Writing The Formula for Aluminum Sulfate


Writing The Formula for Aluminum Sulfate

Find the formula for aluminum sulfate. Aluminum is Al+3. Sulfate is SO4-2. The generic equation is (Al+3)x(SO4-2)y. Again there are many pairs of subscripts that will allow the result to be zero: 8:12, 6:9, 4:6 and 2:3. The lowest ratio is 2:3.The charges add to zero: 2(+3 +3(-2)=0. That will give us (Al+3)2(SO4-2)3. The Al+3 is not polyatomic and therefor never requires the use of parenthesis. The SO4-2 is polyatomic and requires the use of parenthesis, if the subscript is bigger than “1". The final equation is Al2(SO4)3


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