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Calculate the number of atoms in a 1.05×10³g sample of silicon.

A. 6.022 x 10²3
B. 1.05 x 10³
C. 2.018 x 10³
D. 3.14 x 10³

User Mau Ruiz
by
7.5k points

1 Answer

4 votes

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.

User Friday
by
8.8k points
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