Question

Aluminum metal reacts with zinc(II) ion in an aqueous solution by the following half-cell reactions:
Al(s) → Al3+(aq) + 3e−
Zn2+(aq) + 2e− → Zn(s)

a. Predict the potential of the cell under standard conditions.
b. Predict whether the reaction will occur spontaneously, or whether a source of electricity will be required for the reaction. Justify your answer
c. In terms of the metals involved, predict the direction electrons will flow in the reaction
Predict which electrode will lose mass and which will gain mass.

as a side note I get most of the question but I'm lost when we calculate the E cell value and why the value doesn't equal - 2.12

Answer 1

could you explain how you got -2.12? looking at a standard reduction potential table I get 1.66V for the Al reaction and -0.76 for the Zn2+ reaction. you have to flip the sign on the Al potential because we're using the reverse of the reaction stated on the table.

table for reference: https://www.flinnsci.com/globalassets/flinn-scientific/all-product-images-rgb-jpegs/ap7041.jpg