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

Asked by  | 12th Jan, 2013, 10:30: AM

Expert Answer:

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.

Answered by  | 13th Jan, 2013, 12:12: PM

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