Question

3. Define Avogadro's Number: 4. Write the Avogadro's number 602 000 000 000 000 000 000 000 in scientific notation. 5. What is a mole? 6. Calculate each of the following (Show Work): a the number of C atoms in 0.5 mol of C b. the number of so molecules in 1.28 mol of SO2 c. the moles of Fe in a simple containing 5.22 x1022 atoms of Fe 7. Calculate the molar mass for each of the following. Use the periodic table for the atomic mass (Show Work) Fe₂O3 P₂O5 Mg(OH)2 H2SO4 8. How many moles of Cl, are there in 25 g of Cl, (Show Work)? 9. How many moles of so, are there in 125 g of So, (Show Work)? 10. How many moles of H2SO4 are there in 98 g of H2SO4 (Show Work)?

Answer 1

3. Avogadro's number is defined as the no of C(carbon) atoms in 12 g of C sample or the number of atoms or molecules in one mole of a substance.

4. 6.03 x 10^23

5. Mole is the SI unit of amount of a substance. It equals 6.02 x 10^23 units of a substance.

6)a) .5 moles = .5 x 6.02 x 10^23 atoms of C

= 3.01 x 10^23 atoms of C

b) 1.28 moles =1.28 x 6.02 x 10^23 atoms of SO2

= 7.71 x 10^23 atoms of SO2

c) 5.22 x 10^22 atoms =(5.22 x 10^22)/(6.02 x 10^23)

= .087 moles of Fe