Sample Problem 3.1
Calculating the Mass and the Number of Atoms in a Given Number of Moles of an Element
PLAN:
SOLUTION:
(a) Silver (Ag) is used in jewelry and tableware but no longer in US coins. How many grams of Ag are in 0.0342 mol of Ag?
(b) Iron (Fe), the main component of steel, is the most important metal in industrial society. How many Fe atoms are in 95.8 g of Fe?
(a) To convert mol of Ag to g, we use the number of g Ag per mol Ag, the molar mass M.
(b) To convert g of Fe to atoms we first find the number of moles of Fe and then convert moles to atoms.
0.0342 mol Ag x
= 3.69 g Ag
PLAN:
SOLUTION:
95.8 g Fe x
= 1.72 mol Fe
1.72 mol Fe x
= 1.04 x1024 atoms Fe
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