What is the density of an object with a volume of 12 mL and a mass of 38g? What is the mass of an object with a density of 0.29 g/mL and a volume of 176.5 mL?
What is the volume of an object with a mass of 42.6 g and a density of 6.73 g/mL?
What is the density of an object with a volume of 27 mL and a mass of 13.79?
What is the mass of an object with a density of 0.92 g/mL and a volume of 136.5 mL?

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

it means there are 3 atoms of oxygen

explanation:

0.07 g/cm³

1.37 g/cm³