Question

caculate the total number of sulphate ions present in 3.92 grams of chromic sulphate is (Cr=52,S=32,0=16)​

Answer 1

Answer:

In Chromium Sulphate, Cr​2(SO4)3, there are 2 moles of chromium ions and 3 moles of Sulphate ions

We know, No. of moles = Molar Mass

Molar Mass of ​Cr​2(SO4)3 = 392 g/mol

Therefore, no. of moles in 3.92 g of ​Cr​2(SO4)3 = 3.92 g392 g/mol = 0.01

mol

So, ​no. of moles of Chromium ions = (2 x 0.01) moles = 0.02 mol

No. of moles of Sulphate ions = (3 x 0.01) moles = 0.03 mol

​Total no. of ions/molecules of Sulphate = no. of moles x Avogadro number=0.03 x 6.023 x 1023 = 0.18069 x 1023 = 1.8069 x 1022

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