Question

(a) What is Avogadro's number? Calculate the number of atoms in 9.2g of
Na (Atomic mass of Na = 23 a.m.u)​

Answer 1

The number of units in one mole of any substance is called Avogadro’s number.

Molar Mass of Na = 23g/mol

9.2g of Na = 9.2/23

= 0.4 mol

1 mol of Na has 6.022×10²³atom

0.4 mol of Na = 0.4×6.022×10²³

= 2.4×10²³atoms

Answer 2

Explanation:

Avgadro's number ----- -------the number of atoms or molecules in one mole of a substance, equal to 6.023×10^23 . we dinote to N(A).

sol------

given that ,

9.2 g , Na= 23 amu

so ,

atomic mass of 1 mole Na = NA× 23 amu

(1 amu = (1/NA )× g)

1 mole Na= NA× (23/ Na) g

1 mole Na=23 g

number of atoms = 9.2 g / 23g

= 0.4 mole

1 mole = 6.023× 10^23 atoms

0.4 mole = 0.4× 6.023× 10^ 23

= 2.40 × 10 ^23 atom ........ write ans

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