Question

How many moles of argon (Ar) are present in 100.0 g of argon?

Answer 1

1mole =molecular weight
1mole of argon= 18g
100g=5.5moles

Answer 2

Answer: 2.5 moles of Argon is present.

Explanation: Argon is a noble gas having atomic number 18.

Number of moles is calculated by using the formula:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Molar mass of Argon = 40 g/mol

Given mass of Argon = 100 g

Putting the values in above equation, we get

$\text{Number of moles}=\frac{100g}{40g/mol}=2.5moles$