Question

calculate the number of moles of.
(1) calculate the atom infigram 5g of cl atomic mass of calcium 4u​

Answer 1

Explanation:

(i) 1 mole of Ar =6.022×10

23

atoms of Ar

52 mol of Ar=52×6.022×10

23

atoms of Ar

=3.131×10

25

atoms of Ar

(ii) Atomic mass of He = 4amu

Or

4amu is the mass of He atoms = 1

Therefore 52 amu is the mass of He atoms=0.25×52=13 atoms of He

(iii) Gram atomic mass of He = 4g

Or

4g of He contains =6.022×10

23

atoms

Therefore 52 g of He contains=

4×52

6.022×10

23

=7.83×10

24

atoms