I'm given the following tables and question 3 asks to determine the formula for the copper gluconate.

I'm given the following tables and question 3 asks to determine the formula for the copper gluconate. But it's my understanding that I would need either the molar mass of the gluconate, or the ratio of oxygen in the formula to answer this. I even asked my professor and he just said "You should just calculate the "empirical formula" not the actual formula". What? How am I supposed to determine this without looking elsewhere for the gluconate formula?

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