SCH3U Mole & Avogadro S Number

SCH4C Mole & Avogadro’s Number

Recall that the mole is a unit that is used to make equations easier to work with. One mole of any substance occupies 22.4 L of space at 101.3 kPa of pressure & a temperature of 273.15 K (0 C). According to Avogadro there are 6.023 x 1023 particles for a mole of any substance. We can use the mole to determine the masses of substances within equations or the number of particles involved. Here are some questions to get started:

1. What is the number of atoms in 1 mole of Na (s)?

2. What is the number of atoms in 1 mole of Cl2 (g) ? 3. What is the number of molecules in 1 mole of NaCl? 4. What is the number of atoms in 1 mole of NaCl?

5. What is the number of atoms in 1 mole of CaCO3? 6. What is the number of molecules in 1 mole of Na2SO4? 7. What is the number of atoms in 1 mole of Na2SO4? 8. How many moles are there of Na if there are 6.02 x 1023 atoms? 23 9. How many moles are there of Cl2 if there are 6.02 x 10 atoms? 23 10. How many moles are there of Na2SO4 if there are 6.02 x 10 atoms? 11. What is the molar mass of H2 (g) ? 12. What is the molar mass of O2 (g) ? 13. What is the molar mass of H2O (l)? 14. What is the molar mass of H2SO4 (aq) ?

15. What is the molar mass of Na3PO42H2O (s) ? 16. What is the mass of 3.0 moles of salt (NaCl)?

17. What is the mass of 4.5 moles of C6H12O6? 18. What is the mass of 0.5 moles of sodium phosphate? 19. How many moles of lithium oxide are there in a 29.8 g sample? 20. How many moles of silver nitrate are there in a 339.8 g sample?

Solutions:

1. 6.02 x 1023 atoms 2. 1.20 x 1024 atoms 3. 6.02 x 1023 molecules 4. 1.20 x 1024 atoms 5. 3.01 x 1024 atoms 6. 6.02 x 1023 molecules 24 7. 4.21 x 10 atoms 8. 1.0 moles 9. 0.5 moles 10. 0.143 moles (1/7th) 11. 2.0 g/ mol 12. 32.0 g/mol 13. 18.0 g / mol 14. 98.0 g/mol 15. 199.1 g/mol 16. 3.0 moles x 58.5 g/mol = 175.5 grams 17. 4.5 moles x 180.0 g/mol = 810.0 grams 18. 0.5 moles x 164.0 g/mol = 82.0 grams 19. 29.8 grams / 29.8 g/mol = 1.0 moles 20. 339.9 grams / 169.9 g/mol = 2.0 moles