Chem II: 8/15/13
Objectives:
• Distribute Textbooks
• Address Graduate Cylinder Lab
• Review Pre-Assessment Test
• Gallery Walk Review
• Introduce Stoichiometry Lab
Homework:
• Work on Review Packet
• Pre-Lab Qts. from Stoichiometry Lab
Experimental Variables
• Independent variable
- variable “I” control in the experiment.
- Always plot on x-axis
• Dependent Variable
- variable depends on the independent variable
- Always plot on y-axis
Interpreting Graphs: Slope
Slope= rise/ run
Interpreting Graphs: Slope
What is the slope for this line?
What does the slope represent?
Interpreting Graphs: Slope
Chem II: 8/15/13
Objectives:
• Review and apply Chemistry I concepts.
Homework:
• Review chemistry I concepts with packet
and webpage enrichment problems.
• Read and complete pre-lab qts. for
Stoichiometry Lab
Analyzing Quantitative Data
• Precision :
• Accuracy:
Accuracy vs. Precision
• Accurate Results:
When you compare your results with the true
value.
• Precise Results:
• When you compare your experimental
results with one another.
Significant Figures
Significant Figures:
• The definite numbers in a measurement
plus the first estimated number.
• Significant figures are directly related to
the accuracy of a measurement.
Calculating Measurements
• Multiplying and Dividing:
The # of sig. figs. in the answer is the same as
the measurement with the least number of
significant figures.
Addition and Subtraction:
The # of sig. figs. in the answer is the same as
the measurement with the least number of
decimal places.
Metric Conversions
•King Henry died by drinking chocolate milk.
•Prefixes based on a power of 10.
Metric to English
k  h  dk  base  d  c  m
a. How many meters are in a 100 yard football field?
b. How many centimeters are in 2 feet ?
c. Convert 4 pounds (lbs.) to milligrams?
Scientific Measurement
Classification of Matter
Classifying Matter:
Substances vs. Mixtures
Substances
•Definite chemical
make-up from sample
to sample.
•Elements or
compounds
•Ex. Silicon chip or H2O
Mixtures
•Varied chemical makeup from sample to
sample.
• 2 or more substances
physically combined
•Homo or Hetero
Mixtures
• Pizza and salt water
Elements
type of matter that maintains it properties.
•Smallest
Each element represents a different atom (natural or
•synthetic)
A symbol is used to represent each element.
Compound
Chemical Combination of substances in a fixed
•amount.
compound has a unique chemical formula.
•Ex.Each
Sodium chloride = NaCl
The chemical combination of substances produces
•new
properties.
Sodium (Na)
(NaCl)
+
Chlorine (Cl)
=
Salt
Heterogenous Mixures
Observe multiple phases (parts) because
the substances do not mix well. Substances
have a low solubility for one another.
Homogenous Mixtures
Substances mix so well it looks like one phase.
Substances have a high solubility for one another
“Like dissolves like.”
Homongenous Mixtures
• Also called solutions.
• Solutions:
-Solute: what is dissolved
-Solvent: what dissolves
Solubility= the ability of the solute to
dissolve in the solvent.
.
NaCl + H O
2
Chemical vs. Physical Change
Chemical Change:
• Matter’s chemical make-up changes producing
new matter with different properties.
• If reversible only through chemical changes.
Ex. Iron rusting: Fe + O2 -----> FeO
Physical Change:
• Matter’s physical make-up changes, but the
matter’s chemical make-up stays the same.
• Can be reversible through physical changes.
Ex. Making Lemonade
Intramolecular Forces
Forces within a single compound that holds the atoms together. Also called
chemical bonds.
H O compound
2
Types of Chemical Changes
•
•
•
•
•
•
•
Combustion
Decaying
Digesting
Baking
Neutralization (acidic and basic chemicals)
Growing
Spoiled
Intermolecular Forces
Forces between compounds in a sample of matter.
(group forces)
Types of Physical Changes
•
•
•
•
•
•
Most states of matter
Breaks
Dissolves
Crushes
Cuts
Absorbs
Phase Changes
What kind of forces are affected ?
.
Phases of Matter
Temperature Scales
Temperature only measures the heat energy used to alter the
speed of particles.
•Scientist prefer the Kelvin (K) and Celsius (oC) scales
•K = 273.15 + oC
Visionlearning.com
Molecular Kinetic Theory:
Establishes a relationship between energy flow, speed
of particles, and intermolecular forces during physical
changes.
Changes in state
of matter
evaporation of
water
condensation
of alcohol
deposition of copper
melting of ice cream
Kinetic Energy:
Absorbed or Released
Intermolecular Forces:
Strengthened or
Weakened
Molecular Kinetic Theory:
Establishes a relationship between energy flow, speed
of particles, and intermolecular forces during physical
changes.
Heat Energy
Heat Energy (q) =
• Energy that is transferred between matter of
different temperatures.
• Unit for Energy: Joules (J) or calories (cal)
• Energy does not have mass or volume, therefore it
is NOT classified as matter.
• How does heat energy flow between objects?
Heat Energy Flow
Heat energy flowing between objects:
• System:
The matter you are studying/measuring.
• Surrounding :
The matter (environment) around the system.
• Endothermic Process:
When more heat is absorbed by the system.
• Exothermic Process:
When more heat is released by the system.
Energy Diagrams:
Exothermic or Endothermic?
Energy Diagrams:
Exothermic or Endothermic?
Heat Energy
• Heat energy affects the:
-speed of particles (only detected by thermometers)
-strength of the intermolecular forces
Heat Energy
Matter and Energy
Dalton’s Atomic Theory
1. Atoms are the building blocks of all matter.
2. Atoms cannot be subdivided.
3. Each element has the same kind of atoms.
4. A compound, the different atoms chemically
combine in the same way (fixed composition).
5. Atoms cannot be created or destroyed just
rearranged.
Thomson’s Cathode Tube Experiment
Discovered negatively charged particles in different gases
through this experiment.
l-esperimento-piu-bello-della-fisica.bo.imm.c...
J. J Thomson’s Plum Pudding Model
• If atoms are made of electrons how come most
matter does not shock us?
• Atoms must have positive particles, too.
• He proposed the Plum Pudding Atomic Model
•
An atom is equally
made up of positive
and negative particles.
Rutherford’s Gold Foil Experiment
•
•
•
•
Most of the atom is empty space.
Small dense region composed of
(+) charged particles.
(Nucleus)
Subatomic Particle: Neutron
•What keeps the protons within the
nucleus ?
(Like particles repel each other)
•1932 - James Chadwick discovers that
the nucleus also has neutral particles
present. He called them neutrons.
Bohr’s Model of the Atom
•Electrons travel in fixed, circular
paths
around the nucleus.
•Each path has a specific energy
requirement.
•These circular paths are called energy
levels.
•Limited number of electrons on each http://micro.magnet.fsu.edu/
energy level.
Current Atomic Model:
Schrodinger Model
Electrons do not travel in fixed paths
around the nucleus
Electrons constantly move to different
energy levels in the electron cloud.
Direction of movement is dependent
upon how much energy an electron
has.
Observed several different paths
electrons can take around the
nucleus.
Electron Movement
1.
2.
3.
1. Ground state of H Atom (lowest energy level for e-)
2. A photon (light particle) is absorbed by H’s electron.
Electron becomes excited and jumps to higher energy level.
3. E- returns to ground state and emits (releases) the photon.
Emitted photon’s wavelength can be detected by scientists.
(Infrared region at room temp; Visble region at higher temps.)
Electromagnetic Radiation Spectrum
a. Relationship b/w wavelength and frequency?
b/w wavelength and energy emission?
b. Relationship
c. Relationship b/w frequency and energy emission?
Orbital Shapes
A maximum of 2 electrons can move in each orbital.
Periodict Table: Electron Configuration
Atomic Properties
If most of the atom is empty space, why doesn’t
matter pass through one another?
spiff.rit.edu
Chem II: 8/19/13
Objectives:
• Review and assess Chem I
Homework:
Chemical Reaction review wksht.
Chem II: Bell Ringer
1. Classify the following as a substance or a mixture.
a. HCl(l)
b. HCl(aq) c. iron statue d.marble statue
2. How many significant figures are in each
measurement below:
a. 0.0050 g. b.3,020g c. 8.060g d. 1.00x104 g
3. Record answer to the correct number of sig. figs.
a. 4.050 g x 0.0250 g =
b. 2.85 cm + 0.302cm + 18cm =
4. b. Write the electron configuration of the following
atoms: O, Ar, Cu2+, Br1c. Cirlce the atoms above that are stable.
5. Identify the two types of forces in an atom.
Chem II: Bell Ringer
8. What is an isotope?
9. What is the difference between mass number
and atomic mass for an atom?
10. Classify each element as transitional or
representative. Na, Fe, Pb, Ar, Ag
11. Define the following periodic trends:
atomic radius, ionization energy, and
electronegativity.
Chem II: Bell Ringer
1. Classify the following as a substance or a mixture.
a. HCl(l)
b. HCl(aq) c. iron statue d.marble statue
2. How many significant figures are in each
measurement below:
a. 0.0050 g. b.3,020g c. 8.060g d. 1.00x104 g
3. Record answer to the correct number of sig. figs.
a. 4.050 g x 0.0250 g =
b. 2.85 cm + 0.302cm + 18cm =
4. Write the electron configuration of the following
atoms: O, Ar, Cu2+, Br1c. Cirlce the atoms above that are stable.
5. Identify the two types of forces in an atom.
Classification of Matter
Periodict Table: Electron Configuration
Atomic Forces
• Electrostatic Forces :
- Forces between charged
particles.
Types of electrostatic forces:
a. Attractive: (p+ and e-)
b. Repulsion: (p+ and p+
e- and e-)
• Nuclear Forces:
Forces that holds p+ and n0
together in nucleus.
6.Classify each change as chemical or physical
a. combustion b. sublimation c. dissolves d. rusted
7. Changes in
state
of matter
evaporation of
water
condensation
of alcohol
deposition of
copper
Kinetic Energy:
Absorbed or Released
by molecules/atoms?
Intermolecular Forces:
Strengthened or
Weakened
What kind of forces are affected ?
.
Energy Changes
a.
b.
Chem II: Bell Ringer
8. What is an isotope?
9. What is the difference between mass number
and atomic mass for an atom?
10. Classify each element as transitional or
repsentative. Na, Fe, Pb, Ar, Ag
11. Define the following periodic trends:
atomic radius, ionization energy, and
electronegativity.
Isotopes
• Isotopes= atoms of the same element
with different number of neutrons.
• Elements can have several isotopes.
C-12
C-13
C-14
Mass Number vs. Atomic Mass
Mass Number:
• The mass of an individual atom.
• Sum of protons and neutrons in an atom.
Atomic Mass:
• Average mass of an element.
• Calculated by the number of isotopes an
element has.
• Mass on periodic table.
Atomic Structure
Subatomic symbol
Particle
charg Mass (g)
e
mass
(amu)
proton
p+
+1
1.674 x 10 -24
1
electron
e-
-1
9.11 x 10-28
0
neutron
n0
0
1.675 x 10 -24
1
Chem II: Bell Ringer
8. What is an isotope?
9. What is the difference between mass number
and atomic mass for an atom?
10. Classify each element as transitional or
repsentative. Na, Fe, Pb, Ar, Ag
11. Define the following periodic trends:
atomic radius, ionization energy, and
electronegativity.
Periodic Trends: Atomic Radius
Atomic Number vs. Atomic
Radius
Across a Period
200
Down a Group
atomic raidus (pm)
180
160
140
120
100
80
60
40
20
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
atomic number
15
16
17
18
Periodic Trends: Ionization
Energy
Atomic Number vs. Ionization Energy
Across a Period:
Ionization Energy (kJ/mol)
Down a Group:
2500
2000
1500
1000
500
0
1
3
5
7
9
11
Atomic Number
13
15
17
Periodic Trend: Electronegativity
Across a Period:
Down a Group:
mmsphyschem.com
Electronegativity
Periodic Table:
Trends/Organization
Chem II: 8/20/13
Objectives:
• Review chemical bonding and nomenclature.
• Classify and balance chemical equations.
• Stoichiometry and Limiting Reactants.
Homework:
• Chemical reaction and stoichiometry wksht.
Chemical Bonding: Classification
Distinguish between ionic and covalent cmpds.
Covalent
Ionic
Similarities
Chemical Compounds
Chemical Name
Chemical
Formula
BaCl2
CO2
Fe(OH)3
oxgen
nitrogen trihydride
lead (II) sulfate
Ionic or
Covalent Cmpd.
Acids vs. Bases: Nomenclature
Classify as acidic or basic, then name or establish
the chemical formula.
•
•
•
•
•
•
•
•
Na(OH): base, sodium hydroxide
Cr(OH)2: base, chromium (II) hydroxide
H2S: hydrosulfuric acid
H2(SO3): sulfurous acid
H2(SO4): sulfuric acid
carbonic acid: H2(CO3)
hydrofluoric acid: HF
phosphorous acid: H3(PO3)
Chemical Bonding: Classification
Ionic Bonding:
• Transfer of valence electrons between two atoms.
(different electronegativity values)
• Commonly between a metal and a nonmetal.
• Could contain a polyatomic ion.
Covalent Bonding
• Sharing of valence electrons between two atoms.
(similar electronegativity values)
• Commonly between non-metal atoms.
(similar electronegativity values)
• Also called molecules.
Chemical Bonding and Electronegativity
Molecules and Polarity
Polar Molecules: Do not share electrons equally.
Ex. O----H (between different non-metals)
Non-Polar Molecules: Share electrons equally.
Ex. H-----H (Diatomic molecules. )
Acids vs. Bases
Acids vs. Bases: Nomenclature
•
•
•
•
•
Na(OH)= sodium hydroxide
Cr(OH)2 = chromium (II) hydroxide
H2S= hydrosulfuric acid
H2(SO3)= sulfurous acid
H2(SO4)= sulfuric acid
Type of Anion
Name of Acid
Monatomic anion
(-ide ending)
hydro + stem + ic
Polyatomic anion
(-ite ending)
stem + ous
Polyatomic anion
(-ate ending)
stem + ic
Chem II: 8/21/13
Objectives:
• Review Word Equation Worksheet
• Quiz on naming and classifying compounds
• Review stoichiometry and limiting reagents.
Homework:
• Stoichiometry packet
Word Equation Worksheet
Chem II: 8/22/13
Objectives:
• Review Chemical Naming Quiz
• Review stoichiometry and limiting reagents.
Homework:
• Chemial Naming and Stoichiometry packet
• Quiz tomorrow
Chemical Compounds
Types of Chemical Reactions
1. Synthesis
(A+ B ----> AB)
2. Decomposition (AB------> A + B)
3. Single Replacement (A+ BC ---> B + AC)
4. Double Replacement (AB + CD ---> CB + AD)
5. Combustion (CxHx + O2 ----> CO2 + H2O)
6. Neutralization (Acid + Base--> H2O + Salt)
N2
Stoichiometry
+
3H
---------->
2
2NH3
Stoichiometry:
•Converting between substances in a balanced
chemical equation using mole conversions.
www.larapedia.com
Stoichiometry
1. HgO (s) ------------> Hg(l) + O2 (g)
a. Balance the equation if needed.
b. If two moles of mercury are needed from the
experiment, how many moles of mercury (II)
oxide are needed?
c. If 5.4 grams of HgO is heated, how many
grams of mercury and oxygen can be
produced in this chemical reaction?
Stoichiometry
1. 2HgO (s) ------------> 2Hg(l) + O2 (g)
a. Balance the equation if needed.
b. If two moles of mercury are needed from the
experiment, how many moles of mercury (II)
oxide are needed?
Chem II: 8/23/13
Objectives:
• Complete Chem I Review Quiz
• I can convert between substances in a
chemical equation using stoichiometry.
• I can identify and apply limiting reactants
in chemical reactions.
• I can calculate percent yield of product.
Homework:
• Read and complete pre-lab questions for
stoichiometry lab.
Stoichiometry
1. 2HgO (s) ------------> 2Hg(l) + O2 (g)
c. If 5.4 grams of HgO is heated, how many
grams of mercury and oxygen can be
produced in this chemical reaction?
Stoichiometry
Stoichiometry: Limiting
Reactants
• Limiting Reactant: completely consumed
• Excess Reactant: partially consumed
en.wikipedia.org
Stoichiometry: Limiting Reactant
HCl + Mg ------->
MgCl2 + H2
1. What type of reactions is this?
2. Balance equation if needed.
3. If 6.8 moles of Mg react with 7.5 moles of HCl which is
considered the limiting reactant? excess reactant?
Reactants
Have (moles)
Need (moles)
Stoichiometry: Limiting Reactant
2HCl + Mg -------> MgCl2 + H2
1.If 6.8 moles of Mg react with 7.5 moles of HCl
how many moles of MgCl2 can be produced?
Reactants
Have (moles) Need (moles)
HCl (limited)
7.5 mol
13.6 (limited)
Mg (excess)
6.8 mol
3.75 (excess)
Chem II: 8/26/13
Objectives:
• Self-assess Chem II Quiz
• I can identify and apply limiting reactants in
chemical reactions.
• I can calculate percent yield of product.
• Introduce Stoichiometry Lab
• Gallery Walk: Chem I review
Homework:
• Read and complete pre-lab questions for
stoichiometry lab. (Lab Tuesday)
• Study for Chem I Review Test (Wed.)
Stoichiometry: Percent Yield
% Yield of Product:
Accuracy of product formation in the lab.
% Yield of product:
actual yield
x 100
theoretical yield
Actual yield: actual amount produced in the lab
Theoretical yield: maximum amount that can be
produced according to the limiting reactant.
(calculated yield)
Stoichiometry: Limiting Reactant
2HCl + Mg -------> MgCl2 + H2
1.If 6.8 moles of Mg react with 7.5 moles of HCl
how many moles of MgCl2 can be produced?
Reactants
Have (moles) Need (moles)
HCl (limited)
7.5 mol
13.6 (limited)
Mg (excess)
6.8 mol
3.75 (excess)
Stoichiometry and Limiting Reactant
3. Sulfuric acid reacts with aluminum hydroxide
by double replacement.
Chem II: 8/27/13
Objectives:
• Identify and apply limiting reactants in
chemical reactions.
• Calculate percent yield of products.
• Address Chem I quiz
• Chem I Gallery Walk
Homework:
• Stoichiometry Lab (Wed.)
• Chem I Exam (Thurs.)
Stoichiometry: Limiting Reactants
1. Balance Chemical Equation
2. Create reactants table to compare have to
need of each reactant ( units: moles or grams).
3. Identify the limiting and excess reactant.
4. Use limiting reactant to calculate theoretical
yield of each product.
5. Calculate percent yield by comparing actual
yield (from lab) to theoretical yield (calculate).
Stoichiometry and Limiting Reactant
3. 3H2(SO4) + 2Al(OH)3 ---> Al2(SO4)3 + 6H2O
Reactants
Sulfuric Acid
Aluminum Hydroxide
Have (moles)
Need (moles)
Stoichiometry and Limiting Reactant
3. 3H2(SO4) + 2Al(OH)3 ---> Al2(SO4)3 + 6H2O
Reactants
Have (moles)
Sulfuric acid
0.306 moles
Aluminum hydroxide 0.321 moles
Need (moles)
0.482
0.204
Chem I Review Quiz
Stoichiometry Lab
Homework:
• Read thru lab and complete pre-lab questions.
(requirement for lab).
Chem II: 8/28/13
Objectives:
• Assess a limiting reactant problem.
• Complete Stoichiometry Lab
Infinite Campus Update:
• Stoichiometry problem (6pts)
• Limiting and % Yield problem (10pts.)
Homework:
• Stoichiometry Lab: post-lab section
• Chem I review exam
(review session after school if needed)
Limiting Reactant and % Yield Assessment
Review Practice Problems:
15a. Reactants
Have (mols)
Need (mols)
Pb(NO3)2
0.082
0.28 (limiting)
NaI
0.55
0.16 (excess)
b.Using what I have of Pb(NO3)2, the theoretical
yield of PbI2 = 37.8 g
c. Left-over of excess reactant:
(left over = have – need of excess reactant)
0.55 mol – 0.16 mol = 0.39 mol  58.5 g NaI
d. %Y = ( AY/TY)x100 : actual yieldPbI2 = 36.54 g;
theoretical yield PbI2 =37.8g
%Y = 96.7% yield of PbI
Stoichiometry Lab
• Purpose: Apply limiting reactant and percent
yield calculations in the lab.
• Hypothesis: Predict how much NaCl you will
produce in the lab today. (Record hypothesis
under pre-lab section.)
Experiment:
• Follow instructions carefully.
• Must wear goggles at all times.
• Record all data (qualitative and quantitative)on
notebook paper.
Chem II: 8/28/13
Homework:
• Stoichiometry Lab: post-lab section
• Chem I review exam
(review session after school if needed)
Gallery Walk
• Chem I review problems for exam on Thursday.