You have six half-cells available (all solutions are 1 M). i) CuSO4 solution containing an electrode of Cu
ii) Cr2(SO4)3 solution containing an electrode of Cr
iii) MgSO4 solution containing an electrode of Mg
iv) ZnSO4 solution containing an electrode of Zn
v) AgNO3 solution containing an electrode of Ag
vi) FeSO4 solution containing an electrode of Fe
a) Which pair of half-cells will form the cell with the highest voltage?
b) Which pair of half-cells will form the cell with the lowest voltage?

It will appear as o2(g) as a reactant 

Use the universal gas law formula: pv = nrt now, the key word in this problem is stp, so at stp, temperature will always be 0 degrees celsius and pressure will always be 1.0 atm or 760 torr. given something is at stp, we already know the two variables pressure and temperature. the other thing we can find with the given information is moles. to find moles, just divide grams by molar mass of the element. 16.0g / 2(16.00)g/mol = 0.5 moles plug the values in to the equation pv = nrt (1.0 atm)( x ) = (0.5 )(0+273=273k) the r value is just a constant for when we use atm, liters, moles and kelvin. i'm assuming you want your answer in liters, but if you dont just move the decimal 3 to the right in your final answer. so when plugging these numbers in to your calculator and trying to find x, you get 11.20665 liters using significant figures the answer is 11.2 liters