Download Chapter 3 - Significant Figures - Scientific Measurement

AP Chemistry
Welcome to AP Chemistry. This class will utilize everything that you have learned in Chemistry and will build on that by adding new
topics and intertwining others together so that they can be applied to real life situations. This class moves at an incredible pace.
This is a college class. Unlike most other AP classes, we essentially have a little over one year of material to cover in just over three
quarters of a year of class. We are the first AP exam of the year. The exam is scheduled for May 2, 2016.
Our test is also different than the other tests. There are basically two parts: Multiple Choice (60 questions – 90 minutes) and Free
Response (4 short questions and 3 long questions – 90 minutes). There is no penalty for guessing on the multiple choice questions.
Something different though exists for the free response questions. These sections build, for example, one free response question
may have 5 or 6 parts which are all related to each other with each free response question valued between 10 and 15 points. If for
some reason you can’t quite get the answer for Part A of a question, then how do you even attempt Part B through Part F? Easy,
you make up your own problem. For example, let’s say that the question asks you to write the balanced reaction for the complete
combustion of methanol. You briefly panic because you don’t know what methanol is, however you remember the formula for
methane and write the correct balanced complete combustion reaction for it. Sure you will lose a point, but the other points are still
yours provided you can answer the remaining parts using your new problem. You will need a scientific calculator (TI-84 or TI-NSpire)
for the class, however please note that on some parts of the AP exam you will not be allowed to use your calculator. The College
Board assumes that you are good at math and provided the calculations don’t require exponents, logs, or natural logs for example,
they expect you to do it in your head.
How can I be successful in this class? Simple, do not get behind. Do your homework. Do not copy from anyone else. I won’t know if
you copied when you first turn the work in, but it’s easy to figure it out when you take the tests. Come in for help if you need it.
Form a study group with students within the class. You will be expected to read one to two chapters each week. The reading level
of the book is college level, much higher than the Chemistry book. You can access the online textbook by using the URL
www.coxscience.org. Most of the material is password protected. Your initial password is your student ID number. If you had me
for chemistry, then you may already have an account. There will be work over the breaks (winter and spring). We will try to end the
introduction of new content around the middle of April. At which point we will begin taking practice AP exams and will continue to
exam day.
We will do labs, typically one every other week or so. The labs require multiple days to complete. Unlike Chemistry, the labs will not
be cookbook style. Instead, you will be given a problem to solve and some guidance with respect to any techniques or equipment
that needs to be employed. You will also be advised of any associated hazards. As AP students you will be expected to follow the
lab safety and cleanup procedures. You will be required to turn in complete lab reports written to a provided specification. The
intent of the lab is to get you to think. The right answer is important, but not as important as how you obtained it. You will be
graded on procedure, completeness, skill, etc. Think of a lab report as a 6 to 12 page paper.
Please read chapters 1, 2, and 3. We will review this material once class starts, however we will complete the first three chapters in
a little over a week. There will be a quiz soon after school starts covering this material. What am I expected to do with this packet?
I need you to have it completed as best that you can by the time you come to class on August 24, 2015. I do not want you to do this
packet in June. Depending on you, maybe not even July. If you are a procrastinator, start in July. If not, then early August will
probably work. The purpose of this packet is so that you don’t come to class on the first day cold. Chemistry is not like riding a bike,
you do need to practice. You should know and be proficient with everything in this packet. This packet is our starting point. There
will be a lot of homework, typically 4 days a week, not counting labs. How can you minimize the homework? Know the content of
this packet and have it completed before you come the first day. Remember we can skip over the material that you know, which
translates into less homework. By the way, the last few pages of the packet are the periodic table and equations that are provided
to you for use on the AP exam. On the exam you will not be allowed to use anything else.
We will have fun. We will work hard. In the end it will all be worth it. I am here to help you and support you. You must be willing
to help yourself. You will be amazed as to what you know and can do at the end of the year.
I always check my email ([email protected]). If you have a question, email me. Once school starts in the fall, we’ll establish
before and after school times that I can be available to help you outside of the class. You need to be responsible for you. I will do
everything that I can to help you, but you have to do your part. Together we will get through it.
Good luck. I look forward to working with you in the fall.
John Cox
Name ________________________________________________________
Significant Figure, Scientific Notation, and Density
A. Round the following to the specified number of significant figures:
1.
_______________
2188.3 g (3 sig fig)
2.
_______________
0.0001978 kg (2 sig fig)
2.
_______________
0.00001430 cm
B. Put the following into scientific notation:
1.
C.
_______________
2397.8 cm
Do the following calculations to the correct number of significant figures:
1.
Find the mass of plastic if you have 35 cm3. (density = 1.38 g/cm3)
2.
Calculate the density of a rock that has a mass of 21.58 grams that causes the water in a graduate to rise from 20.0 mL
to 25.4 mL.
Atomic Structure
A.
Complete the following table:
Number
Isotope
1
235
92 U
2
13
6C
Atomic number
Mass number
p+
e-
n0
p+
e-
n0
B. Using a periodic table, complete the following table:
Number
Element
Symbol
Atomic number
Mass number
1
1
2
Os
Isotopes
175
176
A. There are two naturally occurring isotopes of lutetium, 71 Lu (97.39%, 174.9407 amu) and 71 Lu (2.61%, 175.9426 amu).
Calculate the atomic mass as it would appear on the periodic table.
B. The two main isotopes of silver are
107
Ag (106.905 amu) and
a natural mixture.
Electron Configuration
Complete the electron configuration for each element:
Number
Element
1
Fe
2
Mo
3
Uuo
# of e-
Electron configuration
109
Ag (108.905 amu). Calculate the percent of silver-109 in
Periodic Trends – Valence Electrons, Common Ions, and Trends
A. For the atoms in the following table, write the number of valence electrons:
Atom
# of Valence e-
Atom
# of Valence e-
Atom
Mg
V
Rn
He
Se
S
# of Valence e-
B. For the atoms in the following table, write the charge of the most common ion (i.e. +1, -2, etc.):
Atom
C.
Usual Ionic Charge
Atom
Usual Ionic Charge
Atom
Mg
I
N
Se
O
Ga
Usual Ionic Charge
For the atoms in the following table, write the total number of electrons in each ion:
Ion
# of e-
Ion
# of e-
Ion
F-1
Cu+2
Fr+1
S-2
Fe+3
Cr+6
D. Sort the following as indicated:
1. Increasing atomic size (Cl, F, Cs, Co, Si).
# of e-
_____, _____, _____, _____, _____
Increasing 
2. Decreasing ionization energy (Br, Ne, N, Ca, Fe). _____, _____, _____, _____, _____
Decreasing 
3. Increasing electronegativity (Xe, F, O, S, Fr).
_____, _____, _____, _____, _____
Increasing 
Ionic Compounds
A. For each atom in the table, provide the number of valence electrons, ionic symbol, ion type, and ion name.
Atom
Valence e-
Ionic Symbol
Ion Type
Ion Name
Anion/Cation
Fr
S
B. For each pair of atoms in the table, provide the formula unit and name of the ionic compound.
Atoms
Formula Unit
Name of Ionic Compound
Rb and P
C.
Atoms
Formula Unit
Name of Ionic Compound
Ga and S
For each ionic compound in the table, provide the formula unit.
Name of Ionic Compound
Barium Fluoride
Formula Unit
Name of Ionic Compound
Gallium Oxide
compound in the table, draw the ion dot structure.
Ionic Compound
SrF2
Dot Structure
Formula Unit
D. F
or each
ionic
Molecular Structures
Draw the following molecular structures. Be sure to include all lone pairs.
Compound
Structure
Polarity
(Bond)
Ionic/
Polar/
Non-Polar
(I/P/NP)
I2
HCN
BCl3
C3H8
O3
Geometry
Polarity
(Molecular)
Resonance
Coordinate
Covalent
Bond
(Y/N)
(Y/N)
Polar/NonPolar
(P/NP)
Nomenclature and Charges
A. Name the following compounds:
1.
HfF4
________________________________
5.
Br2O
________________________________
2.
HCl (aq)
________________________________
6.
HClO
________________________________
3.
SiI4
________________________________
7.
Tb2(Cr2O7)3 ________________________________
4.
Mo(OH)5
________________________________
B. Write the formulas for the following compounds:
C.
1.
Silver telluride
__________________
5.
Sulfurous acid
__________________
2.
Hydrofluoric acid
__________________
6.
Rhenium (VI) phosphite
__________________
3.
Diarsenic pentasulfide
__________________
7.
Diphosphorus tetrasulfide
__________________
4.
Hydrocyanic acid
__________________
Determine the charge on all of the atoms in the following compounds:
Os(CrO4)4
_____________________________________________________________________
Molar Mass
A. Calculate the molar mass to two (2) decimal places:
1.
CaSO4
_______________
3.
CO2
_______________
2.
HNO3
_______________
4.
Al(NO3)3
_______________
B. Perform the following calculations:
1. A sample of Al2O3 contains 2.43 x 104 g. How many moles of Al are present?
2.
How many phosphorus atoms are present in 23.4 moles of P2O5?
3.
How many grams of carbon are in a piece of steel that contains 3.287 x 1034 atoms of carbon?
4.
How many liters of oxygen are present in a sample of CO2 that weighs 3.40 x 10-4 g at STP?
5.
How many oxygen atoms are present in a 5.63 liter container of pure oxygen gas at STP?
Complete Reactions, Balance Equations, and Classify Reaction Types
Completed Reactions
Reaction Type
1.
____C2H2(g) + ____O2(g)  ______________________________________
__________________________
2.
____Zn(s) +____ CuSO4(aq)  ____________________________________
__________________________
3.
____Cl2(g) + ____KI(aq)  _______________________________________
__________________________
4.
____H2O2(l)  ________________________________________________
__________________________
5.
____Sc(s) + ____I2(s)  _________________________________________
__________________________
6.
____Cd(s) + ____S8(l)  ________________________________________
__________________________
7.
____H2SO4(aq) + ____NaOH(aq)  ________________________________
__________________________
8.
____C2H5OH(l) + ____O2(g)  ____________________________________
__________________________
9.
____Sr(s) + ____N2(g)  ________________________________________
__________________________
10. ____Fe2O3(s) + ____H2SO4(aq)  _________________________________
__________________________
Stoichiometry Review and Practice
Calculate the following problems. Remember to balance the equations first.
1. Aluminum oxide is produced in a combination reaction of aluminum and oxygen gas. How many grams of oxygen are
required to react with 25.0 grams of Al?
2.
When excess barium reacts with 355 grams of lead (IV) nitrate, how many atoms of lead will be replaced?
3.
How many liters of oxygen are required to burn 45.00 grams of ethanol (C2H5OH)?
4.
When 7.59 grams of tin react with an excess of hydrochloric acid (HCl), hydrogen gas and 10.18 grams of tin (II) chloride
is formed. Calculate the theoretical and percent yield of tin (II) chloride.
Theoretical Yield: _______________
5.
Percent Yield: _______________
12.75 grams of Li react with 25.65 grams of BaCl2 to produce LiCl and Ba. What is the mass of LiCl produced?
Limiting Reagent: _______________
Excess Reagent: _______________
Mass of LiCl: _______________
Phase Diagrams
Use the diagram below to answer the following questions.
1.
What is the normal melting point of this substance?
2.
What is the normal boiling point of this substance?
3.
What is the normal freezing point of this substance?
4.
At what temperature do the gas and liquid phases become
indistinguishable from each other?
Solutions
A. Molarity
1. What is the molarity of a 3.0 L solution containing 3.2 moles of NaCl?
2.
What is the molarity of a solution containing 10.6 g of MgO and 1345 mL of H2O?
B. Molality
1. What is the molality of a solution containing 350.0 g of water and 3.44 moles of K3PO4?
2.
C.
What is the molality of a solution containing 500.0 g H2O and 138 g of KBr ?
Colligative Effects: Freezing Point Depression – Boiling Point Elevation
What are the boiling point and freezing points of a solution that contains 2.88 moles of benzene, C6H6, in 1.550 kilograms of
the solvent, carbon tetrachloride? The boiling point of carbon tetrachloride is 76.8 oC. The freezing point of carbon
tetrachloride is –22.8 oC. The molal boiling point constant for carbon tetrachloride is 5.02 oC/m and the molal freezing point
constant is 29.8 oC/m.
Gas Laws
Convert your final answer as follows: temperature in Celsius (°C), volume in liters (L), and pressures in kilopascals (kPa).
1. A fire extinguisher with a volume of 3.0 L is filled with 150.0 g of CO2. What is the pressure at 20.0 °C?
2.
An experimental research submarine with a volume of 15,000 L has an internal pressure of 1.2 atm. If the pressure of the
ocean breaks the submarine forming a bubble with a pressure of 250 atm pushing on it, how big will that bubble be?
3.
If 540.0 mL of nitrogen at 0.00 °C is heated to a temperature of 100.0 °C what will be the new volume of the gas?
4.
Air contains 20.95% oxygen. If 80.0 L of air is collected at 20.0 °C and the atmospheric pressure is 96.00 kPa, what is the
partial pressure of the oxygen?
5.
The temperature of a sample of gas in a steel container at 30.0 kPa is increased from -100.0 °C to 100.0 °C. What is the final
pressure inside the tank?
6.
If equal amounts of helium and argon are placed in a porous container and allowed to escape, which gas will escape faster
and how much faster? Report your answer to 3 significant figures.
7.
A container holds three gases: oxygen, carbon dioxide, and helium. The partial pressures of the three gases are 2.00 atm,
3.00 atm, and 4.00 atm, respectively. What is the total pressure inside the container?
8.
Rank the following gases in order of effusion (from slowest to fastest):
a.
SO3
_______
Slowest
b.
_______
F2
c.
_______
Cl2
_______
d.
_______
Fastest
CO
e.
H2
Thermochemistry
Label each graph as endothermic or exothermic. Label the reactants, the products, and show the change in enthalpy (ΔH, >0,
<0, ↑, ↓).
Reaction Rates and Equilibrium
Label the reactants, products, activation energy with a catalyst, and activation energy without a catalyst.
Acids and Bases
Complete the following table:
pH
pOH
[H+]
[OH-]
5.3
4.6
1.2 x 10-12
9.7 x 10-10
Oxidation-Reduction
A. Determine the oxidation number of oxygen in the following:
1. O2
______
2. H2O
______
3.
H2O2
______
B. Determine the oxidation number of sulfur in the following:
1. SO3
______
2. SO4-2
______
3.
K2S
______
C.
In the following equations identify the element being oxidized and the element being reduced.
Oxidized
Reduced
1.
Al(s) + MnO2(s)  Al2O3(s) + Mn(s) ____________________ ____________________
2.
K(s) + H2O(l)  KOH(aq) + H2(g)
____________________ ____________________
3.
HgO(s)  Hg(l) + O2(g)
____________________ ____________________
4.
P4(s) + O2(g)  P4O10(s)
____________________ ____________________
INFORMATION IN THE TABLE BELOW AND IN THE TABLES ON PAGES 3-5 MAY BE USEFUL IN ANSWERING
THE QUESTIONS IN THIS SECTION OF THE EXAMINATION.
-2-
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STANDARD REDUCTION POTENTIALS IN AQUEOUS SOLUTION AT 25∞C
E ∞(V)
Half-reaction
-
F2 ( g) + 2 e
Æ
-
2F
2+
Æ
Co
Æ
Au(s)
Æ
2 Cl -
O2 (g) + 4 H + + 4 e -
Æ
2 H 2 O(l )
Br2 (l ) + 2 e
Æ
2 Br -
2 Hg2+ + 2 e -
Æ
Hg2+ + 2 e -
Hg22+
Æ
Hg(l )
Æ
Ag(s)
Æ
2 Hg(l )
Æ
Fe 2+
Æ
2 I-
Æ
Cu(s)
Æ
Cu(s)
Æ
Cu+
Sn 4+ + 2 e -
Æ
Sn 2+
S(s) + 2 H + + 2 e -
Co
3+
Au
+e
+ 3e
3+
-
Cl2 (g ) + 2 e
Ag + e
+
Hg2
Fe
-
+e
3+
-
+ 2e
2+
-
-
-
I 2 (s) + 2 e -
Cu+ + e Cu
2+
+ 2e
Cu
2+
-
+e
-
Æ
-
H 2S(g )
+
Æ
Pb
+ 2e
-
H2 (g)
2+
Æ
Pb(s)
Sn
2+
+ 2e
-
Æ
Sn(s)
-
Æ
Ni(s)
+ 2e
-
Æ
Co(s)
+ 2e
-
Æ
Cd(s)
Æ
Cr 2+
Fe 2+ + 2 e -
Æ
Fe(s)
-
Æ
Cr(s)
Æ
Zn(s)
Æ
H 2 ( g ) + 2 OH -
Æ
Mn(s)
Æ
Al(s)
Æ
Be(s)
Æ
Mg(s)
Æ
Na(s)
Æ
Ca(s)
Æ
Sr(s)
Æ
Ba(s)
Æ
Rb(s)
2H + 2e
Ni
+ 2e
2+
Co
2+
Cd
2+
Cr
Cr
+e
3+
+ 3e
3+
Zn
-
2+
+ 2e
-
2 H 2 O(l ) + 2 e
Mn 2+ + 2 e Al
+ 3e
3+
Be
+ 2e
2+
Mg
2+
Na + e
Sr
2+
Ba
+ 2e
2+
Rb + e
-
-
-
-
+ 2e
+
-
-
+ 2e
2+
-
+ 2e
+
Ca
-
-
-
Æ
K(s)
+
-
Æ
Cs(s)
+
-
Æ
Li(s)
K +e
+
Cs + e
Li + e
-3-
2.87
1.82
1.50
1.36
1.23
1.07
0.92
0.85
0.80
0.79
0.77
0.53
0.52
0.34
0.15
0.15
0.14
0.00
– 0.13
– 0.14
– 0.25
– 0.28
– 0.40
– 0.41
– 0.44
– 0.74
– 0.76
– 0.83
– 1.18
– 1.66
– 1.70
– 2.37
– 2.71
– 2.87
– 2.89
– 2.90
– 2.92
– 2.92
– 2.92
– 3.05
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ADVANCED PLACEMENT CHEMISTRY EQUATIONS AND CONSTANTS
E
v
l
p
ATOMIC STRUCTURE
E = hv
c = lv
h
l=
p = mu
mu
-2.178 ¥ 10 -18
En =
joule
n2
Boltzmann’s constant, k = 1.38 ¥ 10 -23 J K -1
Avogadro’s number = 6.022 ¥ 1023 mol -1
Electron charge, e = -1.602 ¥ 10 -19 coulomb
1 electron volt per atom = 96.5 kJ mol -1
Equilibrium Constants
[A - ]
[HA]
K a (weak acid)
K b (weak base)
K w (water)
K p (gas pressure)
[HB+ ]
[B]
pK a = - log K a , pK b = - log K b
pOH = pK b + log
K p = K c ( RT )
u = velocity
n = principal quantum number
m = mass
Planck’s constant, h = 6.63 ¥ 10 -34 J s
pH = - log [H + ], pOH = - log[OH - ]
14 = pH + pOH
Dn
energy
frequency
wavelength
momentum
Speed of light, c = 3.0 ¥ 108 m s-1
EQUILIBRIUM
[H + ][A - ]
Ka =
[HA]
[OH - ][HB+ ]
Kb =
[B]
K w = [OH ][H + ] = 1.0 ¥ 10 -14 @ 25DC
= K a ¥ Kb
pH = pK a + log
=
=
=
=
K c (molar concentrations)
,
S D = standard entropy
where D n = moles product gas - moles reactant gas
H D = standard enthalpy
THERMOCHEMISTRY/KINETICS
G D = standard free energy
 S D products - S D reactants
DH D = Â DHfD products -Â DH fD reactants
ED
T
n
m
q
c
Cp
DS D =
DG D =
 DGfD products - DGfD reactants
DG D = DH D - T D S D
= - RT ln K = -2.303 RT log K
= -n Ᏺ E D
standard reduction potential
temperature
moles
mass
heat
specific heat capacity
molar heat capacity at constant pressure
Ea = activation energy
k = rate constant
A = frequency factor
DG = DG D + RT ln Q = DGD + 2.303 RT log Q
q = mcDT
DH
Cp =
DT
Faraday's constant, Ᏺ = 96,500 coulombs per mole
of electrons
ln [A ] t - ln [A]0 = - kt
1
1
= kt
[A] t [A]0
ln k =
=
=
=
=
=
=
=
Gas constant, R = 8.31 J mol -1 K -1
= 0.0821 L atm mol -1 K -1
= 62.4 L torr mol -1 K -1
()
= 8.31 volt coulomb mol -1 K -1
- Ea 1
+ ln A
R T
-4-
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GASES, LIQUIDS, AND SOLUTIONS
PV = nRT
Ê
n2 a ˆ
ÁË P + 2 ˜¯ (V - nb) = nRT
V
PA = Ptotal ¥ X A , where X A =
Ptotal = PA + PB + PC + ...
m
n=
M
moles A
total moles
K = D C + 273
PV
PV
1 1
= 2 2
T1
T2
m
D=
V
3kT
3RT
urms =
=
M
m
1 2
KE per molecule = mu
2
3
KE per mole = RT
2
M2
r1
=
M1
r2
molarity, M = moles solute per liter solution
molality = moles solute per kilogram solvent
DT f = iK f ¥ molality
DTb = iK b ¥ molality
p = iMRT
A = abc
P
V
T
n
D
m
u
=
=
=
=
=
=
=
pressure
volume
temperature
number of moles
density
mass
velocity
urms
KE
r
M
p
i
Kf
=
=
=
=
=
=
=
root-mean-square speed
kinetic energy
rate of effusion
molar mass
osmotic pressure
van't Hoff factor
molal freezing-point depression constant
Kb
A
a
b
c
Q
I
q
t
=
=
=
=
=
=
=
=
=
molal boiling-point elevation constant
absorbance
molar absorptivity
path length
concentration
reaction quotient
current (amperes)
charge (coulombs)
time (seconds)
E D = standard reduction potential
K = equilibrium constant
OXIDATION-REDUCTION; ELECTROCHEMISTRY
Gas constant, R = 8.31 J mol -1 K -1
= 0.0821 L atm mol -1 K -1
Q=
I =
[C] c [D] d
a
[A] [B]
= 62.4 L torr mol -1 K -1
, where a A + b B Æ c C + d D
= 8.31 volt coulomb mol -1 K -1
Boltzmann's constant, k = 1.38 ¥ 10 -23 J K -1
q
t
D Ecell = Ecell
log K =
b
K f for H2 O = 1.86 K kg mol -1
RT
D - 0.0592 log Q @ 25D C
ln Q = Ecell
nᏲ
n
K b for H2 O = 0.512 K kg mol -1
1 atm = 760 mm Hg
= 760 torr
nE D
0.0592
STP = 0.00 D C and 1.0 atm
Faraday's constant, Ᏺ = 96,500 coulombs per mole
of electrons
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