Search found 66 matches

by Lopez_Melissa-Dis4E
Sat Mar 16, 2019 8:19 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: FORMULAS
Replies: 2
Views: 98

Re: FORMULAS

On Lavelle's Chemistry page there is the list of constants and equations that are provided on the exam.
by Lopez_Melissa-Dis4E
Sat Mar 16, 2019 8:17 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb calorimeter
Replies: 6
Views: 148

Re: Bomb calorimeter

For a bomb calorimeter, the volume is constant.
by Lopez_Melissa-Dis4E
Sat Mar 16, 2019 8:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Slow and Fast step
Replies: 4
Views: 171

Re: Slow and Fast step

I believe that the slow step (rate determining step) will always be given.
by Lopez_Melissa-Dis4E
Fri Mar 08, 2019 6:20 pm
Forum: Second Order Reactions
Topic: Final
Replies: 30
Views: 430

Re: Final

I believe the final is commutative and will cover all we have learned throughout the quarter.
by Lopez_Melissa-Dis4E
Fri Mar 08, 2019 6:10 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Pt
Replies: 14
Views: 208

Re: Pt

Platinum is only used when you have an aqueous solution/gaseous solution as your anode/cathode. Therefore, you will only use Pt(s) in you cell diagram if you have a nonconducting solid.
by Lopez_Melissa-Dis4E
Fri Mar 08, 2019 6:08 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow Step
Replies: 5
Views: 76

Re: Slow Step

You can only go as fast as your slowest reaction, therefore it is determines your overall rate law.
by Lopez_Melissa-Dis4E
Sat Mar 02, 2019 11:46 am
Forum: Balancing Redox Reactions
Topic: Max Potential
Replies: 3
Views: 59

Re: Max Potential

The equation deltaG=-nFE dives way the relationship between deltaG and E.
by Lopez_Melissa-Dis4E
Sat Mar 02, 2019 11:44 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams (Using Platinum)
Replies: 10
Views: 126

Re: Cell Diagrams (Using Platinum)

You use Platinum(s) when there is no conducting metal on either the anode/cathode side of the reaction.
by Lopez_Melissa-Dis4E
Sat Mar 02, 2019 11:42 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.23, part a
Replies: 2
Views: 58

Re: 14.23, part a

Mercury is an electron conductor itself, therefore it does not need a solid like Pt(s) written in the cell diagram.
by Lopez_Melissa-Dis4E
Fri Feb 22, 2019 9:32 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 7
Views: 153

Re: Test 2

The test will cover up to todays lecture in electrochemistry and Gibbs Free Energy.
by Lopez_Melissa-Dis4E
Fri Feb 22, 2019 9:20 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Midterm Question
Replies: 8
Views: 142

Re: Midterm Question

I believe either one gave approximately the same answer.
by Lopez_Melissa-Dis4E
Fri Feb 22, 2019 9:18 pm
Forum: Balancing Redox Reactions
Topic: Test 2 Textbook Sections
Replies: 2
Views: 60

Re: Test 2 Textbook Sections

Test 2 will cover almost all of chapter 14, not including the Nernst equation.
by Lopez_Melissa-Dis4E
Fri Feb 22, 2019 9:12 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Units of Delta G
Replies: 5
Views: 76

Re: Units of Delta G

The units will either be in J or kJ depending on what it is asking. Sometimes it will be J/mol or kJ/mol.
by Lopez_Melissa-Dis4E
Tue Feb 19, 2019 12:22 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Test 3
Replies: 10
Views: 155

Re: Test 3

It should cover Gibbs Free Energy and topics that we learn during week 7.
by Lopez_Melissa-Dis4E
Tue Feb 19, 2019 12:20 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: TEST 3
Replies: 7
Views: 225

Re: TEST 3

Test 2 should begin next week, I think it should cover Gibbs Free Energy and other topics we cover this week.
by Lopez_Melissa-Dis4E
Tue Feb 19, 2019 12:15 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Midterm Grades
Replies: 35
Views: 580

Re: Midterm Grades

I believe it takes them about 1 week to grade them after the midterm, however since Monday was a holiday then maybe it will take longer.
by Lopez_Melissa-Dis4E
Fri Feb 15, 2019 5:01 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: work
Replies: 5
Views: 78

Re: work

When work is (+), then work is being done ON the system.
When work is (-), then work is being done BY the system.
by Lopez_Melissa-Dis4E
Fri Feb 15, 2019 4:55 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Midterm Grades
Replies: 35
Views: 580

Re: Midterm Grades

It takes them about a week to grade all the midterms, so hopefully by Wednesday or Thursday of week seven.
by Lopez_Melissa-Dis4E
Fri Feb 15, 2019 4:51 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Cv vs. Cp
Replies: 6
Views: 200

Re: Cv vs. Cp

Cv means constant volume and Cp means constant pressure.
by Lopez_Melissa-Dis4E
Fri Feb 08, 2019 11:11 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Delta U
Replies: 3
Views: 66

Re: Delta U

Delta U stands for the change in internal energy of a system that is solved by adding work and heat.
by Lopez_Melissa-Dis4E
Fri Feb 08, 2019 11:09 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant Pressure Problem
Replies: 2
Views: 52

Re: Constant Pressure Problem

You would have to divide by moles so that the unit can cancel out and you are only left with Joules.
by Lopez_Melissa-Dis4E
Fri Feb 08, 2019 11:06 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Practice Midterm
Replies: 3
Views: 101

Re: Practice Midterm

He has not, but I'm sure it will be up this weekend since his review session is on Monday.
by Lopez_Melissa-Dis4E
Fri Feb 01, 2019 1:48 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Midterm
Replies: 4
Views: 97

Re: Midterm

The midterm is during week 6, on February 13 @ 6-8pm. He will later announce each location for the midterm.
by Lopez_Melissa-Dis4E
Fri Feb 01, 2019 1:41 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Enthalpy
Replies: 6
Views: 75

Re: Enthalpy

Endothermic requires heat, therefore delta H is positive.
Exothermic releases heat, therefore delta H is negative.
Whether you are forming bonds (endothermic), or breaking bonds (exothermic) you would refer to your positive/negative value of delta H.
by Lopez_Melissa-Dis4E
Fri Feb 01, 2019 1:35 pm
Forum: Phase Changes & Related Calculations
Topic: U and its relations to work
Replies: 8
Views: 126

Re: U and its relations to work

The equation that relates U to work is delta U= q+w, U represents the change in internal energy.
by Lopez_Melissa-Dis4E
Fri Jan 25, 2019 1:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units When Calculating Equilibrium Constant
Replies: 4
Views: 65

Re: Units When Calculating Equilibrium Constant

Because the equilibrium constant is a ratio, the units would cancel each other out. Therefore no units are required.
by Lopez_Melissa-Dis4E
Fri Jan 25, 2019 1:25 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Test 1
Replies: 9
Views: 156

Re: Test 1

You should assume that most equations will be given on the constant/equation sheet.
by Lopez_Melissa-Dis4E
Fri Jan 25, 2019 1:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: increasing pressure, what happens to concentration?
Replies: 10
Views: 181

Re: increasing pressure, what happens to concentration?

According to Le Chatelier's Principle, if you increase the pressure the reaction will go towards the side with less moles.
by Lopez_Melissa-Dis4E
Fri Jan 18, 2019 1:44 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Kw
Replies: 6
Views: 121

Re: Kw

Yes they are equal when in pure water.
by Lopez_Melissa-Dis4E
Fri Jan 18, 2019 1:42 pm
Forum: Ideal Gases
Topic: Homework Week 2
Replies: 10
Views: 148

Re: Homework Week 2

Yes, all homework is due during your specific discussion section. The only exception was week 1.
by Lopez_Melissa-Dis4E
Fri Jan 18, 2019 1:41 pm
Forum: Administrative Questions and Class Announcements
Topic: Studying for First Discussion Test
Replies: 10
Views: 143

Re: Studying for First Discussion Test

I work through all the homework problems and reread the chapters along with the lecture notes! It’s really helpful to attend the step up sessions or form a study group so you can teach each other what you don’t know. Hope this helped!
by Lopez_Melissa-Dis4E
Fri Jan 11, 2019 6:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE
Replies: 2
Views: 43

Re: ICE

ICE stands for Initial Molarity, Change in Molarity, and Equilibrium Molarity.
by Lopez_Melissa-Dis4E
Fri Jan 11, 2019 5:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp vs Kc
Replies: 6
Views: 73

Re: Kp vs Kc

I believe it's a matter of what the question is asking. I would assume that they are equally important.
by Lopez_Melissa-Dis4E
Fri Jan 11, 2019 5:50 pm
Forum: Ideal Gases
Topic: Units
Replies: 19
Views: 223

Re: Units

Kelvin should be used when calculating these type of problems due to the fact that 0 Kelvin is absolute 0.
by Lopez_Melissa-Dis4E
Thu Dec 06, 2018 9:49 pm
Forum: Naming
Topic: 9C1 7th edition
Replies: 2
Views: 69

Re: 9C1 7th edition

It all has to do with the overall charge of the compound, if it has a negative charge you will add -ate to your transition metal.
by Lopez_Melissa-Dis4E
Thu Dec 06, 2018 9:46 pm
Forum: Properties of Light
Topic: Speed of light
Replies: 13
Views: 232

Re: Speed of light

Personally, I would just use the constant given on the formula sheet to be safe. However you should be aware of significant figures to ensure the correct answer.
by Lopez_Melissa-Dis4E
Thu Dec 06, 2018 9:44 pm
Forum: Naming
Topic: Regarding the test... [ENDORSED]
Replies: 12
Views: 3776

Re: Regarding the test... [ENDORSED]

I believe we will be tested on coordination compounds. We are expected to name them, derive the formula from the name, and draw their structures. It would also be beneficial to know how they are significant in a biological point of view. I hope this helps!
by Lopez_Melissa-Dis4E
Thu Dec 06, 2018 9:42 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg and Wavelength
Replies: 11
Views: 414

Re: Heisenberg and Wavelength

Because momentum and wavelength are inverses of one another, if you know the precise value for one then you don't know the value of the other. (vice versa) That is why it is named the Heisenburg Uncertainty Principle.
by Lopez_Melissa-Dis4E
Fri Nov 30, 2018 12:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 11
Views: 169

Re: Lone Pairs

Lone pairs repel the other bonding pairs, therefore the bonding pairs push away from the lone pairs causing a change in the VSPER formula, molecular geometry, hybridization, polarity, and bond angles.
by Lopez_Melissa-Dis4E
Fri Nov 30, 2018 12:29 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxidation number
Replies: 9
Views: 135

Re: Oxidation number

The oxidation number is basically how many electrons have been lost or gained in a coordination compound.
by Lopez_Melissa-Dis4E
Fri Nov 30, 2018 12:25 pm
Forum: Lewis Acids & Bases
Topic: HF
Replies: 5
Views: 119

Re: HF

It is such a weak acid because the bonds associated with it are strong and F is highly electronegative.
by Lopez_Melissa-Dis4E
Sun Nov 25, 2018 5:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Linear structure with lone pairs
Replies: 6
Views: 121

Re: Linear structure with lone pairs

Riley Dean 1D wrote:All of these are 180 degrees right? regardless of the number of lone pairs of elections?

Yes! If it is linear it will be 180 degrees.
by Lopez_Melissa-Dis4E
Sun Nov 25, 2018 5:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Ch.4 #73 (6th Edition)
Replies: 2
Views: 41

Re: Ch.4 #73 (6th Edition)

I believe you need to find the Lewis structure to determine whether it is a radical or not. If the total valence electrons are negative, you most likely have a radical.
by Lopez_Melissa-Dis4E
Sun Nov 25, 2018 4:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: pi and sigma bonds
Replies: 9
Views: 149

Re: pi and sigma bonds

Can someone please explain the concepts behind pi and sigma bonds?
by Lopez_Melissa-Dis4E
Fri Nov 16, 2018 10:59 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Linear Example
Replies: 4
Views: 64

Re: Linear Example

When you add up the total valence electrons of BeCl2 you will see you only have 16 valence electrons and they fulfill Cl octet rule along with getting their formal charge to 0. Be's formal charge is also 0, thus making it a stable molecule with no extra electrons to add as lone pairs.
by Lopez_Melissa-Dis4E
Fri Nov 16, 2018 10:48 am
Forum: SI Units, Unit Conversions
Topic: lewis structure shape
Replies: 6
Views: 289

Re: lewis structure shape

Lavelle has covered only 11 shapes and their corresponding angels so I am assuming those will be the only we will need to know for the upcoming test and final.
by Lopez_Melissa-Dis4E
Wed Nov 14, 2018 4:03 pm
Forum: Administrative Questions and Class Announcements
Topic: Grades
Replies: 5
Views: 161

Re: Grades

He uses the class average score in order to determine final grades. I hope this helped.
by Lopez_Melissa-Dis4E
Fri Nov 09, 2018 12:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape
Replies: 2
Views: 57

Molecular Shape

Will we be going over molecular shapes in lecture today? I just wanted to get a head start on the topic if we will be covering it today.
by Lopez_Melissa-Dis4E
Fri Nov 09, 2018 11:50 am
Forum: Trends in The Periodic Table
Topic: Bond Lenghts
Replies: 6
Views: 262

Re: Bond Lenghts

The Lewis Structure would be critical in the process of finding out the bond lengths.
by Lopez_Melissa-Dis4E
Fri Nov 09, 2018 11:47 am
Forum: Bond Lengths & Energies
Topic: Strength of Bonds
Replies: 9
Views: 222

Re: Strength of Bonds

I believe that it is because the stronger the bond, the harder it is to break resulting in a higher boiling and melting point.
by Lopez_Melissa-Dis4E
Fri Nov 02, 2018 11:29 am
Forum: *Shrodinger Equation
Topic: Midterm
Replies: 6
Views: 289

Re: Midterm

There will be no calculations on the Schrodinger equation because it contains multivariable calculus that is beyond the scope of this course. Overall, we would have to understand its role in wavelength along with psi and psi^2. As mentioned above.
by Lopez_Melissa-Dis4E
Fri Nov 02, 2018 11:26 am
Forum: Properties of Electrons
Topic: De Broglie Formula vs. Speed of Light Formula
Replies: 5
Views: 234

Re: De Broglie Formula vs. Speed of Light Formula

De Broglie is used when the mass of some particle is involved. (mass of an electron, proton, neutron...etc) The speed of light formula refers to a photon.
by Lopez_Melissa-Dis4E
Fri Nov 02, 2018 11:18 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Probability of finding an electron
Replies: 1
Views: 90

Re: Probability of finding an electron

I believe we will not be calculating this any time soon since the Schrodinger Equation is very complex and involves multi-variable calculus. It is beyond the scope of this course.
by Lopez_Melissa-Dis4E
Fri Nov 02, 2018 11:12 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge of Ions
Replies: 9
Views: 193

Re: Formal Charge of Ions

When it comes to formal charge your goal is for it to be zero (or closest to zero) because it represents the stability of the specific atom. That is why you take the formal charge of each atom present in your compound, to see if they are all formally charged to 0.
by Lopez_Melissa-Dis4E
Fri Nov 02, 2018 11:08 am
Forum: Dipole Moments
Topic: Midterm Dipole Moments?
Replies: 4
Views: 84

Re: Midterm Dipole Moments?

I believe Dr. Lavelle said that we needed to know up to Lewis Acids and Bases for the midterm. What we will be learning today corresponds to the next test and the final.
by Lopez_Melissa-Dis4E
Fri Nov 02, 2018 11:06 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge purpose
Replies: 33
Views: 1202

Re: Formal charge purpose

Moris 1H wrote:Why us calculating formal charge important for every Lewis Structure?


Calculating the formal charge is important because when FC=0 that is when your structure is the most stable. That way you can verify that your structure is correct in terms of your placement of electrons.
by Lopez_Melissa-Dis4E
Fri Nov 02, 2018 11:02 am
Forum: Lewis Structures
Topic: Lewis Acid and Bases
Replies: 2
Views: 44

Re: Lewis Acid and Bases

Yes, Dr. Lavelle stated that we would need to know Lewis Acids and Bases for the midterm. Basically, a Lewis Acid accepts pairs of electrons and a Lewis Base will donate. You would have to figure out the Lewis Dot structure in order to choose between a Lewis Acid or Base.
by Lopez_Melissa-Dis4E
Mon Oct 29, 2018 9:16 pm
Forum: Student Social/Study Group
Topic: Studying for tests/midterm
Replies: 18
Views: 1090

Re: Studying for tests/midterm

I think the best way to study would be to help out your peers because it will reinforce your own learning. Also going over the modules and homework problems can be super helpful.
by Lopez_Melissa-Dis4E
Fri Oct 26, 2018 6:30 pm
Forum: Ionic & Covalent Bonds
Topic: Exceptions
Replies: 4
Views: 117

Exceptions

How are H, He, Li, Be exceptions to the octet rule? What does this mean? If we went over it in class, I totally missed it.
by Lopez_Melissa-Dis4E
Fri Oct 26, 2018 6:25 pm
Forum: Ionic & Covalent Bonds
Topic: Chemical Bonding and Periodic Trends
Replies: 4
Views: 93

Chemical Bonding and Periodic Trends

Are periodic trends directly related to bonding? If so, can someone please elaborate on the concept.
by Lopez_Melissa-Dis4E
Fri Oct 26, 2018 6:21 pm
Forum: Lewis Structures
Topic: octets
Replies: 13
Views: 225

Re: octets

An element's goal is to complete a full outer shell meaning they want to have 8 valence electrons. This means all have to complete the orbital in order to be able to move on to the next.
by Lopez_Melissa-Dis4E
Fri Oct 26, 2018 6:18 pm
Forum: Ionic & Covalent Bonds
Topic: Chemical Bonding
Replies: 8
Views: 130

Re: Chemical Bonding

Today we reviewed on the high school level of chemical bonding. We spoke about chemical bonds, ionic and covalent. We also began Lewis Dot Structures. We will be continuing this concept more in-depth throughout week 5.
by Lopez_Melissa-Dis4E
Mon Oct 22, 2018 8:53 pm
Forum: DeBroglie Equation
Topic: 1B 15 7th edition
Replies: 6
Views: 153

Re: 1B 15 7th edition

For part c I also keep getting 12nm, it might be a typo in the book.
by Lopez_Melissa-Dis4E
Fri Oct 19, 2018 5:41 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation
Replies: 1
Views: 33

Re: Rydberg Equation

The Rydberg Equation is R[1/n1^2-1/n2^2]= 1/lambda. We are encouraged to use En= -hR/n^2 and then Delta E= E(final)-E(initial).
by Lopez_Melissa-Dis4E
Fri Oct 19, 2018 4:54 pm
Forum: Photoelectric Effect
Topic: Test 2
Replies: 16
Views: 368

Re: Test 2

We won't be directly tested on the material from outline 1, but we are required to apply it if necessary. I hope this helped!
by Lopez_Melissa-Dis4E
Tue Oct 16, 2018 5:03 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 7th edition HW Problem 1.A15
Replies: 2
Views: 64

7th edition HW Problem 1.A15

Hello, can someone please explain how to solve HW Problem 1A.15 in the 7th edition of the textbook?

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