This question is incomplete, the complete question is;
You want to plate a steel part having a surface area of 240 in² with a 0.002-in thick layer of silver.
The atomic mass of silver is 107.868 g/mol .
The density of silver is 10.49 g/cm³.
How many atoms of silver are required?
Answer:
4.6 × 10²³ atoms of silver are required
Explanation:
Given the data in the question;
first, we determine the volume of silver layer
volume of silver layer = surface area × thickness
we substitute
volume of silver layer = 240 in² × 0.002-in = 0.48 in³
we know that 1 in³ = 16.387 cm³
so, volume of silver layer = 0.48 × 16.387 = 7.87 cm³
Next we calculate mass of silver;
⇒ density × Volume
mass of silver = 10.49 g/cm³ × 7.87 cm³ = 82.5563 g
Now, number of atoms of silver are required will be;
Number of atoms = (mass/atomic mass) × Avogadro number
we know that A.v no. is 6.02214 × 10²³ mol⁻¹
so
Number of atoms = (82.5563 g / 107.868 g/mol . ) × 6.02214 × 10²³ mol⁻¹
= 0.7653 × 6.02214 × 10²³
= 4.6 × 10²³ atoms
Therefore; 4.6 × 10²³ atoms of silver are required
