How many moles are and how many atoms contain: a) 8g sulfur S; b) 280g Iron Fe; c) 3.2 kg of copper Cu?

Decision:
1. The molar mass of sulfur is 32, iron is 56, copper is 64.
2. Let’s find the amount of substance in sulfur:
8/32 = 0.25 mol;
3. Find the number of sulfur atoms by multiplying the amount of matter by Avogadro’s number:
0.25 * 6.02 * 10 ^ 23 = 1.505 * 10 ^ 23 = 1505 * 10 ^ 20 atoms;
4. Find the amount of substance in iron:
280/56 = 5 mol;
5. Find the number of atoms in iron:
5 * 6.02 * 10 ^ 23 = 30.1 * 10 ^ 23 = 301 * 10 ^ 22 atoms;
6. Find the amount of substance in copper:
3200/64 = 50 mol;
7. Find the number of atoms in copper:
50 * 6.02 * 10 ^ 23 = 301 * 10 ^ 23 atoms;
Answer:
a) 0.25 mol of sulfur contains 1505 * 10 ^ 20 atoms;
b) 5 moles of iron contain 301 * 10 ^ 22 atoms;
c) 50 moles of copper contain 301 * 10 ^ 23 atoms.