DCI 2.1 - Stoichiometry
An atom of R weighs 1 mass unit (mu),
G weighs 3 mass units (mu) and B
weighs 2 mass units (mu).
i) the mass of BG would be: ____mu
ii) the mass of RG would be: ____mu
Table II: Experiment #1.
Ex p. #1
Formula
REACTANTS
Reactant(1)
R
REACTANTS
Reactant(2)
BG
--->
PRODUCTS
Product(1)
RG
PRODUCTS
Product(2)
B
Initial Amount
4
4
0
0
Change Amount
-4
-4
+4
+4
Final Amount
0
0
4
4
Table III Exp #1
1mu
5mu
REACTANTS
Reactant(2)
BG
--->
4mu
2mu
Ex p. #1
Formula
REACTANTS
Reactant(1)
R
PRODUCTS
Product(1)
RG
PRODUCTS
Product(2)
B
Initial mass
4 mu
20 mu
0 mu
0 mu
Change in mass
-4 mu
-20 mu
+16 mu
+8 mu
Final mass
0
0
16 mu
8 mu
Table II: Exp #2
REACTANTS
Reactant(1)
REACTANTS
Reactant(2)
R
BG
Initial mass
4
Change in mass
Final mass
Ex p. #2
Formula
PRODUCTS
Product(1)
PRODUCTS
Product(2)
RG
B
2
0
0
-2
-2
+2
+2
2
0
2
2
4mu
2mu
--->
Complete Table III for Exp #2:
Table III: Exp #2.
1mu
5mu
REACTANTS
Reactant(1)
REACTANTS
Reactant(2)
R
BG
Initial mass
mu
Change in mass
Final mass
Ex p. #2
Formula
PRODUCTS
Product(1)
PRODUCTS
Product(2)
RG
B
mu
mu
mu
mu
mu
mu
mu
mu
mu
mu
mu
--->
Table II: Exp #2
REACTANTS
Reactant(1)
REACTANTS
Reactant(2)
R
BG
Initial mass
4
Change in mass
Final mass
Ex p. #2
Formula
PRODUCTS
Product(1)
PRODUCTS
Product(2)
RG
B
2
0
0
-2
-2
+2
+2
2
0
2
2
4mu
2mu
--->
Complete Table III for Exp #2:
Table III: Exp #2.
1mu
5mu
REACTANTS
Reactant(1)
REACTANTS
Reactant(2)
R
BG
Initial mass
4 mu
Change in mass
Final mass
Ex p. #2
Formula
PRODUCTS
Product(1)
PRODUCTS
Product(2)
RG
B
10 mu
0 mu
0 mu
-2 mu
-10 mu
+8 mu
+4 mu
2 mu
0 mu
8 mu
4 mu
--->
Table II: Exp #3
REACTANTS
Reactant(1)
REACTANTS
Reactant(2)
R
BG
Initial mass
2
Change in mass
Final mass
Ex p. #3
Formula
PRODUCTS
Product(1)
PRODUCTS
Product(2)
RG
B
4
0
0
-2
-2
+2
+2
0
2
2
2
4mu
2mu
--->
Complete Table III for Exp #3:
Table III: Exp #3.
1mu
5mu
REACTANTS
Reactant(1)
REACTANTS
Reactant(2)
R
BG
Initial mass
mu
Change in mass
Final mass
Ex p. #3
Formula
PRODUCTS
Product(1)
PRODUCTS
Product(2)
RG
B
mu
mu
mu
mu
mu
mu
mu
mu
mu
mu
mu
--->
Table II: Exp #3
REACTANTS
Reactant(1)
REACTANTS
Reactant(2)
R
BG
Initial mass
2
Change in mass
Final mass
Ex p. #3
Formula
PRODUCTS
Product(1)
PRODUCTS
Product(2)
RG
B
4
0
0
-2
-2
+2
+2
0
2
2
2
4mu
2mu
--->
Complete Table III for Exp #3:
Table III: Exp #3.
1mu
5mu
REACTANTS
Reactant(1)
REACTANTS
Reactant(2)
R
BG
Initial mass
2 mu
Change in mass
Final mass
Ex p. #3
Formula
PRODUCTS
Product(1)
PRODUCTS
Product(2)
RG
B
20 mu
0 mu
0 mu
-2 mu
-10 mu
+8 mu
+4 mu
0 mu
10 mu
8 mu
4 mu
--->
Compare the results of Tables II and
III.
What is the relationship between the amounts
of substances in each of the two tables?
How is the set of numbers for the initial
amounts related to the balanced chemical
equation?
Compare the results of Tables II and
III.
How is the set of numbers for the final
amounts related to the balanced chemical
equation?
How is the set of numbers for the change
amounts related to the balanced chemical
equation?
1. Consider the following chemical equation describing
the reaction between sulfur dioxide and oxygen.
2SO2 (g) + O2(g) → 2SO3(g)
Given the following container as
representing the final condition:
Which of the containers (-->) best
represents the initial conditions?
1. Consider the following chemical equation describing
the reaction between sulfur dioxide and oxygen.
2SO2 (g) + O2(g) → 2SO3(g)
Given the following container as
representing the final condition:
Which of the containers (-->) best
represents the initial conditions?
2. Which of the following changes can be described by
the balanced chemical equation,
A2(g) + 3B2(g) → 2AB3(g)
A) I only
B) II only
C) I and III
D) II and III
E) I, II and III
3. Which of the chemical equations best describes the reaction
represented by the containers below? Consider the container label
‘initial condition’ as the reactants before any reaction has
occurred, and the container labeled ‘final condition’ as the same
container after the reaction has reached completion.
A)
B)
C)
D)
E)
4A2(g) + 7B2(g) → 4AB3(g)
4A2(g) + 7B2(g) → 4AB3(g) + 1B2(g) + 2A2(g)
A2(g) + 3B2(g) → 2AB3(g)
4A2(g) + 6B2(g) → 4AB3(g)
A2(g) + B2(g) → AB3(g)
4. Consider the hypothetical reaction:
2G + R --> G2R
If G has a mass = 3 mu and R = 2 mu
What is in excess and what is the limiting
reagent if 6 mu of R and 6 mu of G are
mixed?
A. R is the excess reagent and G is the
limiting reagent:
B. G is the excess reagent and R is the
limiting reagent:
C. both R and G are excess reagents:
D. both R and G are limiting reagents