Question

How many molecules are in 13.5 g of sulfur dioxide?

Answer 1

Oxygen-8×2=16, sulphur=16
1mole=6.023×10^23molecule=22.4l=32gram

32g=6.023×10^23molecule
1g=6.023×10^23÷32
13.5g=6.023×10^23÷32×13.5
=2.5×10^23 molecule
.°. there are 2.5×10^23 molecule in 13.5g of sulphur dioxide

Answer 2

Answer: There will be  $1.27*10^2^3molecules$ of sulfur dioxide.

Explanation: Sulfur dioxide is $SO_2$ with one sulfur and two oxygen atoms. The question asks to calculate the number of molecules in 13.5 grams of it.

It's a two step conversion. In first step, grams are converted to moles and in second step the moles are converted to the molecules.

To convert grams into moles, the grams are divided by the molar mass of the compound and then multiplied by the Avogadro number to convert the moles to molecules.

Molar mass is the sum of atomic masses. Atomic mass of O is 16 and that of S is 32.

Molar mass of sulfur dioxide = 2(16)+32 = 64 gram per mol

The set up for both the steps could be shown using dimensional analysis.

$13.5gSO_2(\frac{1molSO_2}{64gSO_2})(\frac{6.022*10^2^3molecules}{1mol})$

= $1.27*10^2^3molecules$