What is the formula mass in amu of KNaC4H4O6 *4H2O

Question

Is it 282.09 amu?

What is the charge on the tartrate anion?

How do I do this?

Answer 1

I looked it up on a web site that calculate molar mass and it is listed as 282.221.
tartrate anion is -2. You can tell it's -2, however, since K is +1 and Na is +1; therefore, C4H4O6 must be -1.
Here is a chart that lists polyatomic ions, their charge, and their formula.
http://www.woodrow.org/teachers/chemistry/links/chem1/PolyatomicIonsChart.html

Answer 2

So the charge for the tartrate anion is -2......But is it possible for me to figure that out with the formula itself? Or is it something that I have to look up.....I saw the link...

Answer 3

First, I made a typo in my first response. "You can tell its -2, however, since K is +1 and Na is +1; therefore, C4H4O6 must be -2". Yes, you can figure it out just that way. Since you know Na is +1 and you know K is +1, then C4H4O6 must be -2 to balance out to zero. All compounds are zero charged. Ions will have a charge.

Answer 4

I am very erect