Question

Find the total number of moles
of HCL molecules in 3.65gram of HCL​

Answer 1

Mass of HCl = 3.65 grams

Atomic mass of H = 1 u

Atomic mass of Cl = 35.5 u

Molar mass of HCl = 1+ 35.5 = 36.5 u

Now , we have to find out total number of moles

of HCl molecules in 3.65gram of HCl.

We know that :-

$\rm \implies n = \dfrac{m}{w}$

Where :-

• n = number of moles
• m = given mass
• w = molar mass

Now put :-

• m = 3.65 grams
• w = 36.5 u

$\rm \implies n = \dfrac{3.65}{36.5}$

$\rm \implies n = \dfrac{365}{365} \times \dfrac{10}{100}$

$\rm \implies n = 1 \times \dfrac{1}{10}$

$\rm \implies n = 0.1 \: moles$

Answer :

Total number of moles of HCl molecules in 3.65gram of HCl = 0.1 moles

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Learn more :

$\rm \implies m=n \times w$

$\rm \implies n=\dfrac{a}{N_A}$

Where :-

• n = number of moles
• m = mass
• w = molar mass
• a = number of particles/atoms
• N_A = avogadro number