Question

1. $3.01 \times 10^{23}$ atoms ni
2. 1000. atoms al

convert to number of atoms

1. 3.00 moles ar
2. 8.50 moles fe
3. 25.0 moles ar
4. 0.00100 mole na
5. 540 grams al
6. 294 grams au
7. 6.35 grams cu
8. 1.00 grams li

Explanation:

Step1: Use Avogadro's number conversion

Recall that 1 mole of any substance contains $6.022 \times 10^{23}$ atoms. Multiply moles of Fe by Avogadro's number.
$$8.50 \text{ mol Fe} \times 6.022 \times 10^{23} \frac{\text{atoms}}{\text{mol}}$$

Step2: Calculate the final value

Perform the multiplication to find the number of atoms.
$$8.50 \times 6.022 \times 10^{23} = 5.1187 \times 10^{24}$$

Answer:

$5.12 \times 10^{24}$ atoms of Fe (rounded to 3 significant figures)