1 mole of Silicon atoms contains 6.02 x 1023 atoms. One mole of Silicon atoms
has a mass of 28.1 grams. How many atoms of Si are contained in a computer chip
that has a mass of 38.02 mg?
The Correct Answer and Explanation is :
To determine how many atoms of silicon (Si) are contained in a computer chip that has a mass of 38.02 mg, we first need to convert the mass from milligrams to grams, since the molar mass of silicon is given in grams per mole.
Step 1: Convert milligrams to grams
- Mass of the chip: 38.02 mg
- Conversion to grams:
[
\text{Mass in grams} = \frac{38.02 \, \text{mg}}{1000} = 0.03802 \, \text{g}
]
Step 2: Calculate the number of moles of silicon
The molar mass of silicon is given as 28.1 g/mol. We can use this information to calculate the number of moles in 0.03802 g of silicon using the formula:
[
\text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}
]
Substituting the values:
[
\text{Number of moles} = \frac{0.03802 \, \text{g}}{28.1 \, \text{g/mol}} \approx 0.001352 \, \text{mol}
]
Step 3: Calculate the number of atoms
To find the number of atoms, we can use Avogadro’s number, which states that 1 mole of any substance contains (6.02 \times 10^{23}) entities (atoms, molecules, etc.). Thus:
[
\text{Number of atoms} = \text{Number of moles} \times \text{Avogadro’s number}
]
Substituting the values:
[
\text{Number of atoms} = 0.001352 \, \text{mol} \times 6.02 \times 10^{23} \, \text{atoms/mol} \approx 8.13 \times 10^{20} \, \text{atoms}
]
Conclusion
A computer chip with a mass of 38.02 mg contains approximately (8.13 \times 10^{20}) silicon atoms. This calculation highlights the relationship between mass, moles, and the number of atoms, illustrating the importance of Avogadro’s number in quantifying atomic quantities from macroscopic measurements. In practical terms, this means that even a small mass of silicon, as found in a computer chip, comprises an immense number of individual atoms, which is fundamental to the functionality of semiconductor devices in electronics.