Question

Calculate the number of molecules in 3.65g of HCL gas.

Answer 1

no. of moles = mass/ Molar mass

no. of moles (n) = 3.65/35.5+1

n = 3.65/36.5

n = 0.1

no. of moles = no. of molecules/ Avagadro No

0.1 = N/6.022×10^23

N = 0.1 × 6.022×10^23

N = 6.022× 10^22

Answer 2

Given:

3.65 grams of HCl gas.

To find:

The number of molecules.

Solution:

To determine the number of molecules m we have to use the below formula as follows-

The atomic mass of the H atom is 1 gram and the atomic mass of the Cl atom is 35.5 grams.

Hence the molecular mass of HCl is 35.5+1=36.5 grams.

We know that-

36.5 grams of HCl has $6.022×10^{23}$ number of molecules.

So, 3.65 grams of HCl has $6.022×10^{23}×3.65/36.5=6.022×10^{22}$ number of molecules.

So, 3.65 grams of HCl has $6.022×10^{22}$ number of molecules.