Search found 70 matches

by Lauren Ho 2E
Tue Mar 12, 2019 4:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Test 2 #6 Ordering Reducing/Oxidizing Power
Replies: 3
Views: 106

Re: Test 2 #6 Ordering Reducing/Oxidizing Power

For part B. I got that the order of increasing oxidation power was Mg2+ < Ti2+ < Sn2+ because a more positive voltage means a stronger oxidizing agent. I don't know how to solve A and C, though :(
by Lauren Ho 2E
Tue Mar 12, 2019 4:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Inert Electrode
Replies: 2
Views: 39

Re: Inert Electrode

Yes, because an inert electrode is needed whenever there is no conducting metal.
by Lauren Ho 2E
Wed Mar 06, 2019 9:36 pm
Forum: Second Order Reactions
Topic: multiple choice kinetics
Replies: 1
Views: 39

Re: multiple choice kinetics

The answer is (D), and you can find it by process of elimination. (A) we know to be incorrect, and (B) is false because surface area is proportional to chemical reaction speed. (C) is incorrect because reactions between gases are not rapid in ALL cases (e.g. very very low temperature). (E) is incorr...
by Lauren Ho 2E
Wed Mar 06, 2019 9:33 pm
Forum: Second Order Reactions
Topic: multiple choice rate
Replies: 1
Views: 32

Re: multiple choice rate

The overall order is 2+1 = 3.
The order with respect to A is 2, and the order with respect to B is 1.

This makes (C) the answer
by Lauren Ho 2E
Mon Mar 04, 2019 11:22 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Study Advice
Replies: 30
Views: 370

Re: Study Advice

My favorite way to study is by using The Organic Chemistry Tutor on Youtube! His videos with practice problems somehow always follow Dr. Lavelle's outlines perfectly, and Youtube is perfect for studying in the sense that explanations are clear if you are using a good channel to study and for the pau...
by Lauren Ho 2E
Mon Mar 04, 2019 10:43 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Order of Reaction
Replies: 5
Views: 101

Re: Order of Reaction

Here is a visual that I hope helps:
by Lauren Ho 2E
Mon Mar 04, 2019 10:39 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: difference between galvanic and voltaic
Replies: 4
Views: 71

Re: difference between galvanic and voltaic

They are the same, but referred to with two different named because they are named after Luigi Galvani and Alessandro Volta.
by Lauren Ho 2E
Mon Mar 04, 2019 10:29 pm
Forum: General Rate Laws
Topic: Units of Rate Constant
Replies: 4
Views: 57

Re: Units of Rate Constant

Completing 15.9 in the sixth edition should be very helpful in understanding this concept!
by Lauren Ho 2E
Thu Feb 28, 2019 5:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.91
Replies: 1
Views: 26

Re: 14.91

The solution manual states that "a negatively charged electrolyte flows from the cathode to the anode."
by Lauren Ho 2E
Thu Feb 28, 2019 5:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cathode vs anode
Replies: 4
Views: 72

Re: cathode vs anode

You can determine the cathode reaction and anode reaction by seeing which combination would cause you to end up with a greater voltage when the two reactions are combined
by Lauren Ho 2E
Thu Feb 28, 2019 4:59 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Pt inert electrode
Replies: 9
Views: 160

Re: Pt inert electrode

Melody P 2B wrote:Would you add Pt(s) to both sides?


You would add Pt(s) to whichever side lacks solid metal.
by Lauren Ho 2E
Thu Feb 21, 2019 2:41 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Cell Potential
Replies: 2
Views: 65

Re: Standard Cell Potential

Standard corresponds with 1 mole/L, 1 atm, and 25 degrees C
by Lauren Ho 2E
Thu Feb 21, 2019 2:30 pm
Forum: Balancing Redox Reactions
Topic: Homework 14.5 part d
Replies: 4
Views: 65

Re: Homework 14.5 part d

The Solution Manual Errors PDF on Professor Lavelle's website doesn't point to any errors in the solution manual for problem 14.5, so I would assume that the given answer is right
by Lauren Ho 2E
Sun Feb 17, 2019 10:18 pm
Forum: Student Social/Study Group
Topic: Serenade
Replies: 2
Views: 76

Re: Serenade

HAHA thanks, I wish the 1 pm class got serenaded :(
by Lauren Ho 2E
Sun Feb 17, 2019 10:14 pm
Forum: Student Social/Study Group
Topic: absent 2/15
Replies: 3
Views: 68

Re: absent 2/15

More specifically, we discussed the three different ways to find free energy:

1. Using standard enthalpy of formation and standard molar entropy
2. Hess-style approach of adding/subtracting delta G (rxn 1) and delta G (rxn 2)
3. Using G(products) - G(reactants)
by Lauren Ho 2E
Sun Feb 17, 2019 10:10 pm
Forum: Student Social/Study Group
Topic: Chemistry News
Replies: 38
Views: 28248

Re: Chemistry News

Interesting stuff for those interested in art history :)

https://phys.org/news/2019-02-art-acne-georgia-okeeffe.html
by Lauren Ho 2E
Sun Feb 10, 2019 12:00 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work Done
Replies: 2
Views: 58

Re: Work Done

If energy leaves a system, the system does work on its surroundings. If energy enters a system, work is done on the system.
by Lauren Ho 2E
Sun Feb 03, 2019 2:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Review
Replies: 14
Views: 263

Re: Midterm Review

Dr. Lavelle also usually does midterm review during class in the days leading up to the midterm!
by Lauren Ho 2E
Sun Feb 03, 2019 2:33 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calibrating the Calorimeter
Replies: 1
Views: 32

Re: Calibrating the Calorimeter

From http://www.dynamicscience.com.au/tester/solutions1/chemistry/energy/calorimeter.htm : "Calibration of the calorimeter is the determination of how many joules of energy are required to raise the temperature of the contents by one degree Celsius. This is known as the calibration factor of th...
by Lauren Ho 2E
Thu Jan 31, 2019 8:40 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 2
Views: 51

Re: Bond Enthalpies

You would look at the total of all of the bonds: the three C=C bonds and three C-C bonds, for instance.
by Lauren Ho 2E
Thu Jan 31, 2019 8:38 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed System
Replies: 6
Views: 122

Re: Closed System

Closed systems cannot exchange matter with their surroundings, but can exchange energy.

If a sealed beaker is heated, for instance, nothing physically can leave or enter the beaker. However, there will be a heat energy transfer.
by Lauren Ho 2E
Thu Jan 31, 2019 8:36 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Open, closed, or isolated systems
Replies: 10
Views: 189

Re: Open, closed, or isolated systems

Here is a visual I hope will help!
by Lauren Ho 2E
Thu Jan 31, 2019 8:34 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work
Replies: 3
Views: 68

Re: Work

If energy leaves a system, the system does work on its surroundings. If energy enters a system, work is done on the system.
by Lauren Ho 2E
Sat Jan 26, 2019 3:55 pm
Forum: Phase Changes & Related Calculations
Topic: Modules
Replies: 17
Views: 205

Re: Modules

Do the modules tell you your score at the end? Or are they just for practice?
by Lauren Ho 2E
Thu Jan 24, 2019 4:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Tricks for identifying Strong/Weak Acids & Bases
Replies: 5
Views: 102

Tricks for identifying Strong/Weak Acids & Bases

Does anyone know of any tips or tricks that will allow you immediately to identify an acid or base as weak or strong?
by Lauren Ho 2E
Tue Jan 22, 2019 2:18 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ignoring x
Replies: 10
Views: 131

Re: ignoring x

Do we need to write anything to indicate or explain why we have ignored x? Or can we just do it without indication if our problem passes the 5% test?
by Lauren Ho 2E
Thu Jan 17, 2019 10:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: conjugates
Replies: 3
Views: 55

Re: conjugates

This is not necessarily true. For instance, a weak acid/base will have a stronger conjugate base/acid.
by Lauren Ho 2E
Thu Jan 17, 2019 10:45 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q<K
Replies: 4
Views: 107

Re: Q<K

Yes! Here is a visual representation of that:
by Lauren Ho 2E
Sat Jan 12, 2019 2:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating K
Replies: 4
Views: 58

Re: Calculating K

You would use equilibrium concentrations
by Lauren Ho 2E
Sat Jan 12, 2019 2:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.45 6th Edition
Replies: 1
Views: 45

Re: 11.45 6th Edition

You can compare the equilibrium constants for the dissociation of CL 2 versus the dissociation of F 2 to determine stability. Because the dissociation of F 2 has a larger equilibrium constant than that of CL 2 and a large equilibrium constant means that the equilibrium concentration of the products ...
by Lauren Ho 2E
Thu Dec 06, 2018 3:32 pm
Forum: General Science Questions
Topic: Chemistry Community [ENDORSED]
Replies: 7
Views: 217

Re: Chemistry Community [ENDORSED]

Claire Guo 1B wrote:TA's wont be checking if we did three posts every week right? Because I think I have the 30 posts we need but some weeks I forgot and then caught up later.


I think that should be fine!
by Lauren Ho 2E
Tue Dec 04, 2018 7:28 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH scale
Replies: 2
Views: 43

Re: pH scale

This part is a little confusing for me. If, basic solutions have less H3O+ than acids, and the pH log measures the amount of H3O+, then why do the larger numbers (8-14) correspond to bases? pH = -log 10 With this knowledge, the pH of a number like 10 -1 (pH = 1) would be lower than the pH of a numb...
by Lauren Ho 2E
Tue Dec 04, 2018 7:21 pm
Forum: Naming
Topic: Textbook Question 9C.1
Replies: 2
Views: 41

Re: Textbook Question 9C.1

a) says [Fe(CN)6]^4- however the answer is tetracholoroferrate (II) why is iron called ferrate and why is the charge (II) and not (IV) Each CN contributes to a -1 charge, meaning (CN) 6 has a total charge of -6. If [Fe(CN)6]^4- has a net charge of -4 and (CN)6 contributes to -6 of that charge, Fe m...
by Lauren Ho 2E
Tue Dec 04, 2018 7:17 pm
Forum: General Science Questions
Topic: Chemistry Community [ENDORSED]
Replies: 7
Views: 217

Re: Chemistry Community [ENDORSED]

Will our TAs give us points for chem community just by looking up our names and seeing how many posts we have?
by Lauren Ho 2E
Tue Dec 04, 2018 5:37 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Naming Acids
Replies: 1
Views: 42

Re: Naming Acids

From https://courses.lumenlearning.com/introchem/chapter/naming-acids-and-bases/ - Acids are named based on their anion — the ion attached to the hydrogen. In simple binary acids, one ion is attached to hydrogen. Names for such acids consist of the prefix “hydro-“, the first syllable of the anion, a...
by Lauren Ho 2E
Fri Nov 30, 2018 4:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Pentagonal bipyramidal
Replies: 4
Views: 106

Re: Pentagonal bipyramidal

IF7 is an example of a molecule with this shape!
by Lauren Ho 2E
Fri Nov 30, 2018 4:13 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Sigma and Pi Bonds
Replies: 2
Views: 146

Re: Sigma and Pi Bonds

Here's a visual that I hope helps!
by Lauren Ho 2E
Fri Nov 30, 2018 4:00 pm
Forum: Dipole Moments
Topic: Molecular Geometry and polarity
Replies: 5
Views: 90

Re: Molecular Geometry and polarity

Adrian C 1D wrote:If a molecule's molecular geometry is linear, is it a good indicator of the molecule being nonpolar?


Not necessarily, e.g. HCN is linear, but polar
by Lauren Ho 2E
Fri Nov 30, 2018 3:56 pm
Forum: Hybridization
Topic: 2s or s?
Replies: 7
Views: 103

Re: 2s or s?

Andrew Sun 1I wrote:if a question asks what is the hybridization around the central atom, does it need a coefficient to specify which energy level?


My TA said that we don't need to specify which energy level
by Lauren Ho 2E
Thu Nov 29, 2018 12:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Wednesday Lecture Notes
Replies: 3
Views: 115

Re: Wednesday Lecture Notes

Thank you so much!!
by Lauren Ho 2E
Thu Nov 22, 2018 3:18 pm
Forum: Hybridization
Topic: Sixth Edition, Example 4.6
Replies: 2
Views: 53

Re: Sixth Edition, Example 4.6

I think I remember my TA saying that the numbers denoting row are unnecessary (though correct) when writing hybridizations. So in your case, writing them either way would probably be alright!
by Lauren Ho 2E
Thu Nov 22, 2018 3:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: I3- ion shape
Replies: 2
Views: 32

Re: I3- ion shape

I3- ions have three lone pairs around the central I atom, meaning the molecule as a whole has an electron geometry of trigonal bipyramidal and a linear molecular geometry.
by Lauren Ho 2E
Mon Nov 19, 2018 8:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Length and Bond Angles
Replies: 2
Views: 38

Re: Bond Length and Bond Angles

As far as our class is concerned, bond lengths affect bond angles to such a small extent that this effect can be ignored.
by Lauren Ho 2E
Sun Nov 18, 2018 9:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework Week 8 [ENDORSED]
Replies: 7
Views: 1519

Re: Homework Week 8 [ENDORSED]

cara_cavarretta_3F wrote:Even though we still have discussion for Mon-Wed is our homework still due the next week as well? Sorry, just to be sure.


For my discussion, we could either turn in 7 homework problems this week or both sets (14 problems) the following week
by Lauren Ho 2E
Sun Nov 18, 2018 9:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles Between the Same shape
Replies: 6
Views: 86

Re: Bond Angles Between the Same shape

I think bond angles are the same for molecules of the same shape (at least the ones we've learned about so far)
by Lauren Ho 2E
Thu Nov 15, 2018 4:09 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW Q 4.13
Replies: 2
Views: 41

Re: HW Q 4.13

Is this helpful in visualizing the molecular geometry?
by Lauren Ho 2E
Thu Nov 15, 2018 3:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW Q 4.11
Replies: 4
Views: 48

Re: HW Q 4.11

SCl4 has a seesaw molecular geometry because you must take into account the effect that the lone pair on S has on shape; if there was no lone pair on SCl4, the shape would be tetrahedral. If there was no lone pair it would just be SCl4. Would it not be square planar? To be square planar, a molecule...
by Lauren Ho 2E
Thu Nov 15, 2018 3:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW Q 4.11
Replies: 4
Views: 48

Re: HW Q 4.11

SCl4 has a seesaw molecular geometry because you must take into account the effect that the lone pair on S has on shape; if there was no lone pair on SCl4, the shape would be tetrahedral.
by Lauren Ho 2E
Fri Nov 09, 2018 6:21 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability Vs. Polarizing Power
Replies: 3
Views: 135

Re: Polarizability Vs. Polarizing Power

From http://wwwchem.uwimona.edu.jm/courses/CHEM1902/IC10K_MG_Fajans.html : "The ability of a cation to distort an anion is known as its polarization power and the tendency of the anion to become polarized by the cation is known as its polarizability."
by Lauren Ho 2E
Fri Nov 09, 2018 6:15 pm
Forum: Balancing Chemical Reactions
Topic: Combustion Equation
Replies: 18
Views: 708

Re: Combustion Equation

Combustion reactions always have oxygen and a hydrocarbon as reactants and will always produce CO2 and H2O.
by Lauren Ho 2E
Fri Nov 09, 2018 6:13 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 8
Views: 166

Re: Electronegativity

If an element is more electronegative than another atom, it will attract electrons more strongly.
by Lauren Ho 2E
Thu Nov 01, 2018 5:56 pm
Forum: Student Social/Study Group
Topic: Studying
Replies: 7
Views: 294

Re: Studying

I usually study by looking up "[topic] practice problems" on youtube and following along. The Organic Chemistry Tutor's videos have been really helpful for me!
by Lauren Ho 2E
Thu Nov 01, 2018 5:27 pm
Forum: Lewis Structures
Topic: Lewis Structures- formal charge
Replies: 4
Views: 121

Re: Lewis Structures- formal charge

Javier_Ochoa_DIS_3J wrote:This is the equation to find the formal charge.

Valance electrons - (lone pair electrons + number of bonds) = Formal charge.


I like using this equation more than the FC = V - (L + S/2) one because there is less room for error!
by Lauren Ho 2E
Thu Nov 01, 2018 5:20 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radius
Replies: 3
Views: 31

Re: Atomic Radius

To convert from meters to picometers, you multiply the length value by 1e+12
by Lauren Ho 2E
Fri Oct 26, 2018 5:55 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Tricks to remembering orbitals
Replies: 2
Views: 93

Re: Tricks to remembering orbitals

config.jpg


This diagram is super helpful for me!
by Lauren Ho 2E
Fri Oct 26, 2018 5:46 pm
Forum: Quantum Numbers and The H-Atom
Topic: Test #2
Replies: 3
Views: 111

Re: Test #2

Orbitals that have the same energy levels are called degenerate (same n and l quantum numbers)
by Lauren Ho 2E
Thu Oct 18, 2018 3:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Class Grading
Replies: 9
Views: 336

Re: Class Grading

I think our grades will be based off of the class average out of 500 points
by Lauren Ho 2E
Thu Oct 18, 2018 3:10 pm
Forum: Trends in The Periodic Table
Topic: Period Table 'blocks'
Replies: 5
Views: 72

Re: Period Table 'blocks'

For example, Potassium can be written as 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 or [Ar] 4s^1; it is part of the S block
by Lauren Ho 2E
Sun Oct 14, 2018 12:48 pm
Forum: Photoelectric Effect
Topic: Threshold Energy and Energy Levels
Replies: 1
Views: 51

Re: Threshold Energy and Energy Levels

Yes, each metal has a unique threshold energy
by Lauren Ho 2E
Wed Oct 10, 2018 4:39 pm
Forum: Limiting Reactant Calculations
Topic: Test 1
Replies: 3
Views: 186

Re: Test 1

I worked without stopping the entire way through and was probably able to finish with 5 minutes left to check my work.
by Lauren Ho 2E
Wed Oct 10, 2018 4:37 pm
Forum: Properties of Light
Topic: Homework Question 1A15
Replies: 3
Views: 60

Re: Homework Question 1A15

The first step is knowing that this transition is in the Lyman series, but I'm also not sure where to go after this.
by Lauren Ho 2E
Wed Oct 10, 2018 4:28 pm
Forum: SI Units, Unit Conversions
Topic: Quiz 1- Addition to what we should know?
Replies: 5
Views: 228

Re: Quiz 1- Addition to what we should know?

Hannah Padilla 1H wrote:For the first test, will we need to be able to identify molecular formulas from their written name? For example in problem F3.) “Write the formula for nitric acid”


Molecular formulas will be given!
by Lauren Ho 2E
Tue Oct 09, 2018 7:24 pm
Forum: Significant Figures
Topic: 200. decimal sig figs
Replies: 5
Views: 299

Re: 200. decimal sig figs

200.0 offers more precision than 200., so it follows that 200.0 has one more significant figure than 200.
by Lauren Ho 2E
Tue Oct 09, 2018 7:06 pm
Forum: Photoelectric Effect
Topic: post assessment
Replies: 2
Views: 79

Re: post assessment

I agree that the answer should be C; light with a frequency higher than the threshold energy should be able to remove electrons
by Lauren Ho 2E
Tue Oct 09, 2018 7:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 96
Views: 60627

Re: Advice from a Medical Student [ENDORSED]

Thank you for this advice; I switched into this class and was having doubts about which chemistry series would be best for me to take part in, and this makes me feel much more confident!

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