Question

Calculate the relative molecular mass of sodium tetraoxosulphate (iv), Na²SO⁴

Answer 1

Answer:

Answer is 142 g/mol

Explanation:

Na2SO4

(2×23)+(32)+(4×16)

46+32+64

142

Answer 2

Proper Question: Calculate the relative molecular mass of sodium tetraoxosulphate (Na₂SO₄).

Answer: the relative molecular mass of sodium tetraoxosulphate (Na₂SO₄) is equal to 142 u.

Given:

The molecular formula of sodium tetraoxosulphate is (Na₂SO₄).

To Find:

The relative molecular mass of sodium tetraoxosulphate (Na₂SO₄).

Solution:

The relative masses of atoms and molecules is equal to the number of times the given atom or molecule is heavier than  $\frac{1}{12}th$  of the mass of one C-12 atom. The unit of relative atomic mass is amu and it is denoted by 'u'.

        $\therefore Relative \:atomic\:mass=\frac{Average\:mass\:of\:1\:atom\:of\:the\:substance}{(\frac{1}{12} th\:of\:the\:mass\:of\:one\:C-12\:Carbon\:atom)}$

→ As the relative atomic mass is a ratio therefore it is a dimensionless quantity.

→ The relative atomic mass of the Sodium atom (Na) = 23 u

→ The relative atomic mass of the Sulphur atom (S) = 32 u

→ The relative atomic mass of the Oxygen atom (O) = 16 u

→ The relative molecular mass of Na₂SO₄:

   = 2 × (23) + 32 + 4 × (16) = 46 + 32 + 64 = 78 + 64 = 142 u

Therefore the relative molecular mass of sodium tetraoxosulphate (Na₂SO₄) is equal to 142 u.

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