Transcript Summer Assignment

AP Chemistry Summer Assignment
Hello again…I feel like we were just talking to each other on that half sheet of paper!
Now we are about to start our summer work!
Don’t be discouraged, if you happen to notice there are 100 pages here.
Many of them are repetitious – I set up problems in a series of pages to show steps.
There are 7 lessons here. Take your time and spread them out.
Each lesson should take less than an hour.
In 2014, I taught AP chemistry for the first time, and made many assumptions
about what AP students would already know. I was wrong.
Significant digits and chemical formulas are two ‘prerequisite’ topics,
meaning you are supposed to know them from regular chemistry.
They are very important.
Most topics we learn this year have both topics embedded in the questions
and count towards your grade.
Do the best you can, complete the homework, email all 7 assignments or print them out.
There will be a quiz the 13th day of school. The assignments are due the 14th day of school.
Ch1.1 Chemical Foundations
Scientific Method – a systematic approach
to solving scientific problems
1. O
2. H
3. E
4. R
5. A
6. C
Ch1.1 Chemical Foundations
Scientific Method – a systematic approach
to solving scientific problems
1. Observation
2. Hypothesis
3. Experiment
4. Results
5. Analysis
6. Conclusions
Please keep this in mind as you perform laboratory
assignments this year.
Units of Measurement
We deal in measurements, not numbers!
All ‘numbers’ have a unit of measure that
is as important as the number!
Units of Measurement
We deal in measurements, not numbers!
All ‘numbers’ have a unit of measure that
is as important as the number!
For example, if I asked you to mass a penny
and you responded, “It’s 1.5.”
I might be confused. If you meant 1.5 pounds, that would be
an extremely heavy penny, especially if I have a piggy bank full of them!
You respond, “the penny masses at 1.5 grams.”
Now you can see how important units are to measurements.
Units of Measurement
We deal in measurements, not numbers!
All ‘numbers’ have a unit of measure that
is as important as the number!
What if I asked you to mass my piggy bank. It is an old plastic drinking bottle,
that holds five gallons of water. If it was full of pennies it might be hard to lift.
So you mass it, and the scale reads 50,000 grams.
If you worked at the bank and massed ALL the pennies in the vault,
they might mass at 1,000,000grams.
All the pennies in Apple Valley might mass at 1,000,000,000grams! IDK,
I’m just making this up…but you can see that maybe we need a different
unit of measure.
In the English system, you mass individual pennies in ounces,
then piggy banks in pounds, then all the pennies in tons.
What does the metric system do?
Units of Measurement
The metric system uses a system of prefixes.
Giga . . Mega . . Kilo Hecta Deka Basic deci centi milli . . micro . . nano . . pico
Units
G .. M .. K H D U d c m .. μ .. n .. p
Basic units:
meters, liters, grams, kelvins, seconds, moles, etc
Ex1)
3.5 mL = ______ L
Units of Measurement
The metric system uses a system of prefixes.
Giga . . Mega . . Kilo Hecta Deka Basic deci centi milli . . micro . . nano . . pico
Units
G .. M .. K H D U d c m .. μ .. n .. p
Look at the unit given.
Find the prefix on the chart.
Count the movement
to get to the desired unit.
Ex1)
3.5 mL = ______ L
Units of Measurement
The metric system uses a system of prefixes.
Giga . . Mega . . Kilo Hecta Deka Basic deci centi milli . . micro . . nano . . pico
Units
G .. M .. K H D U d c m .. μ .. n .. p
I moved the arrow 3 places
Ex1)
3.5 mL = ______ L
to the left.
So I will move the decimal 3 places to the left:
= 0.0035 L
Units of Measurement
The metric system uses a system of prefixes.
Giga . . Mega . . Kilo Hecta Deka Basic deci centi milli . . micro . . nano . . pico
Units
G .. M .. K H D U d c m .. μ .. n .. p
If you need to move the decimal
past milli, don’t forget to count
the dots as well.
Ex2)
1 mg = ______ μg
Units of Measurement
The metric system uses a system of prefixes.
Giga . . Mega . . Kilo Hecta Deka Basic deci centi milli . . micro . . nano . . pico
Units
G .. M .. K H D U d c m .. μ .. n .. p
If you need to move the decimal
Ex2)
1 mg = ______ μg
past milli, don’t forget to count
the dots as well.
So I will move the decimal 3 places to the right:
= 1000 μg
Units of Measurement
The metric system uses a system of prefixes.
Giga . . Mega . . Kilo Hecta Deka Basic deci centi milli . . micro . . nano . . pico
Units
G .. M .. K H D U d c m .. μ .. n .. p
Ex3)
1 pm = ______ m
Units of Measurement
The metric system uses a system of prefixes.
Giga . . Mega . . Kilo Hecta Deka Basic deci centi milli . . micro . . nano . . pico
Units
G .. M .. K H D U d c m .. μ .. n .. p
Ex3)
1 pm = 0.0000000000001 m
or
1 x 10-12 m
Using density as a way to learn about uncertainty:
Density is the first chemistry method
to discover an unknown substance.
mass
D
volume
Units :  g 3 or g 
 cm   ml 
Ex4) The density of an unknown metal is to be found experimentally.
One lab group masses a small cylinder of the unknown, using a digital scale,
and measures it to be 48.95g. They measure the volume by water displacement
in a 100mL graduated cylinder, and find it to be 6.27cm3.
The members of this lab group, who must be really into chemistry, go to one
student’s home and find a large iron cylinder in the garage. They mass it on
a metric bathroom scale and it masses 5kg. They measure the diameter
of the cylinder, using a tape measurer, to be 8cm, and length to be 10cm.
Find the density for each experiment.
Mass 1: _____ g
Vol 1: _____ cm3
Mass 2: _____ g
Vol 2: ______ cm3
Ex4) The density of an unknown metal is to be found experimentally.
One lab group masses a small cylinder of the unknown, using a digital scale,
and measures it to be 48.95g. They measure the volume by water displacement,
and find it to be 6.3cm3.
The members of this lab group, who must be really into chemistry, go to one
student’s home and find a large iron cylinder in the garage. They mass it on
a metric bathroom scale and it masses 5kg. They measure the diameter
of the cylinder to be 8cm, and length to be 10cm.
Find the density for each experiment.
Mass 1: 48.95 g
Vol 1: 6.3 cm3
D
7.87
48.95 g
6.3 cm
3
Mass 2: 5000 g
Vol 2: (πr2h) = π(4cm)2(10cm) = 503 cm3
 7.76984127 g
D
cm3
5000 g
503 cm
3
 9.947183943 g
cm3
Mass 1: 48.95 g
Vol 1: 6.3 cm3
D
48.95 g
6.3 cm
3
Mass 2: 5000 g
Vol 2: (πr2h) = π(4cm)2(10cm) = 503 cm3
 7.76984127 g
D
cm3
5000 g
503 cm
3
 9.947183943 g
cm3
It is obvious the bathroom scale lacks the precision of the digital scale.
It is worth looking up water displacement for volume measurements.
It is highly precise. Tape measurers are fairly accurate, but not that precise.
So…what I’m getting at is how do we show the precision of measurements
in our answers, and how do we measure and report error?
‘We deal in measurements, not numbers!
These measurements contain a certain amount of uncertainty.’
Significant digits
Look at the measurements, count the number of digits:
Mass 1: 48.95 g (4 sig digs)
Mass 2: 5000 g (1 sig dig)
Vol 1: 6.3 cm3 (2 sig digs)
Vol 2: 503 cm3 (3 sig digs)
Round answers to the same number of sig digs as the measurement with
the fewest sig digs:
D1 
D2 
48.95 g
 7.76984127 g
3
6.3 cm
5000 g
503 cm
3
cm3
 9.947183943 g
 7.8 g
cm3
cm3
 10 g
cm3
You may wonder why 5000g has only 1 sig dig. Hey, that’s the rules
you should have learned in regular chemistry…but I’ll be happy to explain them
when we are finally together. Otherwise, you can always You Tube it!
‘We deal in measurements, not numbers!
These measurements contain a certain amount of uncertainty.’
What about error reporting?
The actual value for the density of iron is 7.87g/cm3.
What is the percent error for each experiment?
| actual # - experiment al # |
% error 
 100 %
actual #
‘We deal in measurements, not numbers!
These measurements contain a certain amount of uncertainty.’
What about error reporting?
The actual value for the density of iron is 7.87g/cm3.
What is the percent error for each experiment?
| actual # - experiment al # |
% error 
100 %
actual #
| 7.87g - 7.8g |
Exp1 
100 %  0.89 %
7.87g
| 7.87g - 10g |
Exp2 
100 %  27 %  30 %
7.87g
Why isn’t the bottom answer (–)? Absolute value sign of course!
Why did you round to 30%? One sig dig of course!
Temperature – measure of the degree of hotness or coldness
of a substance
Absolute zero – coldest temperature. No molecular motion = 0 Kelvin
-273oC = ______ K
0oC = ______ K
oC + 273 = K
o
20 C = ______ K
100oC = ______ K
*Kelvin is always bigger
Summer Assignment HW#1 p32+ 20, 25, 33, 53, 55, 73
SA HW#1 p32+ 20, 25, 33, 53, 55, 73
20. A student performed an analysis of a sample for the following calcium
content and got the following results:
14.02% 14.91% 14.88%
14.91%
The actual amount is 15.70%. what conclusions can you draw about
the accuracy and precision of these results?
20. A student performed an analysis of a sample for the following calcium
content and got the following results:
14.02% 14.91% 14.88%
14.91%
The actual amount is 15.70%. what conclusions can you draw about
the accuracy and precision of these results?
-very precise (all trials came out dead-on each other)
- lacks accuracy (not close enough to the actual value)
maybe the Triple Beam Balance was off?
M
a) 8.43 cm to millimeters =
33. Perform each conversion.
. .
b) 2.41x102 cm to meters
c) 294.5 nm to centimeters
d) 1.445x104 m to kilometers
e) 235.3 m to millimeters
f) 903.3 nm to micrometers
KHDUdcm. . μ
. .
n
M . . KHDUdcm. . μ
a) 8.43 cm to millimeters = 84.3 mm
33. Perform each conversion.
b) 2.41x102 cm to meters = 0.0241x102 m
c) 294.5 nm to centimeters = 0.00002945 cm
d) 1.445x104 m to kilometers = 1.445x101 km
e) 235.3 m to millimeters = 0.2353 mm
f) 903.3 nm to micrometers = 0.9033 μm
. .
n
25. How many significant figures are in each of the following?
a) 12
b) 1098
c) 2001
d) 2.001 x 103
e) 0.0000101
f) 1.01 x 10-5
g) 100.
h) 22.04030
25. How many significant figures are in each of the following?
a) 12
2
d) 2.001 x 103
4
g) 100.
3?
b) 1098
4
e) 0.0000101
3
h) 22.04030
7
c) 2001
4
f) 1.01 x 10-5
3
g
53. The density of aluminum is 2.70 cm 3 .
Express this value in units of kilograms per cubic meter.
55. A star is estimated to have a mass of 2 x 1036 kg. Assuming a sphere
of radius 7.0 x 105 km, calc the density in g/cm3.
g
53. The density of aluminum is 2.70 cm 3 .
Express this value in units of kilograms per cubic meter.
2.70 g
1 kg 1,000,000 cm3
cm3 1000 g
1 m3
= 2700 kg/m3
55. A star is estimated to have a mass of 2 x 1036 kg. Assuming a sphere
of radius 7.0 x 105 km, calc the density in g/cm3.
2x1039 g
= 1,392,025.7 g/cm3
.
.
10
3
4/3 π (7.0x10 cm)
= 1,000,000 g/cm3
73. Convert the following Celsius temperatures to Kelvin.
a. boiling temp of ethyl alcohol, 78.10C.
=
b. cold winter day, -250C.
=
c. lowest possible temp, -2730C.
d. melting point of NaCl, 8010C.
73. Convert the following Celsius temperatures to Kelvin.
a. boiling temp of ethyl alcohol, 78.10C.
= 351K
b. cold winter day, -250C.
= 248  250K
c. lowest possible temp, -2730C.
= 0K
d. melting point of NaCl, 8010C.
= 1074K
Ch2 Conservation of Mass, History of the Atom,
and Chemical Formulas
Ex: AgNO3 (aq) + NaCl(aq)
NaNO3 (aq) + AgCl (s)
reactants
products
If you add up the # of each type of atom on both sides of the arrow,
you’ll notice they are the same! Why is that?
Ex: AgNO3 (aq) + NaCl(aq)
reactants
NaNO3 (aq) + AgCl (s)
products
Law of Cons of Mass/Energy
Matter cannot be created or destroyed, it only changes form.
You may see these same compounds in other reactions,
but they will always have the same chemical formula. Why is that?
Ex: AgNO3 (aq) + NaCl(aq)
reactants
NaNO3 (aq) + AgCl (s)
products
Law of Cons of Mass/Energy
Matter cannot be created or destroyed, it only changes form.
Law of Definite Proportion (Proust’s Law) – a compound always contains
the same proportion of elements by mass.
Some chemical formulas look the same but are slightly different. Why is that?
Ex: AgNO3 (aq) + NaCl(aq)
reactants
NaNO3 (aq) + AgCl (s)
products
Law of Cons of Mass/Energy
Matter cannot be created or destroyed, it only changes form.
Law of Definite Proportion (Proust’s Law) – a compound always contains
the same proportion of elements by mass.
Law of Multiple Proportions – 2 elements form a series of compounds,
the ratios of masses can be reduced to simple whole #’s.
Ex: Experimentally, 1g of C combines w 1.33g O2,
but sometimes 1g of C combines w 2.66g O2.
Leads us to believe if there is CO, there is also CO2.
But always whole numbers! No fractions of an atom!
No C½O !
Here’s a table of subatomic particles:
Subatomic particles
Particle
Symbol
Charge
Mass in kg
Mass in amu
Proton
p+
+1
1.67x10-27
1
Electron
e–
–1
9.11x10-31
1/1840
Neutron
no
0
1.67x10-27
1
Why is this important?
Subatomic particles
Particle
Symbol
Charge
Mass in kg
Mass in amu
Proton
p+
+1
1.67x10-27
1
Electron
e–
–1
9.11x10-31
1/1840
Neutron
no
0
1.67x10-27
1
Commit the charges to memory!
Be aware of the masses.
(So that when you see them, you will say, “Oh yeah, I knew that.”)
Commit to memory that the mass of an electron is so small that we won’t
include electrons in the mass of the atom…only the protons and neutrons.
Writing Symbols
Ex: What on earth do those numbers mean?!?
23
11 Na
Writing Symbols
Ex:
total mass (protons and neutrons)
23
11 Na
total number of protons (and therefore electrons.)
To be electrically neutral, and atom has equal protons and electrons.
electrons exist in energy level that
surround the nucleus
protons and neutron exist is the nucleus
11p
12n
This picture has MANY inaccuracies…
can you name them?
Don’t worry, soon you will!
Summer Assignment HW#2 p74+ 23,33,35,45,46,47,49
Summer Assignment HW#2 p74+ 23,33,35,45,46,47,49
23. When mixtures of gaseous H2 and gaseous Cl2 react, a product forms that has
the same properties regardless of the relative amounts of H2 and Cl2 used.
a. How is this result interpreted in terms of the law of the definite proportion?
b. When a volume of H2 reacts with an equal volume of Cl2 at the same
temperature and pressure, what volume of product having the formula
HCl is formed?
23. When mixtures of gaseous H2 and gaseous Cl2 react, a product forms that has
the same properties regardless of the relative amounts of H2 and Cl2 used.
a. How is this result interpreted in terms of the law of the definite proportion?
b. When a volume of H2 reacts with an equal volume of Cl2 at the same
temperature and pressure, what volume of product having the formula
HCl is formed?
a. A compound always contains the same proportion of elements by mass.
One of the elements limits how much product will form:
b. H2(g) + Cl2(g)  2HCl(g)
33. What are the symbols of the following elements:
gold, silver, mercury, potassium, iron, antimony, tungsten?
35. What are the symbols of the following nonmetals:
fluorine, chlorine, bromine, sulfur, oxygen, phosphorus?
45. An atom has 9 protons and 10 neutrons in the nucleus.
What is its symbol?
33. What are the symbols of the following elements:
gold, silver, mercury, potassium, iron, antimony, tungsten?
Au Ag
Hg
K
Fe
Sb
W
35. What are the symbols of the following nonmetals:
fluorine, chlorine, bromine, sulfur, oxygen, phosphorus?
F2
Cl2
Br2
S
O2
P
Why the 2’s? Our chemistry greeting – ‘HNOFClBrI to ya!’ (You’ll see.)
45. An atom has 9 protons and 10 neutrons in the nucleus.
What is its symbol?
Fluorine
46. Write the atomic symbol (AZ X) for each of the isotopes described below.
a. Z = 8, number of neutrons = 9
b. the isotope of the chlorine in which A = 37
c. Z = 27, A = 60
d. number of protons = 26, number of neutrons = 31
e. the isotope of I with a mass number of 131
f. Z = 3, number of neutrons = 4
46. Write the atomic symbol (AZ X) for each of the isotopes described below.
17 O
a. Z = 8, number of neutrons = 9
8
b. the isotope of the chlorine in which A = 37
c. Z = 27, A = 60
37 Cl
17
60 Co
27
d. number of protons = 26, number of neutrons = 31
e. the isotope of I with a mass number of 131
f. Z = 3, number of neutrons = 4 73Li
131 I
53
57 Fe
26
47. What is the symbol for an ion with 63 protons, 60 electrons,
and 88 neutrons?
49. What is the symbol of an ion with 16 protons, 18 neutrons,
and 18 electrons?
47. What is the symbol for an ion with 63 protons, 60 electrons,
and 88 neutrons?
149 Eu+3
63
49. What is the symbol of an ion with 16 protons, 18 neutrons,
and 18 electrons?
34 S2–
16
Ch2 Periodic Table and Naming Compounds
The periodic table has many secrets, including oxidation numbers.
+1
0
+3 +/-4 -3 -2 -1
+2
(
usually +2
)
Ch2 Periodic Table and Naming Compounds
The periodic table has many secrets, including oxidation numbers.
Each of these columns shares similar bonding characteristics,
+1
so they are referred to as families, or groups.
0
+2 The rows are called periods.
+3 +/-4 -3 -2 -1
(
usually +2
)
Naming Compounds
Binary ionic compounds – cation (+) and anion (–)
Put cation 1st, end the anion with ‘ide.’
Ex1)
NaCl sodium is the cation, chloride is the anion → sodium chloride
CaS calcium is the cation, sulfide is the anion → calcium sulfide
Li3N lithium is the cation, nitride is the anion → lithium nitride
CuCl
CuCl2
FeO
Fe2O3
Al2O3
copper is the cation, chloride is the anion → copper chloride
How do we differentiate between the two?
copper is the cation, chloride is the anion → copper chloride
Naming Compounds
Binary ionic compounds – cation (+) and anion (–)
Put cation 1st, end the anion with ‘ide.’
Ex1)
NaCl sodium is the cation, chloride is the anion → sodium chloride
CaS calcium is the cation, sulfide is the anion → calcium sulfide
Li3N lithium is the cation, nitride is the anion → lithium nitride
CuCl copper is the cation, chloride is the anion → copper chloride
Since there are one of each, this copper must be (+1)
since chloride is ALWAYS (–1). Write it as copper (I) chloride
CuCl2 copper is the cation, chloride is the anion → copper chloride
Since there is one of copper and 2 chlorides, this copper must be (+2)
since chloride is ALWAYS (–1). Write it as copper (II) chloride
FeO iron (II) oxide
Fe2O3 iron (III) oxide
Al2O3 aluminum oxide (no roman numerals  Al is always +3)
These are rules you should know from regular chemistry!
If these rules don’t make sense, You Tube it!
Naming Compounds
Compounds containing polyatomic ions – must be memorized!
Most common contain oxygen – called oxyanions
CO32– carbonate
ClO–
hypochlorite
HCO3– bicarbonate
ClO2–
chlorite
NO2–
nitrite
ClO3–
chlorate
NO3–
nitrate
ClO4–
perchlorate
SO32– sulfite
CrO42– chromate
SO42– sulfate
Cr2O72– dichromate
PO43– phosphate
O22–
peroxide
C2H3O2– acetate
C2O42– oxalate
OH –
hydroxide
The blue oxyanions will be on a Ch2 Quiz the 3rd week of school!
Ex2)Name:
Na2SO4 sodium sulfate
Fe(NO3)3 iron (III) nitrate
Naming Compounds
Covalent compounds (nonmetals)
– use prefixes (mono not needed on first element)
– still end in ‘ide’
Ex3) N2O
NO
NO2
N2O3
N2O4
N2O5
dinitrogen monoxide
nitrogen monoxide
nitrogen dioxide
dinitrogen trioxide
dinitrogen tetroxide
dinitrogen pentoxide
Naming Compounds
Acids
– use ‘hydro’ when no oxygen present, keep root of base
– ‘ate ends in ‘ic’
– ‘ite ends in ‘ous’
Ex4) HCl
HClO
HClO2
HClO3
HClO4
hydrochloric acid
hypochlorous acid
chlorous acid
chloric acid
perchloric acid
Summer Assignment HW#3 p76+ 55,59,61,69,77
Summer Assignment HW#3 p76+ 55,59,61,69,77
55. Which of the following sets of elements are all in the same group
in the periodic table?
A. Fe, Ru, Os
C. Sn, As, S
B. Rh, Pd, Ag
D. Se, Te, Po
55. Which of the following sets of elements are all in the same group
in the periodic table?
A. Fe, Ru, Os
D. Se, Te, Po
59. Would you except each of the following atoms to gain or lose electrons
when forming ions? What ion is the most likely in each case?
A. Na
C. Ba
E. Al
B. Sr
D. I
F. S
59. Would you except each of the following atoms to gain or lose electrons
when forming ions? What ion is the most likely in each case?
A. Na
C. Ba
Na+
B. Sr
E. Al
Ba+2
D. I
Sr+2
Al+3
F. S
I1-
S2-
61. Name each of the following compounds:
A. NaCl
C. CaS
B. Rb2O
D. AlI3
61. Name each of the following compounds:
A. NaCl
C. CaS
sodium chloride
B. Rb2O
calcium sulfide
D. AlI3
rubidium oxide
aluminum iodide
69. Name each of the following compounds:
A. CuI
F. S4N4
B. CuI2
G. SF6
C. CoI2
H. NaOCl
D. Na2CO3
I. BaCrO4
E. NaHCO3
J. NH4NO3
69. Name each of the following compounds:
A. CuI
copper(I) iodide
F. S4N4
tetrasulfur tetranitride
B. CuI2
copper(II)iodide
G. SF6
sulfur hexafluoride
C. CoI2
cobalt(II)iodide
H. NaOCl (NaClO)
sodium hypochlite
D. Na2CO3
sodium carbonate
I. BaCrO4
barium chromate
E. NaHCO3
J. NH4NO3
sodium hydrogen carbonate (good) ammonium nitrate
sodium bicarbonate (better)
77. The formulas and common names for several substances are given below.
Give the systematic names for these substances.
a. sugar of lead, Pb(C2H3O2)2
b. blue vitrol, CuSO4
c. quicklime, CaO
d. Epsom salts, MgSO4
e. milk of magnesia, Mg(OH)2
f. gypsum, CaSO4
g. laughing gas, N2O
77. The formulas and common names for several substances are given below.
Give the systematic names for these substances.
a. sugar of lead, Pb(C2H3O2)2
lead (II) acetate
b. blue vitrol, CuSO4
copper (II) sulfate
c. quicklime, CaO
calcium oxide
d. Epsom salts, MgSO4
magnesium sulfate
e. milk of magnesia, Mg(OH)2
magnesium hydroxide
f. gypsum, CaSO4
calcium sulfate
g. laughing gas, N2O
dinitrogen monoxide
Ch2B – Writing Formulas
You should already be familiar with this! This is on your ch2 quiz!
Ex1)
sodium nitride
Find sodium on the periodic table, column 1 = (+1)
Find nitrogen on the PT, column 15 = (-3)
crisscross the oxidation numbers:
Na+1
N-3 :
Na3N
sodium nitrate
Na+1
NO3-1 :
NaNO3
Na+1
NO2-1 :
NaNO2
sodium nitrite
Na+1
N-3
Ex2)
vanadium (V) fluoride:
V+5 F-1 : VF5
dioxygen difuoride:
O2F2
rubidium peroxide:
Rb+1 O2-2 : Rb2O2
gallium oxide:
Ga+3 O-2 : Ga2O3
There will be a short review when school starts up, then a Ch2 quiz,
along with NUMEROUS questions on future chapter tests!
PLEASE, learn how to write chemical formulas!
Summer Assignment HW#4 p76 71 – 74
Summer Assignment HW#4 p76 71 – 74
Ch2 Rev WS on Formulas and Naming – extra practice if you need it.
You can ask ?’s on this
on Ch2 Review Day
Ch3 – The Mole
- defined as the # of C atoms in 12 grams of pure 12C.
= 6.02214 x 1023 atoms
- called Avogadro’s number
Why such a strange number?!?
Why not round it to 1 x 1010? This seems a lot more friendly.
Avogadro’s number cancels out the incredibly small mass of a single atom.
You won’t have any problems to solve like this, but it adds to a very complete
understanding of chemistry. We’ll use carbon as an example:
12 g C = 1 mol C = 6.02 x 1023 atoms C
1.67 x10 - 24 g 12 nucleons 6.022 x10 23 atoms
 12 .0 g mol
1 nucleon
1 atom C
1 mol C
nucleons are all the protons and neutrons in the nucleus.
Molar Mass
Molar Mass – mass in grams of 1 mol of a substance
‘Round all masses to the nearest 0.01g.’
Ex1) Find the molar mass of juglone, C10H6O3.
Use your periodic table to find the mass of each atom
You should see carbon = 12.0g, hydrogen = 1.0g, oxygen = 16.0g
10 C @ 12.0 each = 120.0g
6 H @ 1.0 each =
6.0g
3 O @ 16.0 each = 48.0g
Total = 174.0 g/mol
Ex2) What is the mass of 4.86 mol of calcite, CaCO3.
1 Ca @ 40.1 = 40.1g
1 C @ 12.0 = 12.0g
3 O @ 16.0 = 48.0g
Total = 100.1 g/mol
4.68 mol CaCO 3 100.1 g CaCO 3
 468 .468 g
1 mol CaCO 3
3 sig digs in question, 3 in answer: 468 g CaCO3
Ex3) How many atoms of Si are on a tiny 5.68mg computer chip?
0.00568 g Si 1 mol Si 6.022 x10 23 atoms
32 .1g Si 1 mol Si
= 1.07 x 1020 atoms
3 sig digs in question, 3 in answer.
And don’t forget the units!
Did the conversion table make sense?
We will go over conversion tables at start up.
Summer Assignment HW#5 p122+ 33,37a,39b,47
33. Aluminum metal is produced by passing an electric current through a
solution of aluminum oxide (Al2O3) dissolved in molten cryolite
(Na3AlF6). Calculate the molar masses of Al2O3 and Na3AlF6.
33.Aluminum metal is produced by passing an electric current through a
solution of aluminum oxide (Al2O3) dissolved in molten cryolite
(Na3AlF6). Calculate the molar masses of Al2O3 and Na3AlF6.
2 Al @ 27.0 = 54.0
3 O @ 16.0 = 48.0
102.0g/mol
3 Na @ 23.0 = 69.0
1 Al @ 27.0 = 27.0
6 F @ 19.0 = 114.0
210.0g/mol
37. How many moles of compound are present in 1.00g of NH3?
39. How many grams of compound are present in 5.00 mol of N2H4?
37. How many moles of compound are present in 1.00g of NH3?
1.00 g NH 3 1mole NH 3
 0.0585 mol
17 .0 g NH 3
39. How many grams of compound are present in 5.00 mol of N2H4?
5.00 mol N 2 H 4 32 .0 g N 2 H 4
 160 .0 g N 2 H 4
1mole N 2 H 4
47. Ascorbic acid, or vitamin C (C6H8O6), is an essential vitamin. It cannot be
stored by the body and must be present in the diet. What is the molar mass of
the ascorbic acid? Vitamin C tablets are taken as a dietary supplement. If a
typical tablet contains 500.0 mg of vitamin C, how many moles and how many
molecules of vitamin C does it contain?
47. Ascorbic acid, or vitamin C (C6H8O6), is an essential vitamin. It cannot be
stored by the body and must be present in the diet. What is the molar mass of
the ascorbic acid? Vitamin C tablets are taken as a dietary supplement. If a
typical tablet contains 500.0 mg of vitamin C, how many moles and how many
molecules of vitamin C does it contain?
0.50 g C 6 H 8O 6 1mol C 6 H 8O 6
 0.0028 mol
176 .0 g C 6 H 8 O 6
0.0028 mol C 6 H 8O 6 6.02 x10 23 molecules C 6 H 8 O 6
1mol C 6 H 8O 6
 1.71x10 20 molecules
Ch3.2 Chemical Equations
Ex1)
CH4(g) + O2(g)  CO2(g) + H2O(g)
Hopefully this is familiar to you as well, if not… You Tube it!
CH4(g) + 2 O2(g)  CO2(g) + 2 H2O(g)
Ex2)
C2H5OH(l) + O2(g)  CO2(g) + H2O(g)
C2H5OH(l) + 3 O2(g)  2 CO2(g) + 3 H2O(g)
Summer Assignment HW#6 p125+ 81,82,83,85,88
Summer Assignment HW#6 p125+ 81,82,83,85,88
81. Balance the following equation:
a. Cu(s) + AgNO3(aq)
Ag(s) +
b. Zn(s) + HCI(aq)
c. Au2S3(s) + H2
Cu(NO3)2(aq)
ZnCI2(aq) +
Au(s) +
H2(g)
H2S(g)
82. Balance the following equations:
a. Ca(OH)2(aq) + H3PO4(aq) → H2O(l) + Ca3(PO4)2(s)
b. Al(OH)3(s) + HCl(aq) → AlCl3(aq) + H2O(l)
c. AgNO3(aq) + H2SO4(aq) → Ag2SO4(s) + HNO3(aq)
83. Balance the following equations representing combustion reactions:
a. C12H22O11 (s) + O2(g)
b. C6H6(l) + O2(g)
c. Fe(s) + O2(g)
d. C4H10(g) + O2(g)
e. FeO(s) + O2(g)
CO2(g) + H2O(g)
CO2(g) + H2O(g)
Fe2O3(s)
CO2(g) + H2O(g)
Fe2O3(s)
85. Silicon is produced for the chemical and electronics industries by
the following reactions. Give the balanced equation for each reaction.
a. SiO(s) + C(s) → Si(s) + CO(g)
b. Silicon tetrachloride is reacted with a very pure magnesium,
producing silicon and magnesium chloride.
c. Na2SiF6(s) + Na(s) → Si(s) + NaF(s)
88. The electrolysis of concentrated brine solutions is an important source of
NaOH, H2, and Cl2 for the chemical industry.
The reaction is
NaCl(aq) +
Balance this equation.
H2O(l)
ELECTRICITY
Cl2(g) + H2(g) + NaOH(aq)
Ch3.3 Stoichiometry
Ex1) What mass of oxygen will react with 96.1g propane, C3H8?
- start with a balanced equation:
C3H8 + O2  CO2 + H2O
How did I know to write oxygen as O2? HNOFClBrI to ya!
How did I know that carbon dioxide and water were the products…of
combustion? (Don’t worry, you will too!)
Ex1) What mass of oxygen will react with 96.1g propane, C3H8?
- start with a balanced equation:
1 C3H8 + 5 O2  3 CO2 + 4 H2O
- start the conversion table with the given:
96.1g C3H8
- now get outta grams and into moles…
Ex1) What mass of oxygen will react with 96.1g propane, C3H8?
- start with a balanced equation:
1 C3H8 + 5 O2  3 CO2 + 4 H2O
- start the conversion table with the given:
- now get outta grams and into moles…
96.1g C3 H 8 1 mol C3 H 8
44.0g C3 H 8
- now use the balanced chemical equation to switch from moles of given
to moles of what you wanna switch to…
Ex1) What mass of oxygen will react with 96.1g propane, C3H8?
- start with a balanced equation:
1 C3H8 + 5 O2  3 CO2 + 4 H2O
- start the conversion table with the given:
- now get outta grams and into moles…
- now use the balanced chemical equation to switch from moles of given
to moles of what you wanna switch to…
96.1g C3 H 8 1 mol C3 H 8 1 mol O 2
44.0g C3 H 8 1 mol C3 H 8
- now use the molar mass of oxygen to get into grams of oxygen…
Ex1) What mass of oxygen will react with 96.1g propane, C3H8?
- start with a balanced equation:
1 C3H8 + 5 O2  3 CO2 + 4 H2O
- start the conversion table with the given:
- now get outta grams and into moles…
- now use the balanced chemical equation to switch from moles of given
to moles of what you wanna switch to…
96.1g C3 H 8 1 mol C3 H 8 1 mol O 2 32.0 g O 2
 69 .9 g O 2
44.0g C3 H 8 1 mol C3 H 8 1 mol O 2
- now use the molar mass of oxygen to get into grams of oxygen…
Summer Assignment HW#7 p126 91,92,96a
Summer Assignment HW#7 p126 91,92,96a
91. The reusable booster rockets of the U.S. space shuttle employ a mixture of
aluminum and ammonia perchlorate for fuel. A possible equation for this rxn is
3Al(s) + 3NH4ClO4(s)
Al2O3(s) + AlCl3(s) + 3NO(g) +6H2O(g)
What mass of NH4ClO4 should be used in the fuel mixture for 1000g of Al?
91. The reusable booster rockets of the U.S. space shuttle employ a mixture of
aluminum and ammonia perchlorate for fuel. A possible equation for this rxn is
3Al(s) + 3NH4ClO4(s)
Al2O3(s) + AlCl3(s) + 3NO(g) +6H2O(g)
What mass of NH4ClO4 should be used in the fuel mixture for 1000g of Al?
1000g Al 1mol Al 3mol NH 4 117.5g NH 4 ClO 4
 4350 g
27.0g Al 3mol Al
1mol NH 4 ClO 4
92. One of relatively few reactions that takes place directly between two solids at
room temperature is
Ba(OH)2 8H2O(s) + NH4SCN(s)
Ba(SCN)2(s) + H2O(l) + NH3(g)
In this equation, the 8H2O in Ba(OH)2 8H2O indicates the presence of eight
water molecules. This compound is called barium hyroxide octahydrate.
a. Balance the equation.
b. What mass of ammonia thiocyanate (NH4SCN) must be used if it is to react
completely with 6.5 g barium hydroxide octahydrate ?
92. One of relatively few reactions that takes place directly between two solids at
room temperature is
Ba(OH)2 8H2O(s)+ 2NH4SCN(s)
Ba(SCN)2(s)+10H2O(l) +2NH3(g)
In this equation, the 8H2O in Ba(OH)2 8H2O indicates the presence of eight water
molecules. This compound is called barium hyroxide octahydrate.
a. Balance the equation.
b. What mass of ammonia thiocyanate (NH4SCN) must be used if it is to react
completely with 6.5 g barium hydroxide octahydrate ?
6.5g Ba(OH) 2  8H 2 O
1mol Ba(OH) 2  2mol NH 4SCN 76.1g NH 4SCN
315.3g Ba(OH) 2  1mol Ba(OH) 2  1mol NH 4SCN
 3.1g
96. Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3)
with acetic anhydride (C4H6O3). The balanced equation is
C7H6O3 + C4H6O3
C9H8O4 + HC2H3O2
a. What mass of acetic anhydride is needed to completely consume
1.00x102 g salicylic acid?
96. Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3)
with acetic anhydride (C4H6O3). The balanced equation is
1C7H6O3 + 1C4H6O3
1 C9H8O4 + 1HC2H3O2
a. What mass of acetic anhydride is needed to completely consume
1.00x102 g salicylic acid?
1.00x10 2 g (sa) 1mol (sa) 1mol (aa) 102.0g (aa)
 73 .9 g
138.0g (sa) 1mol (sa) 1mol (aa)