# Study Buddy Unit II- Constant Velocity ```Study Buddy: Stoichiometry 1: Theoretical
Terms
Description
Diagram/Example
Stoichiometry
Reaction:
A + B  C
_________:
5g + 5g  ___
In the lab, 5g of each reactant were
used and the reaction yielded 8g of
C. (_______________)
Theoretical Yield
Actual Yield
Percent Yield
% Yield:
x 100% = _________
Representations:
1. For the reaction
a. Draw a particle diagram to represent the reaction
2HCl
+
Mg

H2
+
MgCl2
b. Circle the ratios below are invalid for this reaction, and explain why they are not correct.
2 moles HCl
1 atom Mg
1 mole Mg
1 molecule H
1 mole MgCl
1 molecule H
1) 1 mole H
2) 1 mole MgCl
3) 1 mole H 4) 1 atom Mg 2 5) 1 mole HCl 2 6) 1 mole MgCl2
2
2
2
2. a. Rank the amounts of oxygen gas (O2) in increasing order: 1.2x1024 molecules, 32g, 1.5 moles
least amount: ______________, ______________, ______________: most amount
b. Rank the number of particles in 100g of: NaCl, CaCO3, FeCl3, MnO2
least amount: _________, _________, _________, _________: most amount
3. When potassium chlorate is heated it decomposes into potassium chloride and oxygen
___KClO3(s)  ____KCl(s) + ____O2(g)
Students performed this reaction in class and obtained 85g of KCl.
a. How many grams of KCl should be produced from 165 grams of KClO3?
b. Circle the theoretical yield. How would a student know this is the theoretical yield?
c. Place a box around the actual yield. How would a student know this is the actual yield?
d. What is the percent yield of potassium chloride for this reaction?
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Study Buddy: Stoichiometry 2: Applications
Terms
Description
Diagram/Example
Excess =
Excess Reactant
Limiting =
Limiting Reactant
Representations:
1.
___ CH4(g) + ___ O2(g)  ___ CO2(g) + ___ H2O(l) + 891 kJ
a. When using natural gas (mostly methane) to cook, which reactant is limiting and why?
b. In a closed container, 100.g of methane and 100.g of oxygen gas are ignited by a spark.
Which reactant is limiting and how do you know?
c. Draw particles to represent this reaction in the containers.
Key:
spark
Reactants Before Reaction
Carbon
Hydrogen
Oxygen
Products After Reaction
d. How many liters of carbon dioxide can be produced?
e. How many grams of the excess reactant will be used in the combustion?
2. What can cause the percent yield for a reaction to be less than 100%, other than human error?
3. Draw particle diagrams to represent this reaction:
___ KI ( ) + ___ Pb(NO3)2 ( )  ___ PbI2 ( ) + ___ KNO3 ( )
Key:
K
I
Pb
NO3
3/17/15 SCIE_CHEM_STOICH1_MAT_STUDYBUDDYSE_AL