Question

The atomic mass of calcium is 40u.what will be the no. of calcium atoms in 0.4 u of calcium ? Explain how?

Answer 1

first find no of mole
no of mole=given weight /atomic weight
=0.4u/40u=1/100=0.01
we know 1mole =6.023 x 10^23 atoms of substance
hence 0.01 mole contains =6.023 x 10^21 atoms of calcium.

Answer 2

Given ;
mass of calcium = 0.4 u
Atomic mass = 40u

No. of atoms = (given mass/Atomic no.) × N•
= (0.4/40) × 6.022×10^23
= (1/100) × 6.022 × 10^23
= 6.022 × 10^21 atoms
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