Why would dry cleaners use nonpolar tetrachloroethylene, c2cl4, to get cheeseburger grease out of your clothes?
it is a solvent.
it is fat-soluble.
it is water-soluble.
it is a solute.
it would not get out the grease.

                    It is fat-soluble

                         The cheeseburger grease adhered to cloths can not be washed by simple rinsing it with water. This is because of the fact that "Like Dissolves Like". As grease is non-polar in nature therefore it will show no interaction with water because water is polar in nature. Hence, in order to make interactions of grease we must add some sort of non polar solvent like Tetrachloroethylene (C₂Cl₄). Now, both being non-polar in nature will interact, make attractions and grease will happily leave with Tetrachloroethylene leaving the cloth clean again.

                   Tetrachloroethylene is non polar because the four chlorine atoms about the double bond cancel out each others effect making the dipole moment zero hence, the overall molecule becomes non-polar.

first, consult an activity series chart to determine if al is more reactive than fe. it is, so it will replace the fe. now, one can continue with the problem.

next, make sure you have a correctly balanced equation.

3feo + 2al ==> 3fe + al2o3

now, determine which reactant (feo or al) is in limiting supply.

moles feo present = 125 g x 1 mole/71.8 g = 1.74 moles

moles al present = 25.0 g x 1 mole/26.98 g = 0.927 moles

since from the balanced equation, it take 3 mol feo for every 2 mol al, al will be limiting.

you can determine this simply by dividing moles of each by their coefficient in the balanced equation. for example: 1.74/3 = 0.58 and 0.927/2 = 0.464. al is less, so it is limiting.

finally, using the stoichiometry in the balanced eq. determine mass of fe that can be produced from 0.927 moles of al.

0.927 moles al x 3 moles fe/2 moles al x 55.8 g/mole = 77.6 g