**CHM 2045C Module Six
Sample Exam **** Answers**

**Part
F Volume-Volume Stoichiometry
5 points**

In the Haber process, **nitrogen
N _{2}** and

Using ChemiCalc
to balance the equation.

**Step
#1 Write the balanced reaction**

** N _{2 }**

**Step
#2 Write the question in Dimensional Analysis format:**

**__ ?__ L N_{2} = 5.55
L NH_{3} **

**Step
#3 Setup the dimensional analysis problem.**

**Think
about the Road map of Stoichiometry:**

**It
is one step with a direct volume to volume unit factor similar to the mole
ratio. See (f) above. **

**See Section**** 10.6 of Chapter 10 as this
is the very problem from your textbook on page 264.**

** First answer is 11.1 L
NH _{3}**

**Second
Question: __ ?__ L H_{2} = 5.55
L NH_{3}**

**Second answer: 16.65 L H _{2}**

**Part
G Mass-Volume Stoichiometry 5 points**

Potassium chlorate is
used in the lab to make oxygen gas by the following (unbalanced) reaction:

** KClO**_{3}** ****à****
KCl
+ O**_{2}

How liters of
oxygen at STP may be made from reacting 1.226 grams of Potassium chlorate?

Step #1: Write and
Balance the Equation:

**2 KClO**_{3}** ****à**** 2 KCl +
3 O**_{2}

_{ }

**Step#2
Write**
the question in Dimensional Analysis format:

**__ ?__ L O_{2} = 1.226
g KClO_{3}**

**Step#3
Think**
about the Stoichiometry Road Map

**a.** Change **grams of KCLO _{3}
to**

**b.** Change **moles of KCLO _{3}** to

**c.** Change **moles of O _{2}** to

**Step #4 Setup** and Solve the Dimensional Analysis
Sequence:

**Your answer is 0.336 L O _{2 }**