Stoichiometry 6
OCTOBER 29 & 30 2012
MS. BOON CHEMISTRY
Objective:
 Catalyst:
•I can analyze
 Today is the third and last day of
laboratory data,
identify sources of
error, and write a
well-reasoned lab
report.
•Agenda:
•Catalyst
•Lab Day 3
•Exit Slip Review
•Let’s write a lab
report!
our copper and silver nitrate
stoichiometry lab.
 If you could do this lab again, or
another one like it, what would
you add to the lab to make it
more interesting, informative, or
fun?
Warm Up – Lab Day 3
Before we measure the mass of our silver. Let’s watch
a video.
Focus Question: Describe what you see using
scientific vocabulary. (chemical reaction, singledisplacement, reactants, products)

http://www.youtube.com/watch?v=niy1-u3oI5E
Agenda
• Catalyst
• Lab Day 3 – Data Collection & Begin Calculations
• Exit Slip Review
• Let’s write a lab report!
Lab Day 3: Data Collection (7 minutes)
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The last step in the lab procedure is to measure the
mass of the filter paper with the silver.
Each lab group must assign one person to pick up
their materials and another person to read the
triple beam balance.
Record your results in the Day 2/3 data table
Begin the Day 3 Calculations while we wait for all
groups to finish.
Exit Slip 10.25&26 – Standard 3a, 3d, 3e, 3f
Balance the chemical reaction equation.
___Li + __O2  ___Li2O
What is the molar mass of Li?
1.
7 g/mol
1.
What is the molar mass of Li2O?
2.
7+7+16 = 30 g/mol
1.
What is the molar mass of O2?
3.
16 + 16 = 32 g/mol
1.
4.
What is the mole ratio of Li2O to Li in the balanced equation?
1.
2.
5.
2 mol Li2O
4 mol Li
What is the mole ratio of Li2O to O2 in the balanced equation?
1.
2.
2 mol Li2O
1 mol O2
6.
How many grams Li2O will be produced from 56 g Li?
7.
How many grams Li2O will be produced from 32 g O2?
8.
Identify the limiting reactant and the theoretical (calculated) yield of silver
Li2O in grams, when 56 g Li reacts with 32 g O2.
If the actual yield is 30 g Li2O, what is the percent yield?
9.
Exit Slip 10.25&26 – 3a, 3d, 3e, 3f Review
6. How many grams Li2O will be produced from 56 g Li?
7. How many grams Li2O will be produced from 32 g O2?
8. Identify the limiting reactant and the theoretical
(calculated) yield of silver Li2O in grams, when 56 g Li
reacts with 32 g O2.
9. If the actual yield is 30 g Li2O, what is the percent yield?
Let’s Write a Lab Report
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Lab Report Criteria: Overview
Length: 4 paragraphs + attach all data, calculations, and observations.
Time: We will work on this today in class. Due today.
Academic standards assessed:
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IE 1b – identifying sources of error
W 1.3 – writing a logical and reasoned explanation
Format Requirements:
Title Lab Report: Stoichiometry Lab - Copper and Silver Nitrate Reaction
Introduction Paragraph explains the concept behind the lab.
Procedure Paragraph explains the lab procedure.
Data Analysis Paragraph explains the data and calculations.
Conclusion Paragraph analyzes sources of error and presents next
steps.
Let’s Write a Lab Report
 Lab Report Criteria: Overview
 Title Lab Report: Stoichiometry Lab - Copper and Silver
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Nitrate Reaction
Introduction Paragraph explains the concept behind
the lab.
The first sentence should state the purpose of the lab.
Define terms (limiting reactant, excess reactant,
theoretical yield; actual yield; percent yield)
Write a descriptive explanation of the single replacement
reaction between copper and silver nitrate.
Let’s Write a Lab Report
 Lab Report Criteria: Overview
 Procedure Paragraph explains the lab procedure.
 Write at least 5 sentences explaining the specific
steps of the lab. (How did you set up the
experiment? What did you measure? What did you
do on each day? Did you do anything different than
the written procedure?)
Let’s Write a Lab Report
 Lab Report Criteria: Overview
 Data Analysis Paragraph explains the data and
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calculations
What was your theoretical yield and what
measurement did you use to calculate it?
What was your actual yield and what measurements
did you use to calculate it?
What was your percent yield and what
measurements did you use to calculate it?
Attach all calculations.
Let’s Write a Lab Report
 Lab Report Criteria: Overview
 Conclusion Paragraph analyzes sources of error
and presents next steps.
 Provide at least three sources of error that may have
affected your measurements.
 Why was your actual yield different than your
theoretical yield?
 If you were to do a lab like this again, what next steps
would you add?