The overall redox equation for the voltaic cell can be written as ^^^. What is being reduced in this forward reaction?

Cu⁺² is being reduced in that reaction.

Explanation:

When a substance is reduced, its oxidation number is reduced -changing to a lower value than original-.

Cu⁺² turned into Cu. Meaning that the oxidation number changed from +2 to 0.

Thus, Cu⁺² is being reduced in that reaction.

i'm assuming that it's c.) red bank..

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"