7which physical characteristic of a solution may
indicate the presence of a transition element?
(1) its density
(2) its color
(3) its effect on litmus
(4) its effect on phenolphthalein

2= its color

Explanation:

Transition elements are present in the middle of periodic table. These are d-block elements.

These are 38 elements.

All transition elements have partially filled d orbitals.

They showed color in compound because of d-d transition.

During the d-d transition electron absorbed the energy and emit the reminder energy. The emission is usually in the form of color light.

The color of ion is complementary to the absorbed color.

The transition elements are used as a catalyst in industries such as polymer, petroleum industries.

They are ductile, conduct heat and electricity.

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

i would say b

explanation:

but i think i would need more information than that