Question

Calculate the number of atoms in each of the following:
(i)52 mol of Ar
(ii)52 u of He​

Answer 1

Answer:

Explanation:

Bonjour

(i) 1 mol of Ar = 6.022×1023atoms

∴ 52 mol of Ar = 52×6.022×1023atoms = 3.131×1025atoms

(ii) 1 atom of He = 4 u of He

4 u of He = 1 Atom of He

∴ 52 u of He = 1/4 × 52 = 13 atoms

(iii) 1 mol of He = 4 g = 6.022×1023atoms

∴ 52 g of He = (6.022×1023/4) × 52 atoms = 7.8286×1024atoms

Answer 2

Here is ur answer:

(i) 52 mol of Ar

We know that

Number of atoms (N)= n× N₀

=52× 6.022×10²² atoms= 3.13× 10²⁵ atoms

(ii) 52 u of He

4u of He= 1atom

52u of He= ¼× 52 = 13 atoms

Percentage Composition:

$mass \: \%of \: an \: element \: = \frac{mass \: of \: element \: in \: the \: compound \: }{molar \: mass \: of \: compound } \times 100$