Step-by-step explanation:
Before we find the number of particles, we have to find the number of moles that are present in 500 g of Cu₂S using the molar mass of it.
molar mass of Cu = 63.55 g/mol
molar mass of S = 32.07 g/mol
molar mass of Cu₂S = 2 * 63.55 g/mol + 1 * 32.07 g/mol
molar mass of Cu₂S = 159.17 g/mol
mass of Cu₂S = 500 g
moles of Cu₂S = 500 g/(159.17 g/mol)
moles of Cu₂S = 3.14 moles
According to Avogadro's Number there are 6.022 *10^23 particles in 1 mol of Cu₂S. Let's use that relationship to find the answer to our problem.
1 mol of Cu₂S = 6.022 * 10^23 particles
number of particles = 3.14 moles * 6.022 *10^23 particles/mol
number of particles = 1.89 *10^24 particles
Answer: There are 1.89 *10^24 particles in 500 g of Cu₂S.