Question
Sat January 12, 2013 By:
1)Calculate the mass id 1 atim of gold(Take atomic nass if gold as 200).
 
2)Calculate the number of the constituent atoms in 53g of 

Dear TopperLearning team Please help in the following questions related to mole concept.Please explain each and every question step wise and clearly please.

Expert Reply
Sun January 13, 2013
For a molecule,
1 mole = Gram molecular mass  = 6.022 x 1023 molecules
Like for the following given data

Volume of water = 0.18 ml
Assuming density of water = 1g/cm3
 0.18 ml = 0.18 gm
Molar mass of water = 18 gm
Therefore 18 gm= 1mole
0.18 gm= 1X 0.18/18 =.01 mole
1 mole= 6.022 X 1023 molecules
0.01 mole = 6.022 X 1021 molecules
Relation between moles nad molecules
There is relation between moles and molecules as,
1 mole =6.02 x 1023 molecules
molecules is formed by two atoms and mole is a number which counts the no. of molecules or atoms.
 
 
1. The molecular weight of gold is 200 (given), then you would divide it by the number of atoms in a mole (6.22 x 1023), which gives you a mass of 33.211 x 1023.
 
2. Total mass = 2(23) + 1(12) +3(16) = 46+12+48 = 106 u
 
 
No of Mole = 53/106 = 1/2

no. of atoms of Na = 1/2 x Avogadro no. x 2
no. of atoms of C = 1/2 x Avogadro no.
no. of atoms of O = 1/2 x avogadro no. x 3
 
4. 

We know

5. 

23 g of sodium (1 mole) has atoms = 6.022 ? 1023

:.100 g of sodium has atoms = 6.023 ?1023 ?100/ 23 = 2.617 ? 1024 atoms



56 g of iron (1 mole) has atoms = 6.022 ? 1023

:. 100 g of iron has atoms = 6.022 ? 1023?100/ 56 = 1.075 ? 1024 atoms



:. 100 g of sodium has more atoms than 100 g of iron.

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