Al2(SO4)3 does the 3 apply to everything or just the SO4. thank you.
The subscript "3" in Al2(SO4)3 indicates that there are three sulfate (SO4) ions in the compound. In this case, the "3" applies only to the sulfate ion (SO4) and not to the entire compound.
To determine how many of each element are present in a compound, you can use a technique called subscripts and coefficients. The subscript is a number written below and to the right of an element symbol in a chemical formula and represents the number of atoms of that element in a compound. In this case, the sulfate ion is (SO4) and it contains one sulfur (S) atom and four oxygen (O) atoms, so the subscript "3" following the (SO4) shows that there are three of these ions in the compound.
The coefficient outside the parentheses indicates how many times the entire compound is present. In this case, the coefficient "2" outside the parentheses means that there are two repeating units of Al2(SO4)3 in the compound.
So, to summarize, the "3" in Al2(SO4)3 applies only to the sulfate ion (SO4) and indicates that there are three sulfate ions in the compound. The coefficient "2" outside the parentheses indicates that there are two repeating units of Al2(SO4)3 in the compound.