Chem II: 8/15/13 Objectives: Distribute Textbooks Address Graduate Cylinder Lab Review Pre-Assessment Test Gallery Walk Review Introduce Stoichiometry.

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 FiguresSignificant 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 Englishk h dk base d c ma. 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 make-up from sample to sample.• 2 or more substances physically combined•Homo or Hetero Mixtures• Pizza and salt water

Elements•Smallest type of matter that maintains it properties.

•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.

• Each compound has a unique chemical formula.

Ex. Sodium chloride = NaCl

•The chemical combination of substances produces new

properties.

Sodium (Na) + Chlorine (Cl) = Salt (NaCl)

Heterogenous MixuresObserve multiple phases (parts) because the substances do not mix well. Substances have a low solubility for one another.

Homogenous MixturesSubstances 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 + H2

O

Chemical vs. Physical ChangeChemical 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

H2O compound

Forces within a single compound that holds the atoms together. Also called chemical

bonds.

Types of Chemical Changes• Combustion

• Decaying

• Digesting

• Baking

• Neutralization (acidic and basic chemicals)

• Growing

• Spoiled

Intermolecular ForcesForces 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

Visionlearning.com

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

Molecular Kinetic Theory:Establishes a relationship between energy flow, speed of

particles, and intermolecular forces during physical changes.

Changes in state of matter

Kinetic Energy:Absorbed or Released

Intermolecular Forces:Strengthened orWeakened

evaporation of water

condensationof alcohol

deposition of copper

melting of ice cream

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

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.

Dalton’s Atomic Theory

Thomson’s Cathode Tube Experiment

l-esperimento-piu-bello-della-fisica.bo.imm.c...

Discovered negatively charged particles in different gases through this experiment.

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)

•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.

Subatomic Particle: Neutron

Bohr’s Model of the Atom

http://micro.magnet.fsu.edu/

•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 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. 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.)

1. 2. 3.

Electromagnetic Radiation Spectrum

a. Relationship b/w wavelength and frequency?

b.Relationship b/w wavelength and energy emission?

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 PropertiesIf 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 Ringer1. 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+, Br1-

c. Cirlce the atoms above that are stable.

5. Identify the two types of forces in an atom.

Chem II: Bell Ringer8. 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 Ringer1. 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+, Br1-

c. 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.

7. Changes in state of matter

Kinetic Energy:Absorbed or Released by molecules/atoms?

Intermolecular Forces:Strengthened orWeakened

evaporation of water

condensationof alcohol

deposition of copper

6.Classify each change as chemical or physicala. combustion b. sublimation c. dissolves d. rusted

What kind of forces are affected ?

.

Energy Changes

a. b.

Chem II: Bell Ringer8. 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 MassMass 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 StructureSubatomic Particle

symbol charge

Mass (g)

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 Ringer8. 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

Across a Period

Down a Group

Periodic Trends: Ionization Energy

Across a Period:

Down a Group:

Periodic Trend: Electronegativity

mmsphyschem.com

Across a Period:

Down a Group:

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: ClassificationDistinguish between ionic and covalent cmpds.

Ionic Covalent

Similarities

Chemical Compounds Chemical Name Chemical

FormulaIonic or Covalent Cmpd.

BaCl2

CO2

Fe(OH)3

oxgen

nitrogen trihydride

lead (II) sulfate

Acids vs. Bases: Nomenclature

• 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)

Classify as acidic or basic, then name or establish the chemical formula.

Chemical Bonding: ClassificationIonic 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 PolarityPolar 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)

Stoichiometry N2 + 3H2 ----------> 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: 8/23/13Objectives:

• 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: 8/26/13Objectives:

• 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 Reactant3. Sulfuric acid reacts with aluminum hydroxide

by double replacement.

Chem II: 8/27/13Objectives:

• 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 Reactants1. 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 Reactant3. 3H2(SO4) + 2Al(OH)3 ---> Al2(SO4)3 + 6H2O

Reactants Have (moles) Need (moles)

Sulfuric AcidAluminum Hydroxide

Stoichiometry and Limiting Reactant3. 3H2(SO4) + 2Al(OH)3 ---> Al2(SO4)3 + 6H2O

Reactants Have (moles) Need (moles)

Sulfuric acid 0.306 moles 0.482Aluminum hydroxide 0.321 moles 0.204

Chem I Review Quiz

Stoichiometry LabHomework:

• Read thru lab and complete pre-lab questions. (requirement for lab).

Chem II: 8/28/13Objectives:

• 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 AssessmentReview 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 PbI2

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.