A standard galvanic cell is constructed so that the overall cell reaction is as given below where M is an unknown metal. 2 Al3+(aq) + 3 M(s) 3 M2+(aq) + 2 Al(s) If ΔG° = -411 kJ for the overall cell reaction, identify the metal used to construct the standard cell.

magnesium metal

Explanation:

According to the redox reaction equation, six electrons were transferred hence n=6 and F= Faraday's constant 96500C. ∆G° is given hence E°cell can easily be calculated as follows:

From ∆G°= -nFE°cell

E°cell= -∆G°/nF= -(-411×10^3/96500×6)

E°cell= 0.7098V

But for Al3+(aq)/Al(s) half cell, E°= -1.66V from standard table of reduction potentials.

E°cell= E°cathode- E°anode but Al3+(aq)/Al(s) half cell is the cathode

Hence

E°anode=E°cathode - E°cell

E°anode= -1.66-0.7098= -2.37V

This is the reduction potential of Mg hence the anode material was magnesium metal

rosa was looking for patterns to predict the products of chemical reactions. she recorded three similar decomposition reactions in the table.she should record 2licl + 3o2.

in the last row of the table. it is the thermal decomposition of chlorate lithium, hence, she should record these products as: lithium chloride ( 2licl ) and oxygen ( 3o2 )   2 > 2 licl + 3o2.