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- Contributed By: Robert Lucas
This resource is a PowerPoint presentation covering basic stoichiometry problems and how to solve them.
This resource is part of the Chemistry course which contains units on Lab Setup and Safety; Nomenclature; Chemical Reactions and Balancing; Metric Systems & Conversions; Periodic Table and Trends; Atomic Structure; Nuclear Chemistry; Acids, Bases, & Salts; Bonding; Percent Composition; Solutions, Molarity, and Concentrations; Stoichiometry; Energy; Gas Laws; Reaction Rates and Equilibrium; Electron Configuration; and Redox Reactions.
Stoichiometry
mole-mole calculations
6H2O(l) + 6CO2(g) → C6H12O6(s) + 6O2(g)If 8.00 moles of water react with carbon dioxide, how many moles of glucose are produced?
If 6.00 moles of oxygen were produced, how many moles of carbon dioxide were needed to react?
Always use mole-mole ratio somewhere in these problems!!
mole-mass / mass-mole calculations
6H2O(l) + 6CO2(g) → C6H12O6(s) + 6O2(g)What mass, in grams, of carbon dioxide is needed to react with 3.00 mol of water in this reaction?
2Mg(s) + O2(g) → 2MgO(s)
What mass (g) of magnesium oxide is produced from 2.00 mol of magnesium?
C(s) + SO2(g) → CS2(l) + CO(g) (unbalanced)
5C(s) + 2SO2(g) → CS2(l) + 4CO(g) (balanced)
If 8.00g of SO2 reacts, how many moles of each product are formed?
mass/mass calculations
5C(s) + 2SO2(g) → CS2(l) + 4CO(g)How many grams of carbon monoxide are produced from the reaction of 16.0 g of SO2
with carbon?
- If you decompose 500.0 g of sodium chloride, how many grams of sodium are produced?
- If you combust 250.0 g of nonane, how many liters of oxygen are consumed to make the reaction go to completion? Assume STP.
- If you react 450.0 g of copper (II) nitrate with excess calcium, how much copper (II) is produced.
- If you react 400.0 g of ammonium dichromate with excess mercury (I) phosphate, many grams of the mercury containing compound will be formed?
- The equation for photosynthesis is: carbon dioxide + water (with light) = oxygen and glucose (C6H12O6). If 100.0 g of water reacts with excess carbon dioxide, how many liters of oxygen will be produced? Assume STP.
- Using the equation above, what is the minimum number of grams of carbon dioxide that you would need to start with in order to get 1000.0 g of glucose?
- If you start with 5.0 x 1043 molecules of cyclopentane, how many grams of carbon dioxide are produced in this combustion reaction?
- If you start with 3.32 moles of potassium dichromate and you react it with excess lead (IV) iodide, how many moles of the lead compound are produced?
- If you react 37.0 g of calcium chloride with magnesium chromate, how many grams of each product are produced?
- Consider the following question: If you have 47.0 atoms of aluminum sulfate, how many grams of aluminum sulfate do you have? Explain why this is not a stoichiometry problem. Which produces more sodium, the decomposition of 1000.0 grams of sodium chloride or the single displacement reaction of 1000.0 grams of sodium sulfate with excess lead (IV)?
- You begin with 45.76 g of sodium chloride and an unlimited supply of lead (III) oxide. If a reaction does occur, how many grams of the lead (III) chloride are produced? Oh yeah, lead (III) oxide and salt don't react with one another. This is a challenging problem; keep at it!
In this lab, students mix acetic acid and sodium bicarbonate and measure the products.
This resource is part of the Chemistry course which contains units on Lab Setup and Safety; Nomenclature; Chemical Reactions and Balancing; Metric Systems & Conversions; Periodic Table and Trends; Atomic Structure; Nuclear Chemistry; Acids, Bases, & Salts; Bonding; Percent Composition; Solutions, Molarity, and Concentrations; Stoichiometry; Energy; Gas Laws; Reaction Rates and Equilibrium; Electron Configuration; and Redox Reactions.
In this lab, students go around to 6 stations, each of which has a beaker of a different substance. Students calculate how many moles and then how many molecules are in each beaker. This is the handout that students complete, but it also includes some instructions and should be very easy to reconstruct the lab procedures.
This resource is part of the Chemistry course which contains units on Lab Setup and Safety; Nomenclature; Chemical Reactions and Balancing; Metric Systems & Conversions; Periodic Table and Trends; Atomic Structure; Nuclear Chemistry; Acids, Bases, & Salts; Bonding; Percent Composition; Solutions, Molarity, and Concentrations; Stoichiometry; Energy; Gas Laws; Reaction Rates and Equilibrium; Electron Configuration; and Redox Reactions.
- Convert 3.55 x 1024 formula units of sodium chloride to moles.
- Convert 453 grams aluminum sulfate to moles.
- If you have 234 grams of NaOH, how many formula units do you have?
- If you have 5.0 grams of helium gas, how many liters do you have?
This resource includes an explanation of gas stoichiometry. It also provides one solved sample problem, and three practice problems.
This resource is part of the Chemistry course which contains units on Lab Setup and Safety; Nomenclature; Chemical Reactions and Balancing; Metric Systems & Conversions; Periodic Table and Trends; Atomic Structure; Nuclear Chemistry; Acids, Bases, & Salts; Bonding; Percent Composition; Solutions, Molarity, and Concentrations; Stoichiometry; Energy; Gas Laws; Reaction Rates and Equilibrium; Electron Configuration; and Redox Reactions.
- Type of RXN: ______________________
Pb2O3 + Al →
2. Type of RXN: ______________________
NH4Cl → 3. Type of RXN: ________________________
C2H6 + O2 →
PROBLEMS (10pts each!)
4. Mr. Maddin and Donald Williams are working in the lab. They find that the mass of their product was 45g, however, using “stoich” they thought it should be 123g. What was their % yield?
5. Jeremy and Rudy are in the lab (look out!) and they react 500g Iron (III) Sulfide with excess Iodine gas, how many grams of Sulfur do they produce?
6. Ingrid is trying to impress a boy (a boy who shall remain nameless) with her Chemistry knowledge. She combusts 500g of cyclooctane. How many molecules of water did she produce?
7. You begin with 45.76 g of salt and an unlimited supply of Lead (III) Oxide. How many grams of Lead (III) Chloride are produced? Oh yeah, Lead (III) Oxide and salt don’t react with one another.
15% OLD STUFF
- Explain how you balance equations? (2pt)
2. Please write the formula for each of the following: (2pts each)
Calcium Nitrate:
Heptane:
3. Please calculate the total number of atoms in: 3Pb2(SO4)4: (4pts) _____________________
4. Please balance the following equation (5pts)
C6H12 + O2 → CO2 + H2O
NEW STUFF
Multiple Choice: Please select the single best answer in each of the following (3pts each)
5. Which of the following is not a mole of the substance?:
a) 32.000g oxygen gas
b) 12.011 g carbon gas
c) 28.014 g nitrogen gas
d) 4.003 g helium gas
e) All of the above are moles of the substance
6. Fewer steps are required to solve stoichiometry problems when the reactant is given in :
a) grams and the product is sought in grams
b) atoms and the product is sought in moles
c) grams and the product is sought in fu
d) atoms and the product is sought in grams
e) All of the above require the same number of steps
7. When doing chemical reactions in industry, the ............ chemical is often chosen as the excess reagent.
a) Least expensive and most common
b) Most expensive and least common
c) Least expensive and least common
d) Most expensive and most common
e) All are equally likely to be used
8. In the reaction P4 + 5O2 → P4O10, if 2 moles of phosphorus react with 10 moles of oxygen, the theoretical yield of the product will be:
a) 1 mol
b) 2 mol
c) 3 mol
d) 10 mol
e) None of the above
Please convert to scientific notation (2pts each):
9. 343, 930 Please convert to standard notation (2pts):
10. 8.45 x 10-5 __________________________________________________________
- How many seconds are in a decade? (5pts)
- How many seconds are in a decade? (5pts)
PROBLEMS
12. If you have 500g of Potassium Nitrate, how many formula units of it do you have? (8pts)13. If you begin with 150g of Barium Sulfide and react it with excess Sodium Chloride, how much Barium Chloride will you produce? (10pts)
14. Given the balanced equation: NaHCO3 + HCl → NaCl + H2O + CO2, Assume that you start with 10.0g of sodium bicarbonate and you end up with 20.0g of salt, what was your percent yield for this reaction? (10pts)
15. In the balanced reaction: 2Na + 2H2O → 2NaOH + H2, prove which is the limiting reactant if 100.0 g of Na and 50.0 g of H2O are available? (10pts)
16. Please list the steps that you would need to do in order to calculate a % yield? (6pts)
ESSAY QUESTIONS
Please answer 2 of the following 3 questions.17. Explain the importance of coefficients in balanced equations. Please explain what they represent and how they are useful in chemistry. (10pts)
18. You begin with 45.76 g of salt and an unlimited supply of Lead (III) Oxide. How many grams of Lead (III) Chloride are produced? Oh yeah, Lead (III) Oxide and salt don’t react with one another. Explain in words, how you would solve this problem. (10pts)
19. Lurpy is about to receive his PhD in Chemistry from Nutria University (NU). He has but one problem left to work before he gets his degree, but he needs your help. The problem is as such: Lurpy’s new girlfriend Nina synthesized some salt in the lab. She started with 50 grams of chlorine and ended up with 100 grams of salt. Explain why this is a problem and offer reasons (at least 3) for why this may have happened. Don’t let Lurpy down! (10pts)
INSURANCE POINTS
To be added onto your exam total…they can’t hurt you! (2pts each)What is the definition of penultimate? ______________________________________________
What do you have to do to form a salt? ______________________
