Advanced Chemistry Bell Ringers Quarter 2. Bell Ringer 11-2-15 How many valence electrons are in...

Advanced ChemistryBell Ringers

Quarter 2

Bell Ringer 11-2-15How many valence electrons are in each of these

atoms or ions? Xe, Sr2+, Cl, and Cl–

Exit Closing 11-2-15Draw Lewis structures for the following molecular compounds and ions: (a) AlCl3, (b) PH3; (c) H2Se;

(d) NO2–; (e) AlH4

–.

Bell Ringer 11-3-15How do the electronegativities of the elements change across a row and down a group in the

periodic table?

Exit Closing 11-3-15

Which is the least polar bond? C—Se C==O Cl—Br O==O N—H C—H

Bell Ringer 11-4-15

What factors determine whether or not a molecule or ion exhibits resonance?


Oxygen and sulfur combine to form a variety of different sulfur oxides. Some are stable molecules and some, including S2O2 and S2O3,

decompose when they are heated. Draw Lewis structures for the two compounds showing all resonance forms.

Bell Ringer 11-5-15

How do the electronegativities of elements influence the selection of which Lewis structure is favored?


Origins of Life The discovery of polyatomic organic molecules such as cyanamide (H2NCN) in interstellar space has led some scientists to

believe that the molecules from which life began on Earth may have come from space. Draw Lewis structures for cyanamide, and select the

preferred structure on the basis of formal charges.

Bell Ringer 11-6-15

In which of the following molecules does the phosphorus atom have an expanded valence shell? (a) POCl3; (b) PF5; (c) PF3; (d) P2F4 (which has a

P P bond)


Which of the following nitrogen oxides are odd-electron molecules?

(a) NO; (b) NO2; (c) NO3; (d) N2O4; (e) N2O5

Bell Ringer 11-9-15

Rank the following ions in order of increasing carbon–oxygen bond lengths:

CO, CO2, and CO32–.


Rank the following ions in order of increasing carbon–oxygen bond energy:

CO, CO2, and CO32–.

Bell Ringer 11/10/15

Chapters 3 & 4 Exam

Pick up your remote from the CPS bag. Be sure that it is YOUR number. Begin testing immediately.

You may use: Scratch paper and a NON-Programmable Calculator. No Cell Phones!

Exit Closing 11/10/15We will entertain 3 questions or comments before we leave today. You have one minute to write down one

question that you should be prepared to share.


Day 1 of 4 Foundry Lab (In the Library Days 1 & 4)

Your lab notebook should focus on Short Intro with prediction, procedures, Safety, and Data

Formal Write Up Should Include:Intro (last sentence is prediction), Procedures, Safety, Data & Observations, Calculations & Results (excel graphs et), Discussion of Results, References in ACS and Additional Questions


Day 2 of 4 Foundry Lab Data Collection Day!




Day 3 of 4 Foundry Lab Data Collection Day!




Day 4 of 4 Foundry Lab (In the Library Days 1 & 4)




In which molecular geometry do equatorial bonding pairs of electrons repel each other more: square pyramidal or trigonal bipyramidal?

Exit Closing 11/17/15

The O–N–O bond angle in NO2 is slightly larger than it is in NO2–. Why?


Rank the following molecules in order of increasing bond angles: (a) NH3; (b) CH4; (c) H2O.


Determine the molecular geometries of the

following molecules and ions:

(a) NO3–

(b) NO43–

(c) NCN2–

(d) NF3.


Determine the molecular geometries of the following ions: (a) SCN–; (b) CH3PCl3

+ (P is the central atom and is bonded to the C atom of the methyl group); (c) ICl2

–; (d) PO33–.


Which two of the species N3–, O3, and CO2 have the same molecular geometry?


Must a polar molecule contain polar covalent bonds? Why?


Which of the following molecules has a permanent dipole? (a) C4F8 (cyclic structure); (b) ClFCCF2; (c) Cl2HCCClF2


Which molecule in each of the following pairs is more polar? (a) NH3 or PH3; (b) CCl2F2 or CBr2F2


What is the hybridization of nitrogen in each of the following ions and molecules? (a) NO2

+; (b) NO2–; (c) N2O; (d) N2O5; (e) N2O3


How does the hybridization of the sulfur atom change in the series SF2, SF4, SF6?


What is the molecular geometry around sulfur and nitrogen in the sulfamate anion shown in Figure P5.73? Which atomic or hybrid

orbitals overlap to form the S–O and S–N bonds in the sulfamate anion?


Which of the molecules in Figure P5.82 are chiral?


Which of the molecules in Figure P5.84 are chiral?

Bell Ringer 12/1/15

Do all σ molecular orbitals result from the overlap of s atomic orbitals?


Do all π molecular orbitals result from the overlap of p atomic orbitals?

Bell Ringer 12/2/15

Diatomic noble gas molecules, such as He2 and Ne2, do not exist. Would removing an electron create molecular ions, such as He2

+ and Ne2+, that

are more stable than He2 and Ne2?


Which of the following molecular ions are diamagnetic? (a) O2–; (b) O2

2–; (c) N2

2–; (d) F2+

Bell Ringer 12/3/15

Which of the following molecular cations have electrons in π antibonding orbitals? (a) N2

+; (b) O2+; (c) C2

2+; (d) Br22+


For which of the following diatomic molecules does the bond order increase with the loss of two electrons, forming the corresponding 2+

cation? (a) B2; (b) C2; (c) N2; (d) O2

Bell Ringer 12/4/15

Cl2O2 may play a role in ozone depletion in the stratosphere. Draw the Lewis structure for Cl2O2 based on the skeletal structure in Figure P5.110. What is the geometry about the central chlorine atom?


Ozone Depletion In 1999, the ClO+ ion, a potential contributor to stratospheric ozone depletion, was

isolated in the laboratory.a. Draw the Lewis structure for ClO+. b. Using the molecular orbital diagram for ClO+

in Figure P5.113, determine the order of the Cl–O bond in ClO+.

Bell Ringer 12/7/15

Early Earth Some scientists believe that an anion with the skeletal structure shown in Figure P5.114 may have played a role in the

formation of nucleic acids before life existed on Earth. a. Complete the Lewis structure of this anion.b. Predict the C—P—O bond angle in the anion.


Two compounds formed by the reaction of boron with carbon monoxide have these skeletal structures: B–B–C–O and O–C–B–B–C–O.a. Draw the Lewis structures of both compounds that minimize formal charges. b. What are the B–B–C bond angles in the molecules?

Bell Ringer 12/8/15

The three most abundant gases in air are N2, O2, and Ar. Which of them has the highest boiling point, and which has the lowest boiling point?


How are water molecules oriented around cations in aqueous solutions?

Bell Ringer 12/9/15

Why is the boiling point of Br2 lower than that of iodine monochloride, ICl, even though they have nearly the same molar mass?


Molecules of which of these compounds: CO2, NO2, SO2, or H2S, experience dipole–dipole interactions?


In an aqueous solution containing Na+, Mg2+, K+, and Ca2+ salts, which cation would you expect to experience the strongest ion–dipole

interactions?


In each of the following pairs of compounds, which compound is likely to be

more soluble in CCl4?

a. Br2 or NaBr

b. CH3CH2OH or CH3OCH3

c. CS2 or KOH

d. I2 or CaF2


Rank the ketones in Figure P6.40 from least soluble to most soluble in water.


Below what temperature can solid CO2 (dry ice) be converted into CO2 gas simply by lowering the pressure?


A hot needle sinks when placed on the surface of cold water, but a cold needle floats. Why?


The mercury level in a capillary tube inserted into a dish of mercury is below the surface of the mercury in the dish. Why?


Chapters 5 & 6 Exam


You may use: Scratch paper, Periodic Table and a NON-Programmable Calculator. No Cell Phones!

Bell Ringer 12-16-15

Write a balanced chemical equation for each of the following reactions:a. Carbon dioxide reacts with carbon to form carbon monoxide.b. Potassium reacts with water to give potassium hydroxide and the element hydrogen.

c. Phosphorus (P4) burns in air to give diphosphorus pentoxide.


Charcoal (C) and propane (C3H8) are used as fuel in backyard grills.a. Write balanced chemical equations for the complete combustion

reactions of C and C3H8.b. How many grams of carbon dioxide are produced from burning 500.0 grams of each of the two fuels?


Lead Compounds as Pigments Ancient Egyptians used lead compounds including PbS, PbCO3, and Pb2Cl2CO3 as pigments in cosmetics, and many people suffered from

chronic lead poisoning as a result. Calculate the percentage of lead in each of the compounds.


A sample of an iron-containing compound is 22.0% iron, 50.2% oxygen, and 27.8% chlorine by mass. What

is the empirical formula of this compound?


Ferrophosphorus (Fe2P) reacts with pyrite (FeS2), producing iron(II) sulfide and a compound that is

27.87% P and 72.13% S by mass and has a molar mass of 444.56 g/mol.

a. Determine the empirical and molecular formulas of the compound. b. Write a balanced chemical equation for the reaction.


A reaction vessel contains 10.0 g CO and 10.0 g O2 which combine to form CO2:

2 CO(g) + O2(g) → 2 CO2(g)

a. Which reactant is the limiting reactant?b. How many grams of CO2 could be produced?c. How many grams of the nonlimiting reactant are left over?

Bell Ringer 1-4-16

Calculate the molarity of each of the following solutions:a. 0.150 mol urea [(NH2)2CO] in 250.0 mL of solution

b. 1.46 mol NH4CH3CO2 in 1.000 L of solution

c. 1.94 mol methanol (CH3OH) in 5.000 L of solution

d. 0.045 mol sucrose (C12H22O11) in 50.0 mL of solution

Exit Closing 1-4-16

Chemists who analyze samples for dissolved trace elements may buy standard solutions that contain

1.000 g/L concentrations of the elements. If a chemist wishes to prepare 0.500 L of a working standard that has a concentration of 5.00 mg/L, what volume of the

1.000 g/L standard is needed?

Bell Ringer 1-5-16

What is the molarity of each ion in a 0.025 M aqueous solution of (a) KCl; (b) CuSO4; (c) CaCl2?

Exit Closing 1-5-16

Write a balanced molecular equation and a net ionic equation for the following reactions:

a. Solid aluminum hydroxide reacts with a solution of hydrobromic acid.b. A solution of sulfuric acid reacts with solid sodium carbonate.c. A solution of calcium hydroxide reacts with a solution of nitric acid.

Bell Ringer 1-6-16

Given the following equation, how many grams of PbCO3 will dissolve when 1.00 L of 1.00 M H+ is added

to 5.00 g of PbCO3?

PbCO3(s) + 2 H+(aq) → Pb2+(aq) + H2O(ℓ) + CO2(g)

Exit Closing 1-6-16

How many milliliters of 0.100 M HNO3 are needed to neutralize the following solutions?

a. 45.0 mL of 0.667 M KOHb. 58.5 mL of 0.0100 M Al(OH)3

c. 34.7 mL of 0.775 M NaOH

Bell Ringer 1-7-16

An expanding gas does 150.0 J of work on its surroundings at a constant pressure of 1.01 atm. If the

gas initially occupied 68 mL, what is the final volume of the gas?

Exit Closing 1-7-16

Calculate ∆E for a system that absorbs 726 kJ of heat from its surroundings and does 526

kJ of work on its surroundings.

Bell Ringer 1-8-16

The same quantity of thermal energy is added to equal masses of four metals:

titanium, iron, silver, and lead. All of them are initially at the same temperature. Which

metal has the highest final temperature?

Exit Closing 1-8-16

A 20.0 g piece of iron and a 20.0 g piece of gold at 100.0°C are dropped into 1.00 L of water at

20.0°C. What is the final temperature of the water and pieces of metal?

Bell Ringer 1-11-16

Calculate the heat capacity of a calorimeter if the combustion of 4.663 g of benzoic acid produces an increase in

temperature of 7.149°C.


Ozone Layer The destruction of the ozone layer by chlorofluorocarbons (CFCs) can be described by the following reactions:

ClO(g) + O3(g) → Cl(g) + 2 O2(g) ∆H°rxn = –29.90 kJ

2 O3(g) → 3 O2(g) ∆H°rxn = +24.18 kJ

Use the above ∆H°rxn values to determine the value of the standard heat of reaction for this reaction:

Cl(g) + O3(g) → ClO(g) + O2(g) ∆H°rxn = ?

Bell Ringer 1-12-16

No Time To Spare!!!ACS Review Day Atomic Structure

Bell Ringer 1-13-16

No Time To Spare!!!ACS Review Day

Molecular Structure & Bonding

Bell Ringer 1-14-16


Stoichiometry

Bell Ringer 1-15-16

No Time To Spare!!!ACS Review Day States of Matter

Bell Ringer 1-19-16


Energetics


Advanced Chemistry Final Exam



Bell Ringer 1-22-16

At an elevation where the boiling point of water is 93°C, 1.33 kg of water at 30°C absorbs 290.0 kJ from a mountain climber’s stove. Is this amount of thermal

energy sufficient to heat the water to its boiling point?

Bell Ringer 1-25-16

Use the information in the following two thermochemical equations:

NO2Cl(g) → NO2(g) + 1/2 Cl2(g) ∆H°rxn = –114 kJ1/2 N2(g) + O2(g) → NO2(g) ∆H°rxn = +33.2 kJ

to calculate the value of ∆H°rxn for this reaction:1/2 N2(g) + O2(g) + 1/2 Cl2(g) → NO2Cl(g) ∆H°rxn = ?


For which of the following reactions does ∆H°rxn also represent a heat of formation?a. 2 N2(g) + 3 O2(g) → 2 NO2(g) + 2 NO(g)

b. N2(g) + O2(g) → 2 NO(g)

c. 2 NO2(g) → N2O4(g)

d. N2(g) + 2 O2(g) → 2 NO2(g)

Bell Ringer 1-26-16

Take out your take home essay quizzes…

Which question is your most difficult and which is the easiest?

Which question is the most difficult to write about and which is the easiest?

Bell Ringer 1/27/16

Chapters 7, 8, & 9 Exam



Advanced Chemistry Bell Ringers Quarter 2. Bell Ringer 11-2-15 How many valence electrons are in...

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