Question

Calculate the molar mass of al2(cro4)3

Answer 1

Molar mass  of Al₂(CrO₄)₃ is the mass of  one mole of  Al₂(CrO₄)₃
one mol =weight of Al₂(CrO₄)₃  in g /one mol
1) We have to find the atomic mass (in a periodic talbe) of the following elements  (in u)
Al=26.98 u
Cr=52 u
O=16 u

2)We calculate the atomic weight of Al₂(CrO₄)₃
Atomic weight (Al₂(CrO₄)₃)=2(26.98 u)+3[(52 u)+4(16 u)]=
=53.96 u+3(52 u+64 u)=53.96 u+3(116 u=53.96 u+348 u=401.96 u

3) One mole of (Al₂(CrO₄)₃ ) have 401.96 g of Al₂(CrO₄)₃ 

molar mass=401.96 g/ mol

answer: 401.96 g/ mol