AP Chemistry Day 21a focuses on stoichiometry and precipitation reactions, essential topics for high school chemistry students. It includes detailed examples of chemical equations involving acids, bases, and precipitates, providing a hands-on approach to understanding these concepts. Students will learn to write complete chemical equations and calculate moles and masses of precipitates formed in various reactions. This resource is ideal for AP Chemistry students preparing for exams and seeking to enhance their understanding of stoichiometry. Key topics include precipitation reactions, limiting reactants, and mass calculations.

Key Points

  • Explains precipitation reactions with complete chemical equations.
  • Calculates moles and masses of precipitates formed in reactions.
  • Covers stoichiometry principles relevant to AP Chemistry curriculum.
  • Includes examples of acid-base reactions and their products.
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AP CHEMISTRY
TOPIC 2: STOICHIOMETRY, REVIEW PART II Day 21:
Stoichiometry:
Precipitation Reactions
Acids and Bases
1) Write the COMPLETE EQUATION, if there is no reaction, write N.R.
a) A hydrochloric acid solution (an acid) reacts with aqueous lead(II) chlorate solution (NOT a base).
_2_ HCl
(aq)
+ ___ Pb(ClO
3
)
2
(aq)
_2_ HClO
3
(aq)
+ PbCl
2
(s)
b) An aqueous potassium sulfide solution reacts with aqueous bismuth(III) acetate solution.
_3_ K
2
S
(aq)
+ _2_ Bi(C
2
H
3
O
2
)
3
(aq)
_6_ KC
2
H
3
O
2
(aq)
+ ___ Bi
2
S
3
(s)
c) An aqueous potassium hydroxide solution reacts with aqueous nitric acid solution.
___ KOH
(aq)
+ ___ HNO
3
(aq)
___ HOH
(l)
+ ___ KNO
3
(aq)
d) An aqueous calcium hydroxide solution reacts with aqueous copper(II) chloride solution.
___ Ca(OH)
2 (aq)
+ ___ CuCl
2
(aq)
___ CaCl
2
(aq)
+ ___ Cu(OH)
2
(s)
2) Calculate the number of moles of the precipitate formed when 200.5 grams of barium nitrate (which is dissolved in enough
water so that the final volume of the solution is 2.5 liters) is mixed with a sodium phosphate solution (which is in excess).
SHOW ALL WORK
_3_ Ba(NO
3
)
2 (aq)
+ _2_ Na
3
PO
4
(aq)
_6_ NaNO
3
(l)
+ ___ Ba
3
(
PO
4
)
2
(s)
3 2 3 2 3 4
34
32
200.5 ( ) 1 ( ) 1
0.26
261.344 3 ( )
g Ba NO mol Ba NO mol Ba PO
mol Ba PO
g mol Ba NO
___ PbCl
2
(s)
___ Bi
2
S
3
(s)
___ Cu(OH)
2
(s)
___ Ba
3
(
PO
4
)
2
(s)
3) Calculate the mass of the precipitate that is formed when 620 mL of a 2.35 M calcium chloride solution is added to 375 mL of a
3.33 M copper(II) sulfate solution. SHOW ALL WORK
___ CaCl
2
(aq)
+ ___ CuSO
4
(aq)
___ CuCl
2
(aq)
+ ___ CaSO
4
(s)
42
2
42
375 1 3.33 1 1000
531
1000 1 2.35 1
mL L mol CuSO mol CaCl mL
L
mL CaCl
mL L mol CuSO mol CaCl L
CuSO
4
is the Limiting Reactant
44
4
44
375 1 3.33 1 136.14
170
1000 1 1
mL L mol CuSO mol CaSO g
g CaSO
mL L mol CuSO mol CaSO
4) What volume of a 4.50 M silver nitrate solution will react completely with 84.0 mL of a 4.53 M hydrochloric solution?
___ AgNO
3
(aq)
+ ___ HCl
(aq)
___ HNO
3
(aq)
+ ___ AgCl
(s)
84.0 1 4.53 1
0.0846
1000 1 4.5
mL HCl L mol HCl mol AgCl
L
L AgCl
mL L mol HCl mol AgCl
OR 84.6 mL
5) Calculate the volume (in milliliters), of the water formed when 300. mL of a 2.58 M sulfuric acid solution is mixed with 400.
mL of a 2.30 M sodium hydroxide solution. SHOW ALL WORK
___ H
2
SO
4
(aq)
+ _2_ NaOH
(aq)
_2_ HOH
(l)
+ ___ Na
2
SO
4
(aq)
24
24
24
400. 1 2.30 1 1000
178
1000 2 2.58 1
mL L mol NaOH mol H SO mL
L
mL H SO
mL L mol NaOH mol H SO L
NaOH is the Limiting Reactant
___ CaSO
4
(s)
___ AgCl
(s)
6) A student dissolves 525 grams of potassium oxide in enough distilled water so that the final volume is 3.55 liters in a
volumetric flask labeled “A”. Then in a different flask, she dissolves 623.25 grams of aluminum nitrate in enough
distilled water so that the final volume is 5.66 liters in a volumetric flask labeled “B”. She then mixes the two solutions
together. What is the mass, in grams, of the precipitate formed? SHOW ALL WORK
_3_ K
2
O
(aq)
+ _2_ Al(NO
3
)
3
(aq)
_6_ KNO
3
(l)
+ ___ Al
2
O
3
(s)
Al(NO
3
)
3
is the Limiting Reactant
_
33
3 3 2 3
23
3 3 2 3
623.25 ( )
1 ( ) 1
101.96
149
213.001 2 ( ) 1
g Al NO
mol Al NO mol Al O
g
g Al O
g mol Al NO mol Al O
7) Below are the products from “MANY different reactions”, circle those that would be not soluble in solution.
CaSO
4
Pb(C
2
H
3
O
2
)
2
(NH
4
)
2
CrO
4
Sr(OH)
2
Zn
3
(PO
4
)
2
Na
2
O
(NH
4
)
2
O
CuSO
4
Ca(ClO
3
)
2
Cs
3
PO
4
BaS
Ti
2
(CO
3
)
3
AgNO
3
Ni(OH)
3
MgCrO
4
CoI
3
AuCl
3
MgCO
3
LiOH
Pb(ClO
3
)
2
Mg(OH)
2
Au(ClO
3
)
3
Cr(C
2
H
3
O
2
)
3
BaSO
4
Mn
2
O
3
CuCl
2
FeCl
3
HgO
K
2
CO
3
AgBr
RbOH
NH
4
NO
3
___ Al
2
O
3
(s)
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FAQs

What are the key concepts covered in AP Chemistry Day 21a?
AP Chemistry Day 21a covers essential concepts in stoichiometry and precipitation reactions. Students learn to write complete chemical equations for various reactions, including those involving acids and bases. The document emphasizes calculating moles and masses of precipitates, which is crucial for understanding reaction yields. Additionally, it discusses limiting reactants and provides practical examples to reinforce these concepts.

How do you calculate the mass of a precipitate formed in a reaction?
To calculate the mass of a precipitate formed, you first need to determine the limiting reactant by calculating the moles of each reactant involved in the reaction. Once the limiting reactant is identified, you can use stoichiometric relationships from the balanced chemical equation to find the moles of the precipitate produced. Finally, multiply the moles of the precipitate by its molar mass to obtain the mass in grams.

What is the significance of limiting reactants in chemical reactions?
Limiting reactants are crucial in chemical reactions because they determine the maximum amount of product that can be formed. In a reaction, one reactant will be consumed first, limiting the extent of the reaction. Understanding which reactant is limiting helps chemists predict yields and optimize reaction conditions. This concept is fundamental in stoichiometry and is emphasized in AP Chemistry.

What types of reactions are included in the stoichiometry section?
The stoichiometry section includes various types of reactions, particularly precipitation reactions, acid-base reactions, and their respective products. Students learn to identify and write balanced equations for these reactions, which is essential for understanding chemical behavior. The document provides practical examples that illustrate how to apply stoichiometric principles in real-world scenarios.

How does AP Chemistry Day 21a prepare students for exams?
AP Chemistry Day 21a prepares students for exams by providing a comprehensive overview of stoichiometry and precipitation reactions, which are key topics in the AP Chemistry curriculum. The document includes practice problems, detailed explanations, and examples that reinforce students' understanding. By mastering these concepts, students enhance their problem-solving skills and are better equipped to tackle exam questions related to chemical reactions and stoichiometry.