What is the chemical formula for cobalt (II) hydrogen carbonate?

1 Answer
Feb 10, 2017

Answer:

The chemical formula for cobalt(II) hydrogen carbonate is #"Co"("HCO"_3)_2#.

Explanation:

The name tells you that this is an ionic compound, made of cobalt(II) ions and hydrogen carbonate ions.

The symbol for the cobalt(II) ion is #"Co"^"2+"#.

The symbol for the hydrogen carbonate ion is #"HCO"_3^"-"# (you have memorized the formulas of the polyatomic ions, haven't you?).

So, the formula contains #"Co"^"2+", "HCO"_3^"-"#.

We need two "-" charges to balance the "2+" charges on the #"Co"#.

Thus, we need two hydrogen carbonate ions, so we enclose the formula in parentheses followed by a subscript 2.

The formula is #"Co"("HCO"_3)_2#