Question

A computer chip contains $1.20\times {10}^{23}$ atoms of silicon. What mass will it have?

• A. 6.02 x 10${}^{23}$ grams
• B. 5.6 grams
• C. 28 grams
• D. 14 grams
• E. 2 grams

Answer 1

The correct option is B 5.6 grams

1 mole of Si is equal to $6.02\times {10}^{23}$ atoms.
$1.20\times {10}^{23}$ atoms of Si correspond to $\frac{1.20\times {10}^{23}}{6.02\times {10}^{23}}=0.199$ moles.
The atomic mass of Si is 28.1 g/mol.
The mass of Si is $28.1g/mol\times 0.199=5.6$ grams.