Question

How many moles of silver atoms are there in 1. 8 x 1020 atoms of silver?.

Answer 1

Answer:

Taking into account the definition of avogadro's number, 1.8×10²⁰ atoms of silver are in 2.98×10⁻⁴ moles of silver.

First, you have to know that it is called Avogadro's Number or Avogadro's Constant. By Avogadro's number it is understood the number of elementary entities (that is, of atoms, electrons, ions, molecules) that exist in a mole of any substance. Its value is 6.023×10²³ particles per mole.

Avogadro's number represents a quantity without an associated physical dimension, so it is considered a pure number that allows describing a physical characteristic without an explicit dimension or unit of expression.

Avogadro's number applies to any substance.

Then you can apply the following rule of three: if 6.023×10²³ atoms are contained in 1 mole of silver, then 1.8×10²⁰ atoms are contained in how many moles of silver?

amount of moles of silver= (1.8×10²⁰ atoms × 1 mole)÷ 6.023×10²³ atoms

amount of moles of silver= 2.98×10⁻⁴ moles

Finally, 1.8×10²⁰ atoms of silver are in 2.98×10⁻⁴ moles of silver.

Answer 2

Answer:

3.0 × 10^-4 mol

Explanation:

Avogadro's constant = 6.02 × 10^23

let's make the unknown number of moles = x

1 mole = 6.02 × 10^23 atoms

x = 1.8 × 10^20 atoms

cross multiply

6.02 × 10^23 atoms x = 1.8 × 10^20 atoms

divide both sides by 6.02 × 10^23 atoms

x = (1.8 × 10^20 atoms) ÷ (6.02 × 10^23 atoms) = 3.0 × 10^-4

number of moles = 3.0 × 10^-4