Mass Relationships in Chemical Reactions PowerPoint

Report
C: 13 Dec. 2010
Objective: SWBAT peer edit a
classmate’s lab report.
 Do now: What was the most difficult lab
report section to write? Why?

Agenda
Do now
II. Review percent composition
III. Peer Editing How-to
IV. Peer Editing Work Time
V. Get back your own lab report
Homework: Hand in any missing work
and/or schedule an appointment to take
a missed test or quiz or re-quiz!!
Final lab report due next Monday!
I.
Final draft of lab report
Do you want more advice on improving
your lab report?
 Come for extra help today or tomorrow at
3:30 in 203!

Percent Composition
Percent of water in CuSO4∙5H2O
Peer editing
1.
2.
3.
Reach each section of the lab report and
circle the box on the rubric (p. 1) that best
describes the qualities of that section.
Do not give points!
While you read, fill in the chart on page 2
(what works well, suggestions for
improvement)
Give one specific praise or suggestion for
each box!!
Then…
Give a score 1, 2, or 3 for each statement
in part 3
 Give the top 3 things for the person to
focus on when revising.
 If they only fixed three things, what
should they be?!

For example
For the Data and Results part
What works well: Your descriptions of
your qualitative data are complete and
thoughtful!
Suggestions for Improvement: You
should explain what you are doing for
each step of your calculations.

Three Things…Example
1.
2.
3.
Write your procedure as paragraphs, not
a list.
Include a calculation for actual percent
composition for water in the hydrate.
Include one more error and how it
affected your results.
For the rest of the period….
Work quietly on your own.
 If you’re not sure how to score a section,
or what to write, you may quietly ask your
partner or me.
 Return the lab report and two page
handout to me.

Homework
Hand in any missing work and/or schedule
an appointment to take a missed test or
quiz or re-quiz!!
Final lab report due next Monday!
C: 14 Dec. 2010
Objective: SWBAT calculate mass
relationships in chemical reactions.
 Do now:

2KNO3(s)  2KNO2(s) + O2(g)
a. How many moles of KNO2 are produced
by the reaction of 2 moles of KNO3?
b. How many moles of oxygen gas are
produced by the reaction of 0.50 moles of
KNO3?
Agenda
Do now
II. Review mole relationships
III. Mass relationships!
IV. Hand back lab reports
Homework: Week 15 Homework #1
(PAGE 1-2!)
Lab report final draft Monday.
I.
Mass Relationships in Chemical
Reactions
Work along on your worksheet!
SWBAT calculate mass relationships in chemical reactions.
Reviewing Mole Relationships
2KNO3(s)  2KNO2(s) + O2(g)
1. How many moles of O2 are produced when 2
moles of KNO2 are produced?
2. How many moles of KNO3 are required to
produce 4 moles of KNO2?
3. How many moles of KNO3 are required to
produce 5 moles of O2?
4. How many moles of O2 are produced by the
reaction of 13.5 moles of KNO3?
SWBAT calculate mass relationships in chemical reactions.

What if, instead of moles, the problem
gives you grams of a reactant or product
and asks you to calculate grams of another
reactant or product?!
SWBAT calculate mass relationships in chemical reactions.
Reaction Stoichiometry
Calculating:
• The number of moles and grams of
reactants that combine
• The number of moles and grams of
products produced
You already know every part of reaction
stoichiometry.
The trick is putting these skills together into
one process.
SWBAT calculate mass relationships in chemical reactions.
Part I

First, review moles to moles stoichiometry
4Al(s) + 3O2(g) → 2Al2O3(s)
PART I: Use the equation above to solve the
following problems:
STEP 1: Write the given value, with a unit, over one
STEP 2: Write a blank conversion factor
STEP 3: Put your given unit and substance on the
bottom of your conversion factor and the units you
want to find on the top of your conversion factor
STEP 4: fill in the numbers in your conversion factor
using the equation
STEP 5: Multiply what’s on top, divide by what’s on
bottom. Write your final answer.

PART II: Now let’s say we wanted to know how
many grams would be produced/needed rather
than how many moles? What could we do to find
this?
To find grams from moles___________________
1.
Use your answer from STEP 5 as your new given,
put it over 1
2.
Write a blank conversion factor
3.
Put your given unit and substance on the bottom of
your conversion factor and the units you want to
find (grams) on the top of your conversion factor
4.
Fill in the numbers using the molar mass of that
substance
5.
Multiply what’s on top, divide by what’s on bottom.
Write your final answer.

PART III:
Now you have converted:
MOLES of A  MOLES of B  MASS of B
Using: ______________ Using: ______________
But in the lab, we usually need to measure our substances
in grams on both ends, so we need to be able to answer
questions like:
Example 1: How many grams of aluminum are needed to
produce 9 grams of aluminum oxide?
How could we solve this problem?
MASS of A  MOLES of A  MOLES of B  MASS of B
Using: _______Using: _________ Using: _________

1.
2.
Just like when doing 2 step conversions in
the past, to solve these multi-step
problems:
Make a _______________________
When in doubt on where to start, convert
to _______________
A: 14 Dec. 2010
Take Out Homework: Week 15
 Objective: SWBAT calculate mass
relationships in chemical equations.
 Do now:
4Al(s) + 3O2(g) → 2Al2O3(s)
a. How many moles of aluminum oxide will
be produced by the reaction of 25 moles of
aluminum?
b. How many grams of aluminum oxide is
that?

Agenda
Do now
II. Mass to mass conversions examples
III. Practice Problems
IV. Copper Cycle Pre-Lab
V. Hand back lab reports
Homework: Week 15 Homework finish #1, #2
(PAGES 3-4): Thurs.
Lab report final draft due Monday
Read Lab Handout Procedure, do pre-lab
questions and become an expert
I.
4Al(s) + 3O2(g) → 2Al2O3(s)

Example 1: How many grams of
aluminum are needed to produce 9 grams
of aluminum oxide?
SWBAT calculate mass relationships in chemical equations.
4Al(s) + 3O2(g) → 2Al2O3(s)

Example 2: How many grams of
aluminum oxide can be produced from 13
grams of aluminum?
SWBAT calculate mass relationships in chemical equations.
4Al(s) + 3O2(g) → 2Al2O3(s)

Example 3: How many grams of oxygen
gas are needed to react with 11 grams of
aluminum?
SWBAT calculate mass relationships in chemical equations.
C: Homework
Week 15 Homework #1 (PAGE 1-2)
 Lab report final draft: Mon.
 If you didn’t get your lab report
back, please come talk to me!
Come to extra help for…extra help!

SWBAT calculate mass relationships in chemical equations.
A: Homework
Week 15 Homework #1 (finish) #2 (PAGE
3-4!!): Thurs
 Lab report final draft: Mon.
 Read Lab Handout, do pre-lab questions,
and become the expert on your section:
due tomorrow
Come to extra help for…extra help!

SWBAT calculate mass relationships in chemical equations.
C: 15 Dec. 2010
Take Out Homework: Week 15
Homework p. 1-2
 Objective: SWBAT calculate mass
relationships in chemical reactions.
 Do now: Write and balance the equation:
Hydrogen gas reacts with chlorine gas to
produce a solution of hydrochloric acid.

Agenda
Do now
II. Homework solutions
III. A few more mass to mass calculation
problems
IV. Pre-lab discussion of safety
V.
Read procedure and become an expert
Homework: Week 15 #2 (PAGES 3-4): Mon.
Do pre-lab, including procedure questions: Fri.
Final lab report: Mon.
I.
H2(g) + Cl2(g)  2HCl(g)
1.
2.
3.
How many grams of hydrochloric acid are
produced when 3.50 grams of hydrogen is
reacted with excess chlorine gas?
excess: more than enough
How many grams of hydrogen gas are
required to produce 5.00 grams of
hydrochloric acid?
How many grams of chlorine gas reacts
exactly with 4.9 grams of hydrogen gas?
SWBAT calculate mass relationships in chemical reactions.
4Fe(s) + 3O2(g)  2Fe2O3(s)
1.
2.
3.
4.
How many grams of iron (III) oxide are
produced by the reaction of 1.00 grams of
iron in excess oxygen?
How many grams of oxygen are required to
react exactly with 5.00 grams of iron?
How many grams of oxygen are required to
produce 3.50 grams of iron(III) oxide?
How many grams of iron (III) oxide are
produced by the reaction of 0.50 grams of
oxygen with excess iron?
SWBAT calculate mass relationships in chemical reactions.
COPPER CYCLE LAB
Cu L8R!
Safety
This lab uses HIGH concentrations of
chemicals
 Chemicals could burn skin, clothing, and
eyes
 MUST wear goggles at all times in lab
 May take 1minute goggle breaks in the
hallway as needed (2 at a time)
 If you are not wearing your goggles in the
lab, I will ask you to go to the office until
you can behave safely.

Chemical burns
Safety



What does “behaving safely” look like?
Examples:
 Stay at lab station, don’t wander the room
 Be careful with glassware and chemicals
 Never squirt anyone or anything with any
chemical (INCLUDING WATER)
 Notify Ms. Boiteau of any spills/breakage
right away – clean thoroughly
MUST behave carefully and safely
 If you are not behaving safely, I will ask you to
go to the office until you can behave safely.
You are the experts!
Each group member will be an expert on
one section of the procedure
 This person is responsible for managing
that part of the procedure for the group
 Understanding what is going on
 Being the primary ‘doer’ during that
section – measuring chemicals, etc.
 Your group is counting on you!

For the rest of the period…
Do the pre-lab questions on the front
page.
2. Read the procedure.
3. For the section for which you are the
expert, complete the questions after
those procedure steps.
Due tomorrow!!
1.
Homework



Week 15 #2 (PAGES 3-4): Mon.
Do pre-lab, including procedure
questions: Fri.
Final lab report: Mon.

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