Search found 50 matches

by Nhi Vo 3A
Mon Mar 13, 2017 5:22 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Increasing Standard Molar Entropy
Replies: 1
Views: 444

Increasing Standard Molar Entropy

Arrange the following substances in order of increasing standard molar entropy:
CHF3(g), CF4(g), CH3F(g), CH2F2(g)

The answer was CH3F (g) < CH2F2 (g) < CHF3 (g) < CF4 (g), but I don't understand why CF4 was placed last while CH3F is placed first. Is molar entropy not based on polarity?
by Nhi Vo 3A
Mon Mar 13, 2017 9:41 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram and Pt(s)
Replies: 4
Views: 512

Cell Diagram and Pt(s)

How do we know when to add the Pt(s) in our cell diagrams?
by Nhi Vo 3A
Fri Mar 10, 2017 12:54 pm
Forum: *Nucleophilic Substitution
Topic: Electrophilic Aromatic Substitution
Replies: 1
Views: 576

Electrophilic Aromatic Substitution

I was wondering if electrophilic aromatic substitution and nucleophilic substitution reaction were similar or how are they different from each other?
by Nhi Vo 3A
Thu Mar 02, 2017 2:47 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate Determining Step
Replies: 1
Views: 252

Rate Determining Step

If given a proposed mechanism and the rate, how can you tell which step in the mechanism is likely to be the rate determining step?
by Nhi Vo 3A
Mon Feb 27, 2017 11:39 pm
Forum: *Alkanes
Topic: Name the compound
Replies: 4
Views: 386

Name the compound

(CH3)2CHCH(CH2CH3)2

I get confuse when the compound is written like this. If possible, can you draw its line structure please. Thank you
by Nhi Vo 3A
Sat Feb 25, 2017 10:28 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: What is the catalyst in this reaction? [ENDORSED]
Replies: 2
Views: 751

What is the catalyst in this reaction? [ENDORSED]

Step 1: O3 + NO --> NO2 + O2
Step 2: NO2 + O --> NO + O2

What is the catalyst in this reaction? How can you tell?
by Nhi Vo 3A
Fri Feb 17, 2017 11:43 am
Forum: General Rate Laws
Topic: Overall Rate Law from Proposed Mechanism
Replies: 1
Views: 240

Overall Rate Law from Proposed Mechanism

The proposed two step mechanism for a reaction is H2AH2A + B --> BH^+ + HA^- and its reverse, both of which are fast, followed by HA^- + B --> BH ^+ + A^2-, which is slow.

Find the rate law with HA^- treated as the intermediate and write the equation for the overall reaction.
by Nhi Vo 3A
Tue Feb 07, 2017 11:50 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Calculating the change in molar entropy
Replies: 1
Views: 249

Calculating the change in molar entropy

Calculate the change in molar entropy of an ideal gas when it is compressed isothermally to 1/3 its initial volume.
by Nhi Vo 3A
Sat Feb 04, 2017 10:05 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: calculating reaction Gibbs free energy
Replies: 1
Views: 177

calculating reaction Gibbs free energy

The reaction taking place in the silver cell used in some cameras and wristwatches in Ag2O(s) + Zn(s) --> 2Ag(s) + ZnO(s), and the cell potential when new is +1.6V. What is the reaction Gibbs free energy?
by Nhi Vo 3A
Wed Jan 25, 2017 2:27 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Calculating Energy Changes When Heating an Ideal Gas
Replies: 1
Views: 237

Calculating Energy Changes When Heating an Ideal Gas

Calculate the final temperature and the change in internal energy when 500. J of energy is transferred as heat to 0.900 mol Ne (g) at 298 K and 1.00 atm
a) at constant volume
b) at constant pressure
Treat the gas as ideal.
by Nhi Vo 3A
Wed Jan 25, 2017 1:45 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Calculate work and internal energy
Replies: 1
Views: 247

Calculate work and internal energy

Suppose that 1.00 kJ of energy is transferred as heat to oxygen in a cylinder fitted with a piston; the external pressure is 2.00 atm. The oxygen expands from 1.00 L to 3.00 L against this constant pressure. Calculate w and internal energy (delta U) for the entire process by treating the O2 as an id...
by Nhi Vo 3A
Wed Jan 25, 2017 12:58 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Calculating Internal Energy Change
Replies: 1
Views: 254

Calculating Internal Energy Change

A calorimeter was calibrated by mixing two aqueous solutions together, each of volume 0.100L. The heat output of the reaction that took place was known to be 4.16kJ, and the temperature of the calorimeter rose by 3.24 degrees C. Calculate the heat capacity of this calorimeter when it contains 0.200 ...
by Nhi Vo 3A
Fri Jan 20, 2017 2:10 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Calculating work of isothermal expansion [ENDORSED]
Replies: 1
Views: 290

Calculating work of isothermal expansion [ENDORSED]

A cylinder of volume 2.00 L contains 1.00 mol He (g) immersed in a constant-temperature water bath held at 30 degrees Celsius. Which process does more work on the surroundings, allowing the gas to expand isothermally to 4.00 L against a constant external pressure of 1.00 atm or allowing it to expand...
by Nhi Vo 3A
Fri Dec 02, 2016 1:02 pm
Forum: Trends in The Periodic Table
Topic: Which is larger O - or S 2- ? [ENDORSED]
Replies: 3
Views: 520

Which is larger O - or S 2- ? [ENDORSED]

Which anion is larger O ^- or S ^ 2- ?

Give two reasons why.
by Nhi Vo 3A
Fri Dec 02, 2016 12:59 pm
Forum: Quantum Numbers and The H-Atom
Topic: Midterm Q.5B
Replies: 2
Views: 378

Midterm Q.5B

What is the subshell notation and the total number of orbitals having the quantum numbers n=3, l=2, for a given element?

I got subshell notation to be 3d and total number of orbitals to be 10, why is this wrong?
by Nhi Vo 3A
Fri Dec 02, 2016 12:46 pm
Forum: Photoelectric Effect
Topic: Midterm 3B
Replies: 1
Views: 305

Midterm 3B

The photoelectric experiment became known as the photoelectric effect. What was the major conceptual change as a result of this experiment?
by Nhi Vo 3A
Wed Nov 16, 2016 10:54 pm
Forum: Naming
Topic: What's the formula for this coordination compound?
Replies: 2
Views: 1186

What's the formula for this coordination compound?

Dibromobis(ethylenediamine)cobalt(III)sulfate
by Nhi Vo 3A
Mon Nov 07, 2016 9:11 pm
Forum: Naming
Topic: Name this compound
Replies: 1
Views: 558

Name this compound

From textbook self test 17.3B: Name the compound [CoBr(NH3)5]SO4

Write the formula of tetraamminediaquachromium(III)bromide

Thank you!
by Nhi Vo 3A
Fri Nov 04, 2016 10:14 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: 4.61 Homework Question
Replies: 3
Views: 421

4.61 Homework Question

Give the valence-shell electron configurations and bond orders for CO and CO+. Which has a stronger bond?
by Nhi Vo 3A
Sat Oct 29, 2016 12:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Can you present VSEPR theory without having to deal with Lewis Structures?
Replies: 1
Views: 236

Can you present VSEPR theory without having to deal with Lewis Structures?

Is there a way to present VSEPR theory without having to deal with Lewis structures?
by Nhi Vo 3A
Sat Oct 29, 2016 12:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: What would be the shape of Ethyne?
Replies: 1
Views: 760

What would be the shape of Ethyne?

Why is the shape of ethyne linear when there three bonds instead of 2 like in BeCl2 ?
by Nhi Vo 3A
Fri Oct 28, 2016 12:20 pm
Forum: Lewis Structures
Topic: Lewis Structure of XeF2
Replies: 1
Views: 657

Lewis Structure of XeF2

Why does the lewis structure for XeF2 have Xe with three lone pairs instead of just two to complete an octet?
by Nhi Vo 3A
Tue Oct 25, 2016 11:00 pm
Forum: Trends in The Periodic Table
Topic: Quiz 2 Typo?
Replies: 3
Views: 484

Re: Quiz 2 Typo?

Ohhhh okay that makes sense...I kept thinking it was L . oops :D
by Nhi Vo 3A
Tue Oct 25, 2016 7:44 pm
Forum: Trends in The Periodic Table
Topic: Quiz 2 Typo?
Replies: 3
Views: 484

Quiz 2 Typo?

In the Quiz 2 Preparation number 1: For each pair of compounds below, circle the compound that contains bonds with greater ionic character:

the last option states: AgF or Agl

what is Agl?
by Nhi Vo 3A
Tue Oct 25, 2016 7:33 pm
Forum: Hybridization
Topic: Will hybrid orbitals be on the quiz?
Replies: 2
Views: 262

Will hybrid orbitals be on the quiz?

Will questions like what if the hybridization of the central atom in a molecule or what are the hybrid orbitals be on the the upcoming quiz?
by Nhi Vo 3A
Tue Oct 25, 2016 7:08 pm
Forum: Lewis Structures
Topic: Why is He2 not a stable molecule? [ENDORSED]
Replies: 1
Views: 2932

Why is He2 not a stable molecule? [ENDORSED]

Using molecular orbital theory, state why He2 not a stable molecule?

Thank you!
by Nhi Vo 3A
Fri Oct 21, 2016 11:36 am
Forum: Trends in The Periodic Table
Topic: What is the difference between electron affinity and electronegativity?
Replies: 3
Views: 632

What is the difference between electron affinity and electronegativity?

What is the difference between electron affinity and electronegativity?

They seem similar to me.
by Nhi Vo 3A
Wed Oct 19, 2016 10:16 am
Forum: Quantum Numbers and The H-Atom
Topic: 2.13 Homework Question [ENDORSED]
Replies: 3
Views: 475

Re: 2.13 Homework Question [ENDORSED]

Thank you!
by Nhi Vo 3A
Tue Oct 18, 2016 12:01 pm
Forum: Quantum Numbers and The H-Atom
Topic: 2.13 Homework Question [ENDORSED]
Replies: 3
Views: 475

2.13 Homework Question [ENDORSED]

2.13 Describe the orientation of the lobes of the px, py, and pz orbitals with respect to the cartesian axes.
by Nhi Vo 3A
Wed Oct 12, 2016 8:10 pm
Forum: Empirical & Molecular Formulas
Topic: What is the molecular formula of xylitol?
Replies: 2
Views: 528

What is the molecular formula of xylitol?

Xylitol, a sugar substitute, has a mass composition of C 39.43%, O 52.58%, H 7.88%, and a molar mass of 152.15 g/mol. What is its molecular formula? I found the moles for C, O, and H which are 3.283 mol C, 3.286 mol O, and 7.817 mol H. When I divided everything by 3.283, I got C: 1, H: 2.378, and O ...
by Nhi Vo 3A
Wed Oct 12, 2016 6:48 pm
Forum: Balancing Chemical Reactions
Topic: Balanced Equation for combustion of CH3OH
Replies: 1
Views: 565

Balanced Equation for combustion of CH3OH

Write a balanced equation for the combustion of CH3OH.

Would the product of any combustion reaction have water and CO2?
by Nhi Vo 3A
Mon Oct 10, 2016 8:39 pm
Forum: Photoelectric Effect
Topic: Post Module Questions
Replies: 1
Views: 291

Post Module Questions

1. In photoelectric experiments, typically what part of the electromagnetic spectrum is the incoming light? Is the answer ultraviolet? 2. Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. Calculate the ener...
by Nhi Vo 3A
Mon Oct 10, 2016 1:42 pm
Forum: Photoelectric Effect
Topic: Given the kinetic energy, how do you find the energy? [ENDORSED]
Replies: 4
Views: 855

Re: Given the kinetic energy, how do you find the energy? [ENDORSED]

Thank you! Your explanation was very clear.
by Nhi Vo 3A
Mon Oct 10, 2016 1:18 pm
Forum: Einstein Equation
Topic: What is the difference between deltaE=hv and E=hv?
Replies: 5
Views: 3010

What is the difference between deltaE=hv and E=hv?

#10 in workbook: An excited hydrogen atom emits light with a frequency of 1.14 x 10^14 Hz to reach the energy level for which n=4. In what principle quantum level did the electron begin? The worked out solution uses the equation deltaE= hv to find energy. My confusion is how do I know when the equat...
by Nhi Vo 3A
Thu Oct 06, 2016 3:27 pm
Forum: Photoelectric Effect
Topic: Given the kinetic energy, how do you find the energy? [ENDORSED]
Replies: 4
Views: 855

Given the kinetic energy, how do you find the energy? [ENDORSED]

In a second experiment a shorter wavelength light source is used resulting in ejected electrons with a kinetic energy of 4.200 x 10-19J. What is the energy of this incident light? What is the wavelength of this incident light? What is the difference between the kinetic energy and just the energy of ...
by Nhi Vo 3A
Thu Oct 06, 2016 2:52 pm
Forum: Photoelectric Effect
Topic: Module Questions
Replies: 1
Views: 269

Module Questions

When the energy per photon is equal to the energy required to remove an electron, what is this energy called? Is the answer threshold energy? Also, if long wavelength light is not ejecting electrons from a metal surface will increasing the intensity of the light result in electrons being ejected? Th...
by Nhi Vo 3A
Wed Oct 05, 2016 1:27 pm
Forum: Properties of Light
Topic: 1.69 Homework Problem [ENDORSED]
Replies: 2
Views: 505

1.69 Homework Problem [ENDORSED]

1.69 : In a recent suspense film, two secret agents must penetrate a criminal's stronghold monitored by a lithium photomultiplier cell that is continually bathed in light from a laser. If the beam of light is broken, an alarm sounds. The agents want to use a handheld laser to illuminate the cell whi...
by Nhi Vo 3A
Wed Oct 05, 2016 12:58 pm
Forum: Einstein Equation
Topic: 1.65 : Will visible light be able to break C-C bond? [ENDORSED]
Replies: 1
Views: 2604

1.65 : Will visible light be able to break C-C bond? [ENDORSED]

1.65 : The energy required to break a C-C bond in a molecule is 348 kJ/mol. Will visible light be able to break this bond? If yes, what is the color of the light? If not, what type of electromagnetic radiation will be suitable?

Also, how do I convert from kj/mol to just joules?

Thank you
by Nhi Vo 3A
Sun Oct 02, 2016 4:02 pm
Forum: Properties of Light
Topic: 1.57 : Wavelength of next line in series ?
Replies: 1
Views: 473

1.57 : Wavelength of next line in series ?

1.57 : Lines in the Balmer series of the hydrogen spectrum are observed at 656.3, 486.1, 434.0, and 410.2 nm. What is the wavelength of the next line in the series?
by Nhi Vo 3A
Sun Oct 02, 2016 2:47 pm
Forum: Properties of Light
Topic: Self Test 1.5A: Calculating longest wavelength given work function [ENDORSED]
Replies: 2
Views: 815

Self Test 1.5A: Calculating longest wavelength given work function [ENDORSED]

Question : Self Test 1.5 A in the textbook :

The work function of zinc is 363 eV. What is the longest wavelength of electromagnetic radiation that could electrons from zinc?

How do I solve this?
by Nhi Vo 3A
Fri Sep 30, 2016 10:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Is the Periodic Sheet Allowed on Quizzes and Tests?
Replies: 4
Views: 432

Is the Periodic Sheet Allowed on Quizzes and Tests?

For quizzes, are we allowed to use the periodic table and formula sheet that came along with the course reader?
by Nhi Vo 3A
Tue Sep 27, 2016 10:27 pm
Forum: Balancing Chemical Reactions
Topic: H.13 How To Write This Chemical Equation?
Replies: 4
Views: 1976

Re: H.13 How To Write This Chemical Equation?

Okay that makes sense. Thank you!
by Nhi Vo 3A
Tue Sep 27, 2016 11:55 am
Forum: Empirical & Molecular Formulas
Topic: L.39 Question: Empirical Formula of Oxide
Replies: 3
Views: 635

L.39 Question: Empirical Formula of Oxide

L.39. A 1.50-g sample of metallic tin was placed in a 26.45-g crucible and heated until all the tin had reacted with the oxygen in air to form an oxide. The crucible and product together were found to weigh 28.35 g. a). What is the empirical formula of the oxide? b). Write the name of the oxide. I f...
by Nhi Vo 3A
Mon Sep 26, 2016 5:24 pm
Forum: Balancing Chemical Reactions
Topic: H.13 How To Write This Chemical Equation?
Replies: 4
Views: 1976

Re: How To Write This Chemical Equation?

For some reason, my question was like that. Thank you for your help!
by Nhi Vo 3A
Mon Sep 26, 2016 11:53 am
Forum: Balancing Chemical Reactions
Topic: H.13 How To Write This Chemical Equation?
Replies: 4
Views: 1976

H.13 How To Write This Chemical Equation?

H.13. When nitrogen and oxygen gases react in the hot exhaust environment of an automobile engine, nitric oxide gas, NO, is formed. After it escapes into the atmosphere with the other gas on a solution of sodium sulfide, Na2S, in alcohol, which, in turn, is made by the reaction of hydrogen sulfide g...

Go to advanced search