Question

calculate molar mass and number of molecules for five moles of sulphuric acid.

Answer 1

Molecular mass of H₂SO₄= 1X2+32X1+16X4= 98 gm

(as atomic wt of H=1, S=32, 0=16)

We know that the mass of I mole of molecules is the molar mass of the substance.

Since, 1 mole H₂SO₄ = 6.022 X 10²³ molecules of H₂SO₄

Hence molar mass of 1 mole H₂SO₄ = 6.022 X 10²³ X 98 =59 X 10²⁴ gm.

Thus molar mass of 5 moles of H₂SO₄= 5 X 59 X 10²⁴=29.5 X 10²⁵ gm.

Further no. of molecules of H₂SO₄ in 5 moles= 6.02 X 10²³ X 5= 30 X 10²³ molecules nearly.