Question

How many moles of argon are present if there are 1.23 x 10^20 atoms?

Answer 1

Answer:

2.04×10⁻⁴ moles of Ar

Explanation:

We begin from this knowledge:

1 mol of substance has 6.02×10²³ particles

Let's solve this by a rule of three:

6.02×10²³ atoms are contained in 1 mol of Ar

1.23×10²⁰ atoms must be contained in (1.23×10²⁰ . 1) / 6.02×10²³ =

2.04×10⁻⁴ moles of Ar