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Name
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Per.
Avogadro Goes to Court
First read the provided account of "Avogadro Goes to Court."
Now it's your turn...
Determine the cost of one aluminum atom in dollars (3 SF), given the following information:
1. A roll of Reynolds aluminum foil has an area of 150. ft2.
2. A roll of this size costs $5.98 at Walmart.com
and the following materials (you do not necessarily need to use all of these):
1. A square of aluminum foil, 8"x 8"
2. More aluminum foil as needed
3. graduated cylinder
4. metric ruler
5. digital balance, 0.01 g
6. scissors
7. calculator
Use whichever experimental/problem-solving techniques you feel will be useful. Record all
the measurements you make in a clear manner, and show all work for any calculations that
you perform. You may write on this sheet. Good luck!
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Name
Per
Avogadro Goes to Court
First read the provided account of "Avogadro Goes to Court."
Now it's your turn...
Determine the cost of one aluminum atom in dollars (3 SF), given the following information:
1. A roll of Reynolds aluminum foil has an area of 150.ft2.
2. A roll of this size costs $5.98 at Walmart.com
and the following materials (you do not necessarily need to use all of these):
1. A square of aluminum foil, 8"x 8"
2. More aluminum foil as needed
3. graduated cylinder
4. metric ruler
5. digital balance, 0.01 g
6. scissors
7. calculator
Use whichever experimental/problem-solving techniques you feel will be useful. Record all
the measurements you make in a clear manner, and show all work for any calculations that
you perform. You may write on this sheet. Good luck!
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59 ÿ 10
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LAB: Percentaqe of Suqar in Bubble Gum
Purpose
To determine the percentage of sugar in bubble gum.
Hypothesis
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/ ÿvilt
What is your prediction for the percentage of sugar in bubblt gum? V0ÿJ%
Materials
ÿÿ//
balance, bubble gum
Note: Chewed gum cannot be placed directly on the balance pan; it must be
wrapped in paper and the mass of the paper subtracted out.
1. Your teacher will give you one piece of bubble gum. Place the wrapped piece
of gum on the balance. Record the mass of the wrapper and unchewed gum.
2. Unwrap your piece of gum, and put the gum in your mouth. Do not throw the
wrapper away.
3. Place your empty gum wrapper on the balance. Record the mass of the
wrapper. Do not throw the wrapper away!
4. Chew your gum for 15 minutes.
5. After 15 minutes, place your gum back in its wrapper.
6. Place your wrapped, chewed gum on the balance. Record the mass.
7. Throw away the gum and wrapper.
Data
Mass (g)
Wrapper and unchewed gum
Wrapper only
4. g4
0,2-c4
Unchewed gum
Wrapper and chewed gum
Chewed gum
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TURN OVER FOR ANALYSIS QUESTIONS!
Analysis and Conclusions
,
,
What is the total mass of sugar that you removed by chewing?
Hint: Subtract chewed gum's mass from unchewed gum's mass
Calculate the percent error for the mass of sugar. Obtain the actual value for
the mass of sugar iÿene piece of gum from your teacher:
Actual value=i/L[ d / g Experimental value= ÿ" ÿ ÿ g
//ÿ
(use answer for # 1 as your exp. value)
% Error = I Actual value - Experimental value I x 100
Actual value
! 4 °20 eÿoÿ J
,
(a) What is the percentage of sugar in a piece of gum?
Hint." °i sugax = Mass of sugar (fi'om #i) x i00
ass of unche wed gum
loo = "TY, F" %
t
(b)How did this compare to your predicted value?
(c) What assumption aye we making when we calculate this percentage?
f-lint: Do you t]ÿ'nk you removed anything else besides sugar when you
chewed the gum?
co(#rÿ9 ÿ f(avo:in9, cfc. 0ÿ o(so ÿssÿrrÿ "Phÿ ÿ Mÿesf
4. Would a lot of saliva trapped in the chewed gum cause the percentage of
sugar to appear higher or lower than it really is? Why?
Hint: Think about which measurement in the data table would be hiÿher,
' and what would that do to the answer to #l above?
5. Assume that the sugar tÿ the gum is sucros'e, ClÿHÿ2On. Using the answer
from #1 above as a starting point, calculate the molecules of sugar that you
removed by chewing. This is a mole conversion problem! Go from grams to
molecules. It takes 2 steps.
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Name
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Per.
DETERMINING THE NUMBER OF MOLES AND MOLECULES USED UP IN A
BURNING CANDLE
Wax is a mixture of hydrocarbons. C25H52 can be used as a representative hydrocarbon in
the mixture. The burning of wax is shown below:
C25H52 + 38 02 ....... > 25 CO2 + 26 H20 + energy
PURPOSE: To bum candle wax and to determine the number of moles and molecules
that undergo combustion.
PROCEDURE
1. Record the mass of a tea light candle + metal container (line a of data table). Data
table is on the back of this sheet.
,
Light the candle you weighed and let it burn for 10 minutes. Do not play with the
wax because this affects your results. Keep track of exactly how long your candle
burns.
While you wait, work these mole conversion problem as a warmup."
A) Pennies have a thin coating of copper plated over zinc. A penny is 2.5 %
copper and 97.5 % zinc by mass. Given that the mass of a penny is 2.50 g, how
many atoms of copper are in the penny?
2.
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B) Which is worth more, 1.0
[tÿÿ./.
2Omÿÿs
70ÿ._.J
ole of pennies, or 3.0 x 10-
quarters?
4 ÿo
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2.- '¢
ÿg
x
J. wnen me ume is up, mow out theÿzanme and allOW the waX-to cool.
4. Record the exact number of minutes (Ex. 11.5 min) that your candle burned (line b
of data table).
5. Reweigh the burned candle + container and record the mass (line c of data table).
6. Complete line d of the data table. Do calculations and answer questions.
Name
Per.
Candle Lab Data and Calculations/Questions
DATA TABLE
a.
Mass (g) of candle + container (before burning)
b.
Exact time candle burned (minutes)
C.
Mass (g) of candle + container (after burning)
d.
Mass (g) of wax that was burned
IZ, ÿto 9
o.3o01
(to calculate: line a - line c )
CALCULATIONS
1. What is the molar mass of wax? (use C25H52 to represent wax)
2. How many moles of wax were burned during this lab?
3. How many molecules of wax-ÿere burned during this lab?
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4. How many atoms of hydrogcÿffwere in the burned
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5. How long would it take to burn 1.00 moleHcandle wax?
Hint: Use dimensional analysis! Start with 1.00 mole of wax for the given quantity. You will
need to create a conversion factor from information in your data table.
/ (o.o ÿdÿ 1ÿ______ÿ
QUESTIONS
1. What 2 reactants are used up as a candle burns? Refer to introduction.
2. What has happened to the atoms in these reactants?
3. How many atoms of carbon are now floating around the room as components of carbon dioxide
molecules?
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t.
DETERMINING THE NUMBER OF MOLES AND MOLECULES IN
YOUR NAME
Name
PeF.
PURPOSE: To determine the number of moles and molecules used up when you write your name with
a crayon•
The predominant substance in crayon wax is:
CH3(CH2)7CH=CH(CH2)7CO2C7H9
PROCEDURE:
1. Record the mass of a crayon to the nearest 0.01 g in the table below.
2. On the back side of this lab, write your full name VERY LARGE, and as fancy as you want.
3. Record the mass of your crayon after writing your name.
4. Complete line c of the data table. Do calculations.
Crayon Data and Calculations/Questions
DATA TABLE:
a.
Mass of crayon (before writing your name)
b•
Mass of crayon (after writing your name)
C.
Mass of crayon used to write your name
4. 9 9
O.o
(to calculate: line a - line b )
CALCULATIONS: (Show dimensional analysis in # 2 - 5 below)
1. What is the molar mass of CH3(CH2)7CH=CH(CH2)7CO2C7H99 774o gtÿ
0ÿ,
.g/tool
2. How many moles of wax were used to write your name?
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3. How many molecules of wax were used to write your name?
J
4. now many individual atomsÿrÿjnÿprAmszverto#39 / I .-7-----"ÿ'-ÿ'-ÿ'-ÿ7ÿt
.....
I .ÿ. ÿct .ÿ,Ozvÿ
ÿ
I
[/gOJÿ
]
5. Another student did this lab using chalk instead o°fÿa crayon. Tÿce .in chalk
is calcium carbonate. If she used 0.11 g of chalk to write her name,
a) How many formula units of calcium carbonate did she use to ÿ¢rite her name?
b) How many calcium ions did
she use9
•
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lOVeS
DETERMINING THE NUMBER OF MOLES AND ÿ01ÿMaLA
YOUR NAME
U_ÿtT5 IkJ
PURPOSE: To determine the number of moles and molecules used up when you write your name with chalk.
The predominant substance in chalk is:
calcium carbonate Cd4 CO3
PROCEDURE:
1. Record the mass of a piece of chalk to the nearest 0.01 g in the table below.
2. On the mini chalkboard/black paper, write your full name VERY LARGE, and as farley as you want.
3. Record the mass of your chalk after writing your name.
4. Complete line e of the data table. Do calculations.
Chalk Data and Caleulations/Questions
DATA TABLE:
a,
Mass of chalk (before writing your name)
b.
Mass of chalk (after writing your name)
C.
Mass of chalk used to write your name
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O, O(o¢
(to calculate: line a - line b )
CALCULATIONS: (Show dimensional analysis in # 2 - 4 below)
1. What is the molar mass of calcium carbonate? ._J_ÿ _0 O, O dÿ g/mol
2. How many moles of calcium carbonate were used to write your name?
100,0q5
3. How many formula units of calcium carbonate were used to write your name?
4. How many calcium ions are in your answer to #3 ? ÿ,Xl0aoÿrucmÿt )ÿ / ÿz+ÿ ÿ- ¢ÿ,z\hÿoa,+
5. Another student did this lab using a crayon instead of chalk. The predominant substance in a crayon is
CHa(CH2)TCH=CH(CH2)TCO2CTHg. If she used 0. i 1 g of crayon to write her name.
a. How many molecules of crayon wax did she use to write her name?
5ÿq,sq 3
b.
How many atoms did she use?
LL_Z° J

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