Stoichiometry Chemistry Worksheets With Answers Page 6
ADVERTISEMENT
1
2
3
4
5
6
7
8
9
10
11Let’s look at a specific question, involving the Haber process. Basically, this is the process of making
ammonia from the reaction of nitrogen and hydrogen gases. The reaction is shown below:
Molar mass
(28.02)
(2.02)
(17.04)
Balanced equation
N
+
2NH
2
3
3H
2
No. of moles
Amount
Suppose you have a total of 25.0 kg of nitrogen to react with a total of 5.00 kg of hydrogen. What
mass of ammonia can be produced? Which reactant is the limiting reactant? What is the mass of the
reactant that’s in excess? Insert the masses in the correct rows and find the number of moles of both.
Molar mass
(28.02)
(2.02)
(17.04)
Balanced equation
N
+
2NH
2
3
3H
2
No. of moles
892 mol
2475 mol
Amount
25,000 g
5000 g
Start with nitrogen. You have 892 moles of it available, and in order for the nitrogen to react
completely with hydrogen, you’d need 3(892 mol) = 2676 moles of hydrogen, which you don’t have.
Therefore, hydrogen is the limiting reagent. Now let’s answer the other parts of the question. The
mass of ammonia that can be produced is limited by the amount of hydrogen, so do your calculations
based on the number of moles of hydrogen available. Your chart should look like the one below:
(14.02)
(2.02)
(17.04)
Molar mass
Balanced
N
+
2NH
2
3
3H
2
equation
825 mol used
2475 mol
therefore 1650 mol
No. of moles
used
produced
5000 g
1650 mol (17.04) =
Amount
892 mol
23,117 g used
28,116 g produced
25,000g
Chemical Yields
There are three types of yields you’ll need to be familiar with for the SAT II Chemistry test:
theoretical yields, actual yields, and percent yields. Here’s a quick review of what all of these mean to
you. The theoretical yield of a reaction is the amount of product formed once the limiting reactant
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education