Question

1. the number of atoms in 2.0 mol of al is

a. 2.0 al atoms
b. 3.0 x 1023 al atoms
c. 1.2 x 1024 al atoms

1. the number of moles of s in 1.8 x 1024 atoms of s is

a. 1.0 mol of s atoms
b. 3.0 mol of s atoms
c. 1.1 x 1048 mol of s atoms

Explanation:

Step1: Recall Avogadro's number

Avogadro's number \(N_A = 6.02\times10^{23}\text{ atoms/mol}\)

Step2: Calculate the number of Al atoms

For \(n = 2.0\text{ mol}\) of \(Al\), use the formula \(N=n\times N_A\).
\(N = 2.0\text{ mol}\times6.02\times 10^{23}\text{ atoms/mol}=1.204\times10^{24}\text{ atoms}\approx1.2\times 10^{24}\text{ atoms}\)

Step3: Calculate the number of moles of S

For \(N = 1.8\times10^{24}\text{ atoms}\) of \(S\), use the formula \(n=\frac{N}{N_A}\)
\(n=\frac{1.8\times 10^{24}\text{ atoms}}{6.02\times10^{23}\text{ atoms/mol}}\approx3.0\text{ mol}\)

Answer:

1. C. \(1.2\times 10^{24}\text{ Al atoms}\)
2. B. \(3.0\text{ mol of S atoms}\)