Monday, Feb. 3rd: “A” Day
Tuesday, Feb. 4th: “B” Day
Agenda
Homework Questions/Problems
Sec. 12.3 Quiz
Lab Write-up: “Stoichiometry: Mass-Volume”
Mini-lab: “How Much Gas is in a Bottle of Pop?”
Homework: “Chemistry Gas Law Practice” WS
Chapter 12 Test/Concept Review Due:
“A” day: Tuesday, Feb. 11th
“B” day: Wednesday, Feb. 12th
Homework Questions
Practice pg. 442: #1-3
Sec. 12.3 review: pg. 442: #1-12
Additional Practice #2
Methane has a volume of 0.65 L when under
100 kPa of pressure at a temperature of 305 K.
Using the balanced equation below, find the mass
of oxygen that is needed to use up all of the
methane.
CH4 + 2 O2 CO2 + 2 H2O
Use PV = nRT to find moles of methane
(100 kPa) (0.65 L) = n (8.314) (305 K)
n = .026 mol methane
Use stoichiometry and molar mass to find mass of
oxygen needed
1.66 g O2
Sec 12.3 Quiz
“Molecular Composition of Gases”
You may use your book and your notes to
complete the quiz on your own…
May the force be
with you!
Lab: “Stoichiometry: Mass-Volume”
Discussion
A common way of collecting gaseous products is
by water displacement.
The reactants are placed in a closed reaction
vessel with a gas delivery tube attached.
The delivery tube passes through a pneumatic
trough filled with water and under an inverted
gas collection vessel that is filled with water.
As the reaction proceeds, the gas leaves the
reaction vessel and enters the collection vessel
through the gas delivery tube, displacing the
water.
Lab: “Stoichiometry: Mass-Volume”
Discussion
The volume of gas produced is equal to the
volume of water displaced in the gas collection
vessel.
Since the gas is collected through water, the gas
product is considered to be “wet” and this must
be accounted for in calculations.
Conditions in our lab must also be converted to
STP conditions to find the volume of dry gas
produced at STP.
Lab:
“Stoichiometry: Mass-Volume”
Purpose
In this lab, you will be producing, capturing, and
measuring the amount of CO2 gas produced by the
decomposition of lead carbonate and comparing
that to the theoretical yield using the following
reaction:
Δ
(PbCO3)2∙ Pb(OH)2 (s)
3 PbO(s) + 2 CO2 (g) + H20 (g)
Lab:
“Stoichiometry: Mass-Volume”
Hypothesis
Based on the purpose of the lab, come up
with a hypothesis.
Lab:
“Stoichiometry: Mass-Volume”
Changes to Materials List
Add lead carbonate. (PbCO3)2 · Pb(OH)2
Cross out the size of the test tube (18 X 150 mm)
Change thermometer to temperature probe.
Cross out the barometer – I will get the
atmospheric pressure reading for that day online.
Lab
“Stoichiometry: Mass-Volume”
Procedure Discussion
Prepare the data table as instructed before step #1
in procedure today. Include UNITS!
Lab: “Stoichiometry: Mass-Volume”
Lab Write-up
Read through the rest of the lab and complete the
write-up.
Don’t forget to leave room for your reflection
statement.
Be sure to update your table of contents.
 When you finish, pick up the “mini-lab” and read
through the procedure…
Mini-Lab: “How Much Gas is in a
Bottle of Pop?”
I thought this would be a fun lab as well as good
practice for the upcoming stoichiometry lab.
You will use the same gas collecting procedure for
this mini-lab as you will in the stoich lab.
Predict how much CO2 you think is in a
bottle of pop.
Mini-Lab: “How Much Gas is in a
Bottle of Pop?”
600 mL of hot tap water works well in the beaker.
You can use a hot plate to gently heat the water
in the beaker to speed up the release of CO2.
Have Fun!