Final answer:
To find the number of atoms in a sample of plumber's solder, calculate the molar mass of the alloy and divide the mass of the sample by the molar mass. The sample contains 67% lead and 33% tin, with molar masses of 207 g/mol and 118.7 g/mol respectively. Using Avogadro's number, the number of atoms in the sample is approximately 2.57 x 10^23 atoms.
Step-by-step explanation:
The number of atoms in a sample can be calculated using Avogadro's number and the molar mass of the compound. In this case, plumber's solder is a lead-tin alloy.
To find the number of atoms, we need to determine the molar mass of the alloy and divide the mass of the sample by the molar mass.
The molar mass of lead (Pb) is 207 g/mol and the molar mass of tin (Sn) is 118.7 g/mol. Since the sample contains 67% lead,
we can calculate the molar mass of the alloy: (0.67 * 207 g/mol) + (0.33 * 118.7 g/mol) = 175.19 g/mol.
Now, we can calculate the number of moles in the sample: 75 g / 175.19 g/mol = 0.427 moles.
Finally, using Avogadro's number (6.022 x 10^23 atoms/mol), we can calculate the number of atoms: 0.427 moles * (6.022 x 10^23 atoms/mol) = 2.57 x 10^23 atoms.