Final answer:
To find the number of silicon atoms in a 1.05×10³ g sample, you must calculate the moles of silicon using its molar mass and then multiply by Avogadro's number. The correct value is not listed in the options; it is 2.25 × 10²µ atoms Si.
Step-by-step explanation:
To calculate the number of atoms in a 1.05×10³ g sample of silicon, we first have to determine the moles of silicon in the sample. This can be done using the molar mass of silicon (≈ 28.09 g/mol).
To find the moles of silicon, we divide the sample mass by the molar mass:
1.05×10³ g Si ÷ 28.09 g/mol Si = 37.38 mol Si.
Then, to find the number of atoms, we use Avogadro's number (6.022 × 10²³ atoms/mol):
37.38 mol Si × 6.022 × 10²³ atoms/mol = 2.25 × 10²µ atoms Si.
The answer closest to this result from the options provided is:
A. 6.022 × 10²³
but it does not match the correct calculation. Based on the given information, the choices do not include the correct value.