Question

how many iron atoms are contained in 354 g of iron?
2.62 × 1025 fe atoms
9.50 × 1022 fe atoms
2.13 × 1026 fe atoms
3.82 × 1024 fe atoms
4.69 × 1024 fe atoms
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Explanation:

Step1: Calculate the number of moles of Fe

The molar mass of Fe (iron) is \(M = 55.85\space g/mol\). The mass of Fe is \(m=354\space g\). The number of moles \(n=\frac{m}{M}\), so \(n=\frac{354\space g}{55.85\space g/mol}\approx6.34\space mol\).

Step2: Calculate the number of atoms

According to Avogadro's number \(N_A = 6.022\times 10^{23}\space mol^{-1}\). The number of atoms \(N=n\times N_A\). Substitute \(n = 6.34\space mol\) and \(N_A\) into the formula: \(N=6.34\times6.022\times 10^{23}\).
\(N=(6.34\times6.022)\times 10^{23}\approx 3.82\times 10^{24}\)

Answer:

3.82×10²⁴ Fe atoms