20. the mass of one mole of lead (pb) atoms is 207.2 g. use a proportion to calculate the n
lead atoms in a 15.00 g sample of lead.
2. y
i n the mathematical relationship between atomic mass units (amu) and grams (g)?

a) atoms Pb = 4.3595 E22 amu

b) g = ( 6.022 E23 amu ) × ( Mw )

Explanation:

sample:

∴ m = 15.00 g

a) atoms Pb = ?

⇒ atoms Pb = (15.00g Pb)(mol Pb/207.2 g)(6.022 E23 amu/mol)

⇒ atoms Pb = 4.3595 E22 amu

b) relationship:

∴ 1 mol (n) ≡ 6.022 E23 amu(1)

∴ mass (g) ≡ (Mw)×(n)

⇒ n = g / Mw(2)

∴ Mw: molecular weight

(1) = (2):

⇒ g / Mw ≡ 6.022 E23 amu

⇒ g ≡ ( 6.022 E23 amu ) × ( Mw )