Question

Example 3.5 Calculate the number of
particles in each of the
following
(i) 46 g of Na atomas (number from
mass)
(ii) 8 g 0, molecules (number of
molecules from mass)
(iii) 0.1 mole of carbon atoms (number
from given moles)​

Answer 1

Answer:

8g 0,molecules (number of molecules. from mass)

Answer 2

Answer:

BELOW ↓

Explanation:

i) We know , no. of atoms in a substance = n×N(A)

for 'n'= no. of moles = (weight/mass)

we know , molar mass of Na is = 23g/mole

therefore, AQ:-

(46/23)×(6.022×10²³)

Ans = 12.044 × 10²³ atoms in 46g of Na.

ii) No. of MOLECULES in 8g of O2 = n × N(A)

Molecular mass of O2 => 2(16) = 32g/mole.

therefore, AQ:-

=(8/32)×(6.022×10²³)

=(6.022×10²³)/4

Ans = 1.51 × 10²³ molecules in 8g of O2.

iii) No. of C atoms in 0.1 mole = n × N(A).

therefore, AQ:-

=0.1 × 6.022 × 10²³

ANS = 6.022 × 10²² atoms of C in 0.1 mole of C element.

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