CHAPTER 11: STOICHIOMETRY - Livingston
| |
|[pic] |
|Chapter 12 |
|Stoichiometry Notes Packet |
|Big Picture Ideas: |
|The identity of the reactants helps scientists to predict the products in a chemical reaction. |
|Quantitative relationships exist with all chemical reactions that allow scientists to predict amounts of products formed, reactants consumed, and |
|percent yield based on theoretical maximum. |
|Big Picture Questions: |
|How can quantitative relations in chemical reactions be translated to real-life industry situations? |
|How can you predict the products in a chemical reaction?o |
|Suggested Resources… |Formative Assessments |
|Homework Assignments |Classwork Assignments |
|Laboratory Activities |Textbook pages: Chapter 12 |
Key Terms:
1. stoichiometry
2. mole-mole problems
3. mass-mass problems
4. mass-volume problems
5. volume-volume problems
|Directions: Use this information as a general reference tool to guide you through this unit |
|By the conclusion of this unit, you should know the following: |
|Quantitative relationships exist in all chemical reactions. |
|The amount of reactants directly influences (limits) the amount of product formed. |
|Thermochemical equations show energy changes that accompany chemical reactions. |
|By the conclusion of this unit, you should be able to do the following: |
|Use quantitative relationships to predict amounts of products formed. |
|Define stoichiometry and describe its importance |
|Relate stoichiometry to balanced chemical equations |
|Identify and solve different types of stoichiometry problems |
|Calculate the amount of product formed in a chemical reaction when reactants are present in nonstoichiometric proportions |
|Be able to identify and write balanced chemical equations to solve stoichiometry problems |
|Calculate percent yield |
|Use the mass of a reactant to determine how much heat will be gained or lost. |
6. particle –particle problems
7. expected yield
8. actual yield
9. percent yield
[pic]
Review/practice conversions: Use dimensional analysis to make the mole conversions below. Show all work. Label everything!!!!!
1. First, determine the molar mass of each substance below:
|SUBSTANCE |MOLAR MASS |
|AlCl3 | |
| |26.98 + (3 x 35.45) = 133.33 g |
|Cl2 | |
| |35.45 x 2 = 70.9 g |
|Ca3(PO4)2 | |
| |(40.08 x 3) + ( 30.97 x 2) + (16.00 x 8) = 310.18 g |
1. 10.7g of aluminum chloride to formula units
10.7g AlCl3 x 1 mol AlCl3 x 6.02 x 1023 formula units AlCl3
133.33 g AlCl3 1 mol AlCl3
2. 20.0g of chlorine gas to L at STP
20.0g Cl2 x 1 mol Cl2 x 22.4 L Cl2
70.9 g Cl2 1 mol Cl2
3. 4.45 x 1022 molecules of ammonia gas (NH3) to L at STP
4.45 x 1022 molecules NH3 x 1 mol NH3 x 22.4 L NH3
6.02 x 1023 Molecules NH3 1 mol NH3
I. MOLE to MOLE problems
Given the moles of one substance and asked to find the moles of another substance in a RXN
Stoichiometry Step-by-Step!
Ex. How many moles of O2 are needed to react with 0.52 moles of Mg?
Step 1 Balance the equation
2 Mg + O2 ( 2 MgO
Step 2 Write the given mole quantity (start your bridge)
Step 3 Write the mole ratio (moles of what you want / moles of what you have)
▪ This comes from the coefficients in the balanced equation
When nitrogen and hydrogen gas are heated under the correct conditions, ammonia gas (NH3) is formed.
a. Rxn MUST be BALANCED: 1 N2 + 3 H2 ( 2 NH3
b. How many moles of nitrogen react with three moles of hydrogen?
3 mol H2 1 mol N2
3 mol H2
c. How many moles of nitrogen react with six moles of hydrogen?
6 mol H2 1 mol N2
3 mol H2
d. How many moles of ammonia would be formed if 6 moles of hydrogen react with plenty of nitrogen?
6 mol H2 2 mol NH3
3 mol H2
e. How many moles of ammonia would be formed if 2.54 moles of nitrogen react with plenty of hydrogen?
2.54 mol N2 2 mol NH3
1 mol N2
f. How many moles of ammonia could be formed if 3.50 moles of hydrogen react with excess nitrogen?
3.50 mol H2 2 mol NH3
3 mol H2
g. How many moles of nitrogen are needed to react with 6.9 moles of hydrogen?
6.9 mol H2 1 mol N2
3 mol H2
More Practice: Mole Ratio Practice
1. Balance the equation: ____ N2 +__3__H2(_2___NH3
How many moles of hydrogen are needed to completely react with two moles of nitrogen?
2 mol N2 3 mol H2
1 mol N2
2. Balance the equation: __2___KClO3(___2__KCl +___3__O2
How many moles of oxygen are produced by decomposition of six moles of potassium
chlorate?
6 mol KClO3 3 mol O2
2 mol KClO3
3. Balance the equation: _____Zn +___2__HCl(_____ZnCl2 + _____H2
How many moles of hydrogen are produced from the reaction of three moles of zinc with an
excess of hydrochloric acid?
3 mol Zn 1 mol H2
1 mol Zn
4. Balancethe equation: ____C3H8 +__5__O2(__3__CO2 + ___4__H2O
How many moles of oxygen are necessary to react completely with four moles of propane
(C3H8)?
4 mol C3H8 5 mol O2
1 molC3H8
5. Balance the equation: ______K3PO4 +_____Al(NO3)3(__3__KNO3 + ____AlPO4
How many moles of potassium nitrate are produced when two moles of potassium phosphate react with two moles of aluminum nitrate?
2 mol K3PO4 3mol KNO3
1 mol K3PO4
II. MASS to MASS problems: Given the mass of one substance and asked to find the mass of another substance in a RXN
1. Given the balanced equation: 2 KClO3 ( 2 KCl + 3O2
How many grams of potassium chloride are produced if 25.0 g of potassium chlorate decompose?
25 mol KClO3 1 molKClO3 2 molKCl 74.55 g KCl
122.55 g KClO3 2 molKClO3 1 molKCl
III. VOLUME to VOLUME problems: Given the volume of one substance (gas at STP) and asked to find the volume of another substance (gas) in a RXN
1. Given the balanced equation: N2 + 3H2 ( 2NH3
a. At constant temperature and pressure, what volume of hydrogen is necessary to react with five liters of nitrogen to produce ammonia?
5 L N2 1 mol N2 3 mol H2 22.4 L H2
22.4 L N2 1 mol N2
IV. MASS to VOLUME problems: Converting from mass of one substance to volume of another in a RXN
1. Given the balanced equation: C3H8 + 5O2 ( 3CO2 + 4H2O
If 20 grams of oxygen are consumed in the above reaction, how many liters of carbon dioxide are produced?
20 g O2 x 1 mol x 3 mol CO2 x 22.4 L CO2
32 g O2 5 mol O2 1 mol CO2
MIXED PRACTICE
1. When iron is heated in pure oxygen, iron (III) oxide is formed. Write a balanced equation for the reaction below. What type of reaction is it? __synthesis___________
_______4Fe + 3 O2 2 Fe2O3________________________
a. What mass of iron must react with excess oxygen in order to form 4.81 moles of iron(III) oxide?
4.81 mol Fe2O3 4 mol Fe 55.8 g Fe
2 mol Fe2O3 1 mol Fe
b. What mass of iron is needed to react with 40.0 g of oxygen?
40.0 g O2 1 mol O2 4 mol Fe 55.8 g Fe
32.0 g O2 3 mol O2 1 mol Fe
c. What mass of iron(III) oxide can be formed from the reaction of 10.2 g of iron with excess oxygen?
10.2 g Fe1 mol Fe2 mol Fe2O3 159.6 g Fe2O3
55.85 g Fe4 mol Fe 1 mol Fe2O3
d. What mass of oxygen is needed to react with 12.7 g of iron?
12.7 g Fe 1 mol Fe 3 mol O2 32.0 g O2
55.85 g Fe 4 mol Fe 1 mol O2
e. Whatmass of iron(III) oxide will be formed if 10.0 L of oxygen at STP react with excess iron?
10 L O2 1 mol O2 2 mol Fe2O3 159.68 g Fe2O3
22.4 L O2 3 mol O2 1 mol Fe2O3
2. Barium hydroxide reacts with hydrochloric acid to form barium chloride and water. Write a balanced equation for the reaction below. What type is it? _double displacement___
_________Ba(OH)2 + 2HCl (BaCl2+ 2H2O___________________________
a. Whatmass of barium chloride will form if 14.0 g of barium hydroxide reacts with excess hydrochloric acid?
14.0 g Ba(OH)2 1 molBa(OH)2 1 mol BaCl2 208.3 g BaCl2
171.3Ba(OH)2 1 molBa(OH)2 1 molBaCl2
b. How many grams of hydrochloric acid are needed to react with 15.0 g of barium hydroxide?
15.0 gBa(OH)2 1 molBa(OH)2 2 molHCl 36.5 g HCl
171.3Ba(OH)2 1 molBa(OH)2 1 molHCl
c. Whatmass of barium chloride will form if 5.98 g of hydrochloric acid react with excess barium hydroxide?
5.98 g HCl 1molHCl 1 mol BaCl2 208.3 g BaCl2
36.5 g HCl 2 molHCl 1 molBaCl2
d. How many molecules of water are formed by the reaction of 10.8 g of barium hydroxide with excess hydrochloric acid?
10.8 gBa(OH)2 1 molBa(OH)2 2 mol H2O 6.02 x 1023molc. H2O
171.3 g Ba(OH)2 1 molBa(OH)2 1 mol H2O
LIMITING REACTANTS
LIMITING REACTANT: Present in the smallest stoichiometric amount;
Gets used up in the reaction(in this case, the H2);
determines the amount of product
EXCESS REACTANT: Not used up (left over);
added to ensure that the other reactant is completely used up; cheaper & easier to recycle
1. Balance the reaction below:
_4__Al + _3__O2 ( _2__Al2O3
2. 4.0 moles of aluminum are placed in a container with 4.0 moles of oxygen. How many moles of aluminum oxide should form?
There is enough aluminum to make _____________ moles of aluminum oxide.
4 mol Al x 2 mol Al2O3 = 2 mol Al2O3
4 mol Al
There is enough oxygen to make ________________ moles of aluminum oxide.
4 mol O2 x 2 mol Al2O3 = 2.67 mol Al2O3
3 mol O2
______2____________ moles of aluminum oxide will form.
The limiting reactant is __aluminum______. The excess reactant is ____oxygen________.
3. Predict the mass of aluminum oxide that will form if 20.0 g of aluminum react with 15.0 L of oxygen gas at STP.
There is enough aluminum to make ________________ g of aluminum oxide.
20 g Al x 1 mol Al x 2 mol Al2O3 x 102 g Al2O3 = 37.8 g Al2O3
27.0 g Al 4 mol Al 1 mol Al2O3
There is enough oxygen to make ________________ g of aluminum oxide
15 L O2 x 1 mol O2 x 2 mol Al2O3 x 102 g Al2O3 = 45.5 g Al2O3
22.4 L O2 3 mol O2 1 mol Al2O3
_______37.8________ g of aluminum oxide will form.
The limiting reactant is __aluminum______. The excess reactant is ____oxygen________.
1. Fluorine gas is bubbled through a solution of potassium iodide. The products of the reaction are potassium fluoride and iodine. Write a balanced equation for the reaction below.
F2 + 2 KI ( 2 KF + I2
What type of reaction is this? _single replacement___
12.6 g of fluorine is bubbled through a solution containing 20.15 g of potassium iodide. What mass of potassium fluoride should form?
12.6 g F2 x 1 mol F2 x 1 mol KF x 58.1 g KF = 9.63 g KF
38.0 g F2 2 mol F2 1 mol KF
20.15 g KI x 1 mol KI x 1 mol KF x 58.1 g KF = 7.05 g KF
166.0 g KI 1 mol KI 1 mol KF
Mass of KF that will form is 7.05
The limiting reactant is __potassium iodide__. The excess reactant is ___fluorine______.
SAMPLE PROBLEM: FINDING THE MASS OF EXCESS REACTANT
What mass of copper(II) iodide will be formed if 35.0g of copper are placed in a solution containing 90.0g of silver iodide?
a. Balanced Reaction: ___ Cu + 2 AgI ( CuI2 + 2 Ag __________________
b. Find the expected yield if copper is the limiting reactant:
35.0g Cu 1 mol Cu 1 mol CuI2 317.3g CuI2 = 174.9g CuI2
63.5g 1 mol Cu 1 mol CuI2
c. Find the expected yield if silver iodide is the limiting reactant:
90.0g AgI 1 mol AgI 1 mol CuI2 317.3g CuI2 = 60.8g CuI2
234.8g 2 mol AgI 1 mol CuI2
d. The limiting reactant is ____AgI____________. The excess reactant is ____Cu______.
e. Use the limiting reactant to determine how much of the excess reactant does react.
90.0g AgI 1 mol AgI 1 mol Cu 63.5g = 12.2g Cu reacted
234.8g 2 mol AgI 1mol CuI2
f. Subtract the amount that reacts from the amount you started with to find the mass remaining.
35.0g Cu– 12.2g Cu = 22.8g Cu remain
FINDING THE MASS OF EXCESS REACTANT
The next step in the limiting reactant process is determining the amount of excess reactant remaining following the reaction. There is a sample problem on the previous page. Follow the steps of the sample problem if you get lost!
Try the problem below:
1. What mass of carbon dioxide will be formed if 50.0g of propane gas are burned in 40L of pure oxygen at STP?
a. Balanced reaction: _C3H8 + 5 O2 ( 3 CO2 + 4 H2O____________________
b. Find the expected yield of carbon dioxide if propane is the limiting reactant:
50 g C3H8 x 1 mol C3H8 x 3 mol CO2 x 44.01 g CO2 = 149.73 g CO2
44.09 g C3H8 1 mol C3H8 1 mol CO2
c. Find the expected yield of carbon dioxide if oxygen is the limiting reactant:
40 L O2 x 1 mol O2 x 3 mol CO2 x 44.01 g CO2 = 47.15 g CO2
22.4 L O2 5 mol O2 1 mol CO2
d. The limiting reactant is ___O2_______. The excess reactant is ______C3H8_________.
e. Use the limiting reactant to determine how much of the excess reactant does react.
40 L O2 x 1 mol O2 x 1 mol C3H8 x 44.09 g C3H8 = 15.75 g C3H8
22.4 L O2 5 mol O2 1 mol C3H8
f. Subtract the amount that reacts from the amount you started with to find the mass of propane gas remaining.
50 – 15.75 = 34.25 g C3H8 remains
Percent Yield (How well did you do in the lab?)
• If you calculated a 3% error in a lab, then you should have a 97% yield.
• If you calculated a 10% error in a lab, then you should have a 90% yield.
Percent Yield: a comparison of how much product you produced in the lab and what you theoretically should have made according to your calculations.
1. A student burns 20.0L of propane gas in excess oxygen at STP. Determine the volume of carbon dioxide that should form in the reaction.
__1__C3H8 + __5__O2 ( __3__CO2 + __4__H2O
The reaction only produces 48.0 L of carbon dioxide. What is the percent yield?
20 L C3H8 x 1 mol C3H8 x 3 mol CO2 x 22.4 L CO2 = 60.0 L CO2
22.4 L C3H8 1 mol C3H8 1 mol CO2
What is the percent error? (100 – 80) = 20%
2. Sodium chlorate decomposes to produce sodium chloride and oxygen. Write and balance the reaction. The determine the mass of sodium chloride should form if 150g of sodium chlorate decomposes?
Reaction: 2 NaClO3 ( 2 NaCl + 3 O2
150 g NaClO3 x 1 mol NaClO3 x 2 mol NaCl x 58.5 g NaCl = 82.4 g NaCl
106.5 g NaClO3 2 mol NaClO3 1 mol NaCl
The reaction above is carried out in the lab, and 55 g of sodium chloride is collected.
What is the percent yield?
(55 ÷ 82.4) x 100% = 66.7%
Determine the percent error.
(100 – 66.7) = 33.3%
EXTRA NOTES
-----------------------
1 mole = 6.02 x 1023 molecules (covalent)
1 mole = 6.02 x 1023 formula units (ionic) HOW MANY PARTICLES
1 mole = 6.02 x 1023 atoms (monoatomic element)
1 mole = molar mass (grams) - HOW HEAVY
1 mole = 22.4L for a gas at STP – HOW MUCH SPACE
4.83 x1022formula units
6.32 L
1.66 L
Stoichiometry: mass relationships between substances in a chemical reaction
based on the mole ratio; Comparing chemical quantities to convert one element or compound to another.
Stoichiometric quantities - chemicals are usually mixed in exact amounts so that all the reactants will run out
Ex. H2 reacts with N2 to produce NH3.
If 33 L of H2 react, how many grams of NH3 do we produce?
Liter of H2 ( moles of H2 ( moles of NH3 ( grams of of NH3
2 mol N2
4 mol NH3
5.08 mol NH3
2.33 mol NH3
2.3 mol N2
6 mol H2
9 mol O2
3 mol H2
20.0 mol O2
6 mol KNO3
15.21 g KCl
15 L N2
8.4 L CO2
536.80 g Fe
93.07 g O2
14.58 gFe2O3
5.46 g O2
47.52 g Fe2O3
17.02 g BaCl2
6.39 g HCl
17.06 g BaCl2
7.59 x 1022molc. H2O
What you actually produced in lab
What stoichiometry predicts you will produce. (from calculation-theoretically)
................
................
In order to avoid copyright disputes, this page is only a partial summary.
To fulfill the demand for quickly locating and searching documents.
It is intelligent file search solution for home and business.
Related download
- practice test ch 3 stoichiometry name per
- stoichiometry calculations with chemical formulas and
- moles and stoichiometry practice problems from chapter 3
- single replacement reaction stoichiometry and percent yield
- chapter 10 chemical calculations and chemical equations
- percent yield and limiting reagents oak park usd
- chapter 11 stoichiometry
- chapter 3 stoichiometry
- stoichiometry ii limiting reactants and percent
- percent yield worksheet weebly
Related searches
- chapter 11 psychology answers
- philosophy 101 chapter 11 quizlet
- developmental psychology chapter 11 quizlet
- chapter 11 psychology quizlet answers
- psychology chapter 11 quiz quizlet
- chapter 11 personality psychology quizlet
- chapter 11 management quizlet
- 2 corinthians chapter 11 explained
- 2 corinthians chapter 11 kjv
- chapter 11 lifespan development quizlet
- the outsiders chapter 11 12
- chapter 11 and pension plans