Science pls help

Question

Using the balanced equation 3Ba+Al2(SO4)3-->2Al+3BaSO4, what is the limiting reactant if 1 g of Ba reacts with 1.8g of Al2(SO4)3?

 

 

Using the balanced equation 3Ba+Al2(SO4)3-->2Al+3BaSO4, if 4 g Ba react .45 g Al2(SO4)3, what is the limiting reactant?

 

Using the balanced equation 3Ba+Al2(SO4)3-->2Al+3BaSO4, if 1 g of Ba reacts with 1.8 g Al2(SO4)3, what is the excess reactant?

 

Using the balanced equation, 2C2H6 +7O2 -->4CO2 +6H2O, if 2.5g C2H6 react with 170g O2, what is the excess reactant?

 

Using the balanced equation 3Ba+Al2(SO4)3-->2Al+3BaSO4, if 4g Ba react with .45g Al2(SO4)3, what is the excess reactant?

In the equation: FeCl3+O2-->Fe2O3+Cl2, how many moles of chlorine gas can be produced if 4 moles of FeCl3 react with 4 moles of O2?

 

 

In the balanced equation 2C2H6 +7O2 -->4CO2 +6H2O, if 10g of C2H6 react with 42.5g O2, what is the excess reactant?

Answer 1

Most of these questions are the same, and deal with identifying the limiting reactant/reagent. Once you know how to do one, you can do them all. For each, calculate the moles of each reactant. Then divide that by the coefficient in the balanced equation. The one that is the lowest is the limiting reactant, and the other is the one in excess.  Here is ONE example. You should be able to do the others using the same procedure.

 

3Ba + Al₂(SO₄)₃ ==> 2Al + 3BaSO₄, what is the limiting reactant if 1 g of Ba reacts with 1.8g of Al₂(SO₄)₃?

Find moles of each reactant:

moles Ba = 1 g Ba x 1 mole/137 g = 0.00730 moles Ba

moles Al₂(SO₄)₃ = 1.8 g x 1 mole/342 g = 0.00526 moles aluminum sulfate

Divide each by the coefficient and see which is less:

0.00730 moles Ba/3 = 0.00240

0.00526 moles aluminum sulfate/1 = 0.00526

Ba is limiting.

Since Ba is limiting, aluminum sulfate must be the one in excess.

 

Do all others the same way.

 

The other type of problem is where they ask you to find the number of moles of product that can be produced. Again, you must find the limiting reactant, and then use that to predict the amount of product formed. Here is the problem from above.

 

FeCl₃ + O₂ ==>Fe₂O₃ + Cl₂,  how many moles of chlorine gas can be produced if 4 moles of FeCl₃ react with 4 moles of O₂?

First, you MUST BALANCE the equation. It is NOT balanced as presented.

4FeCl₃ + 3O₂ ==> 2Fe₂O₃ + 6Cl₂ This is the balanced equation.

Find limiting reactant:

4 moles FeCl₃/4 = 1 mole

4 moles O₂/1 = 4

The value for FeCl₃ is less, so it is limiting and O₂ is in excess.

Moles of Cl₂ produced = 4 moles FeCl₃ x 6 moles Cl₂/4 moles FeCl₃ = 6 moles Cl₂ gas produced.