Mol, molekulyar yoki molyar massa Atom massalarning halqaro birligi

Yechish. 1- usul. Moddaning nisbiy molekulyar massasini hisoblaymiz:

Mr(H₂SO₄)= 2Ar(H) + Ar(S) + 4Ar(O) = 2x1 + 32 + 4x16 = 2 + 32 + 64 = 98 m.a.b.

tenglamadan foydalanib 49 g sulfat kislota necha molni tashkil qilishini hisoblaymiz: mol

2 – usul. Masalani proporsiya usulida ham yechish mumkin.

Dastlab sulfat kislotaning nisbiy molekulyar massasini hisoblaymiz:

Mr(H₂SO₄)= 2Ar(H) + Ar(S) + 4Ar(O) = 2x1 + 32 + 4x16 =

2 + 32 + 64 = 98 m.a.b.

98 g H₂SO₄ ———— 1 mol

49 g H₂SO₄ ———— x mol x=49g∙1mol/98g = 0,5 mol.

3 – masala. Gramm – mol massasi 80 g bo’lgan CuO ning 0,3 mol miqdori qancha gramm bo’ladi?

Dastlab sulfat kislotaning nisbiy molekulyar massasini hisoblaymiz:

Mr(CuO)= Ar(Cu) + Ar(O) = 64 + 16 = 80 m.a.b. yoki gramm/mol

tenglamadan foydalanib mis oksidining massasini (m) hisoblaymiz:

m= н ∙ M = 0,3 mol ∙ 80 g/mol =24 gramm.