Question

question 7 (10 points) how many atoms are in 2.50 g of silicon (si) a 5.36x10^22 b 9.81x10^21 c 6.02x10^22 d 2.50x10^23

Explanation:

Step1: Find molar mass of Si

Molar mass of Si = $28.09\ \text{g/mol}$

Step2: Calculate moles of Si

$\text{Moles} = \frac{\text{Mass}}{\text{Molar Mass}} = \frac{2.50\ \text{g}}{28.09\ \text{g/mol}} \approx 0.0890\ \text{mol}$

Step3: Calculate number of atoms

$\text{Atoms} = \text{Moles} \times N_A = 0.0890\ \text{mol} \times 6.022\times10^{23}\ \text{atoms/mol} \approx 5.36\times10^{22}\ \text{atoms}$
(where $N_A$ is Avogadro's number)

Answer:

a. $5.36\times10^{22}$