Solution :

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of C = 48.6 g

Mass of H = 8.17 g

Mass of O = 43.2 g

Molar mass of C = 12 g/mole

Molar mass of H = 1 g/mole

Molar mass of O = 16 g/mole

Step 1 : convert given masses into moles.

Moles of C =

Moles of H =

Moles of O =

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C =

For H =

For O =

The ratio of C : H : O = 1.5 : 3  : 1

To make a whole number we multiplying the ratio by 2, we get:

The ratio of C : H : O = 3 : 6  : 2

The mole ratio of the element is represented by subscripts in empirical formula.

The Empirical formula =

The empirical formula weight = 3(12) + 6(1) + 2(16) = 74 gram/eq

Now we have to calculate the molecular formula of the compound.

Formula used :

Molecular formula =

Therefore, the molecular of the kethoxal is,