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Question
Which has more number of atoms, 100 grams of sodium or 100 grams of iron (given, atomic mass of Na = 23 u, Fe = 56 u)?
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Solution
Atomic mass of Na = 23 u (Given)
Then, gram atomic mass of Na = 23 g
Now, 23 g of Na contains = 6.022 x 1023 number of atoms
`"Thus, 100 g of Na contains "=(6.022xx10^(23))/23xx100" number of atoms"`
= 2.6182 x 1024 number of atoms
Again, atomic mass of Fe = 56 u(Given)
Then, gram atomic mass of Fe = 56 g
Now, 56 g of Fe contains = 6.022 x 1023 number of atoms
`"Thus, 100 g of Fe contains "=(6.022xx10^(23))/56xx100" number of atoms"`
= 1.0753 x 1024 number of atoms
Therefore, 100 grams of sodium contain more number of atoms than 100 grams of iron.
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