To calculate the molar masses of Al(C_2H_3O_2)_3, we must take all the molar mass of the elements present.
We have C_2,H_3,O_2 three times, and one Al atom.
C_2 has the molar mass of two carbon atoms, that is 12*2=24 \ "g/mol".
H_3 has a molar mass of three hydrogen atoms, that is 1*3=3 \ "g/mol".
O_2 is oxygen gas, and has the mass of two oxygen atoms, and that'll be 16*2=32 \ "g/mol".
So, the total mass of C_2H_3O_2 will be 24+3+32=59 \ "g/mol". But, we have (C_2H_3O_2)_3. so we need to multiply the mass by 3, and we get 59*3=177 \ "g/mol".
Final step is add the ,olar mass of aluminium, that is 27 \ "g/mol".
So, the total mass of this compound is 177+59=236 \ "g/mol".
