Question

aluminum - find the mass of the aluminum foil.
a) calculate the number of moles in the sample.
b) calculate the number of aluminum atoms in the sample.

Explanation:

Step1: Calculate the number of moles

The formula for calculating the number of moles \(n\) is \(n=\frac{m}{M}\), where \(m\) is the mass and \(M\) is the molar mass.
Given \(m = 0.04\space g\) and \(M=26.9815\space g/mol\)
\(n=\frac{0.04}{26.9815}\approx1.48\times10^{-3}\space mol\)

Step2: Calculate the number of atoms

Use Avogadro's number \(N_A = 6.022\times 10^{23}\space atoms/mol\). The number of atoms \(N=n\times N_A\)
Substitute \(n = 1.48\times 10^{-3}\space mol\) into the formula:
\(N=(1.48\times 10^{-3})\times(6.022\times 10^{23})\)
\(N = 8.91\times10^{20}\space atoms\)

Answer:

a) The number of moles is approximately \(1.48\times 10^{-3}\space mol\)
b) The number of aluminum atoms is approximately \(8.91\times 10^{20}\space atoms\)