Limiting Reactants

Using the idea of a limiting reactant, answer the following exercises:

1.  Ammonia (NH3) can be formed from the elements N2 and H2, as shown: N2 + 3H2 ® 2 NH3

a.  How many moles of ammonia can be made from one mole of N2 and 3 moles of H2?

b.  Suppose we had 3 moles each of the N2 and H2 available to react. Which of the reactants would be the limiting reagent? How many moles of ammonia could we make? Would any of the reactants be left over? How many moles?

c.  How many moles of ammonia could we make from one mole each of N2 and H2?

2.  Iron and oxygen combine to produce iron (III) oxide.

Write a balanced equation in the box below, then complete the columns of the data table.

Use the space below to show your work J

Ingredients / Number of
Iron (III) oxide possible / Total number
Iron (III) oxide made / Remaining
Ingredients / Limiting
Reactant
30 moles iron
25 moles oxygen / ______
______/ ______
______

3.  Nitrogen and hydrogen gas combine to produce ammonia (NH3).

Write a balanced equation in the box below then complete the data table.

Use the space below to show your work J

Ingredients / Number of
Ammonia possible / Total number
Ammonia made / Remaining
Ingredients / Limiting
Reactant
12 moles nitrogen gas
15 moles hydrogen gas / ______
______/ ______
______

4.  Hydrogen gas and oxygen gas produce water.

Write a balanced equation in the box below then complete the data table.

Use the space below to show your work J

Ingredients / Number of
Waters possible / Total number
Waters made / Remaining
Ingredients / Limiting
Reactant
6.7 moles hydrogen gas
7.7 moles oxygen gas / ______
______/ ______
______

------STOP HERE ------

5.  Given the balanced chemical equation: 2NO(g) + O2(g) ® 2NO2(g)

Calculate the mass of nitrogen dioxide that can be made from 30.0 grams of NO and 30.0 grams of O2. First calculate the moles of each compound to determine the moles of NO2 that could be produced.

6.  Zinc and iodine react to form zinc (II) iodide (the reactants and the product are all solids at room temperature).

a)  Write a balanced chemical equation for this reaction. Remember to ask your self if any of the individual elements (the reactants) are one of the seven diatomic elements.

b)  Suppose that 50.0 g of zinc and 50.0 g of iodine are used to form zinc (II) iodide.

1)  Assuming that the reaction goes to completion, which element will be totally consumed in the formation of the zinc (II) iodide?

2)  What is the limiting reagent?

3)  How many grams of zinc (II) iodide can be produced?

4)  How many grams of the excess element remain unreacted?