Please help with this chemistry question it’s due by midnight

HF is the limiting reactant

Explanation:

The balanced equation for the reaction is given below:

SiO₂ + 4HF —> SiF₄ + 2H₂O

From the balanced equation above,

1 mole of SiO₂ reacted with 4 moles of HF.

Finally, we shall determine the limiting reactant. This can be obtained as illustrated below:

From the balanced equation above,

1 mole of SiO₂ reacted with 4 moles of HF.

Therefore, 7.5 moles of SiO₂ will react with = 7.5 × 4 = 30 moles of HF.

From the calculation made above, we can see clearly that it will take a higher amount (i.e 30 moles) of HF than what was given from the question (i.e 5 moles) to react completely with 7.5 moles of SiO₂.

Therefore, HF is the limiting reactant and SiO₂ is the excess reactant.

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