Search found 105 matches

by Ariel Fern 2B
Sat Mar 14, 2020 12:46 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Equilibrium and Kinetics
Replies: 2
Views: 32

Equilibrium and Kinetics

How exactly are equilibrium and kinetics connected, and why do we do this? How does a higher equilibrium constant relate to a rate constant?
by Ariel Fern 2B
Sat Mar 14, 2020 12:15 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 5
Views: 33

Re: Catalysts

Yes, essentially, a catalyst will be consumed as a reactant but reproduced again as a product in the final step. Thus, it cancels out and does not show up in the overall reaction. Just look at the products and reactants between steps; if a substance is consumed but reappears, then it is a catalyst! ...
by Ariel Fern 2B
Sat Mar 14, 2020 11:44 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Elementary Reaction Definition
Replies: 3
Views: 30

Elementary Reaction Definition

What exactly is an elementary reaction, and what makes it different from other chemical reactions? Thank you so much!
by Ariel Fern 2B
Sat Mar 14, 2020 11:38 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Stoichiometric Coefficients and Order of Reactions
Replies: 2
Views: 60

Stoichiometric Coefficients and Order of Reactions

When is the stoichiometric coefficient of a reactant also the order of that reactant? Is that only for elementary reactions? Why is this so? Thanks for any help!
by Ariel Fern 2B
Sat Mar 14, 2020 11:15 am
Forum: General Rate Laws
Topic: Types of Rate Laws
Replies: 2
Views: 49

Types of Rate Laws

Can someone give a brief rundown of the difference between unique, differential, and integral rate laws, and under what conditions each are helpful? I think I'm still trying to process all of the information and put it into categories in my head.
by Ariel Fern 2B
Sun Mar 08, 2020 11:40 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Microscopic Reversibility
Replies: 3
Views: 45

Microscopic Reversibility

What exactly is microscopic reversibility, and how is it related to intermediates and kinetics in general? Thanks for any help!
by Ariel Fern 2B
Sun Mar 08, 2020 11:10 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Test 2
Replies: 7
Views: 87

Re: Test 2

Since it is a Galvanic cell, the E°Cell had to be positive; thus, based on the equation E°Cell = E°Cathode (Reduction) - E°Anode (Oxidation), the Reduction Half Rxn. was the half Rxn. with the more positive E°, and the Oxidation Half Rxn. was the one with the least (most negative) E°. Hope this helps!
by Ariel Fern 2B
Sun Mar 08, 2020 10:31 pm
Forum: General Rate Laws
Topic: 7A.7 Units of Rate Constants
Replies: 2
Views: 32

7A.7 Units of Rate Constants

How do you conceptually determine the units of the rate constants of different orders of reactions, as asked in 7A.7? Is there any equation that you guys use to base this off of? Thanks for any help!
by Ariel Fern 2B
Mon Mar 02, 2020 11:09 am
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: 6O.3
Replies: 1
Views: 83

Re: 6O.3

I am honestly just as confused as you are; I had all the answers reversed as well because I thought the question was based on electrolysis rather than galvanic cells. I guess others have said that the higher reduction potentials still are more favorable in the solution, but like you said, I thought ...
by Ariel Fern 2B
Mon Mar 02, 2020 6:51 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6N.7 B
Replies: 1
Views: 41

6N.7 B

For 6N.7 B, why is the amount of moles (n) only 1 when the half reactions involving H2 into 2H+ have 2 moles of electrons? Any help is appreciated!
by Ariel Fern 2B
Sun Mar 01, 2020 8:58 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6N.1 part B
Replies: 2
Views: 47

Re: 6N.1 part B

The answer in the book is a typo! In the solutions manual, they put that n = 2 moles even though it should only be 1 mole of electrons. By using 1 mole, you get the correct answer of K = 1 x 102 rather than K = 1 x 104! Hope this helps!
by Ariel Fern 2B
Sun Mar 01, 2020 8:07 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Rules for Writing Cell Diagrams
Replies: 2
Views: 42

Rules for Writing Cell Diagrams

Is it fine to include the stoichiometric coefficients when writing the cell diagram? Also, when do we need to include H+ in the cell diagram? Any help is appreciated!
by Ariel Fern 2B
Sun Mar 01, 2020 8:03 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Hg(l) Electrode
Replies: 1
Views: 27

Hg(l) Electrode

Why doesn't Hg(l) need a solid inert electrode even though its half reaction to Hg22+ doesn't include a solid? This is seen in 6M.3 and 6M.5. Thanks for any help!
by Ariel Fern 2B
Sun Mar 01, 2020 7:49 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6L.3 D
Replies: 1
Views: 17

6L.3 D

In 6L.3 D, how did you guys approach writing the half reactions? How did you go from H+ or OH- to the half reactions with H2O and O2? Thanks so much!
by Ariel Fern 2B
Sun Mar 01, 2020 7:40 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Graphite VS. Platinum
Replies: 2
Views: 48

Graphite VS. Platinum

When using an inert electrode, is there any difference between using graphite or platinum? Is there a case where one is better than the other? Thanks so much!
by Ariel Fern 2B
Sun Feb 23, 2020 9:00 am
Forum: Student Social/Study Group
Topic: Midterm 3D
Replies: 3
Views: 74

Re: Midterm 3D

Since the pKa of acetic acid (4.75) is lower than the pH of the specified condition (6), the acetic acid will be able to dissociate into CH3COO-, which has a negative one charge. Hope this helps!!
by Ariel Fern 2B
Sun Feb 23, 2020 8:42 am
Forum: Balancing Redox Reactions
Topic: Oxidation States
Replies: 7
Views: 58

Oxidation States

What is the best method to calculating oxidation numbers? What should I look for first? Any tips to calculate it faster? Thanks for any help!
by Ariel Fern 2B
Sun Feb 23, 2020 8:36 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: platinum
Replies: 4
Views: 29

Re: platinum

Solid platinum is used as a conductor when certain half reactions do not have a conducting solid within their species. For example, the reduction of Fe 3+ to Fe 2+ can occur with both species still being aqueous and dissolved in solution. In order for this to happen though, electrons must flow to th...
by Ariel Fern 2B
Sun Feb 23, 2020 8:31 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: porous disc
Replies: 5
Views: 51

Re: porous disc

Yes, a porous disk does the same function as the salt bridge: keep the current flowing by preventing charge imbalance. Furthermore, a porous disk does not have the anode and cathode in separate solutions; the ions are in the same solution and the ions are intermixed to prevent the charge imbalance. ...
by Ariel Fern 2B
Sun Feb 23, 2020 8:26 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 5
Views: 49

Re: salt bridge

The salt bridge prevents charge buildup/imbalance on the sides of the galvanic cell. If electrons keep flowing to the positive source, the positive charge would soon decrease and become neutral, which would stop the electron flow. Thus, the salt bridge contains spectator ions that keep this from hap...
by Ariel Fern 2B
Sun Feb 16, 2020 11:07 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: ΔS for Irreversible Expansion
Replies: 3
Views: 57

ΔS for Irreversible Expansion

What equation do you use to calculate ΔS for an irreversible expansion? I know that pressure is constant and that work = -PΔV for irreversible expansion, so how does that translate into calculating ΔS? Thanks so much!
by Ariel Fern 2B
Sun Feb 16, 2020 10:58 pm
Forum: Balancing Redox Reactions
Topic: redox reactions
Replies: 3
Views: 38

Re: redox reactions

Yes, as stated above, the easiest way to check for oxidation/reduction is to look at the charges of the ions and see if there is a change in charge! If it has become more negative, then it is being reduced as it has gained electrons, but if it has become more positive, then it has been oxidized beca...
by Ariel Fern 2B
Sun Feb 16, 2020 10:45 pm
Forum: General Science Questions
Topic: Midterm Graded
Replies: 2
Views: 53

Re: Midterm Graded

According to Dr. Lavelle's email, grading of midterms will be finished Tuesday and then, handed back after class on Wednesday! Hope this helps, and best of luck!!
by Ariel Fern 2B
Sun Feb 16, 2020 10:11 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: ΔS of Phase Changes
Replies: 5
Views: 139

ΔS of Phase Changes

When a question asks to calculate the entropy of a phase change at a certain temperature, why do we bring the temperature back down to the specified temperature? Does it stay in that phase when you bring the temperature back down? For example, for calculating the ΔS of vaporization of water at 85°C,...
by Ariel Fern 2B
Sun Feb 16, 2020 10:05 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy of H2 and Most Stable Forms
Replies: 1
Views: 31

Gibbs Free Energy of H2 and Most Stable Forms

Hi! I knew previously that the standard enthalpy of formation of an element in its most stable form is zero, but does this carry to Gibbs Free Energy? I heard that H 2 had a Gibbs Free Energy of 0 kJ/mol, but doesn't it have an entropy that you would use in the ΔG = ΔH - TΔS equation? Thanks for the...
by Ariel Fern 2B
Sun Feb 09, 2020 9:37 pm
Forum: Calculating Work of Expansion
Topic: Ideal Gas Internal Energy
Replies: 4
Views: 38

Ideal Gas Internal Energy

An equation was brought up for an ideal gas that states:

U = 3/2 nRT

Where did this equation come from, and what should it be used for? Thanks so much!
by Ariel Fern 2B
Sun Feb 09, 2020 9:32 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 4f.1
Replies: 2
Views: 24

Re: 4f.1

I would play it safe and always stick to entropy's usual units of Joules/Kelvin. Most of the time when you use the gas constant for entropy problems, you'll be using 8.314 J/K*mol, so it would be better to keep using Kelvin for entropy! I think it's only with Calorimetry and specific heat capacities...
by Ariel Fern 2B
Sun Feb 09, 2020 9:25 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Second and Third Law of Thermodynamics
Replies: 2
Views: 38

Second and Third Law of Thermodynamics

Can someone clarify what the Second and Third Law of Thermodynamics are, and how they are different? They both have to do with entropy, so I think I just need to see the different applications of both! Thanks!
by Ariel Fern 2B
Sun Feb 09, 2020 9:19 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity of Ideal Gases
Replies: 1
Views: 28

Heat Capacity of Ideal Gases

Can someone explain the reasoning as to why the heat capacity of an ideal gas at constant pressure (Cp) is 5/2 R, and why at constant volume (Cv) it is 3/2 R? I got these values from the equation sheet, but I'm unsure of the derivation of the values!
by Ariel Fern 2B
Sat Feb 08, 2020 10:51 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb Calorimeter Differences
Replies: 2
Views: 30

Bomb Calorimeter Differences

I know that a bomb calorimeter reaction occurs at a constant volume, but what difference does it make in calculation problems? E.g. What exactly is the difference between Constant Pressure Calorimetry and Constant Volume Calorimetry in terms of the equations or methods to use? Thanks so much!
by Ariel Fern 2B
Sat Feb 01, 2020 9:31 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity 4C.3
Replies: 3
Views: 45

Heat Capacity 4C.3

How do we find the heat capacity of the Kr gas in 4C.3? I know it has to do with ideal gases and constant volume/pressure, but can someone help me understand this concept? Any help is appreciated!
by Ariel Fern 2B
Sat Feb 01, 2020 9:26 pm
Forum: Calculating Work of Expansion
Topic: integral
Replies: 3
Views: 42

Re: integral

Yes, as the others have stated, you use the integral to account for the infinitesimally small changes in volume. In an irreversible expansion, the integral simplifies into just ΔV because the external pressure is constant and can be pulled out of the integral. However, in a reversible expansion, pre...
by Ariel Fern 2B
Sat Feb 01, 2020 9:05 pm
Forum: Calculating Work of Expansion
Topic: Pressure in Reversible/Irreversible Expansion
Replies: 3
Views: 43

Pressure in Reversible/Irreversible Expansion

Just to clarify: An irreversible expansion refers to constant external pressure, and we can use -PΔV to calculate the work done. However, a reversible expansion involves changes in pressure, and the integral must be taken, which leads to the following equation: w = -nRT*ln(V2/V1). Are these the righ...
by Ariel Fern 2B
Sat Feb 01, 2020 8:48 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: 4A. 5 Isothermic VS. Reversible
Replies: 2
Views: 27

4A. 5 Isothermic VS. Reversible

What is the difference between isothermic and reversible expansion, and which does more work? In 4A.5, it asks whether allowing the gas to expand reversibly or isothermally to the same volume causes more work to be done. Any help is appreciated!
by Ariel Fern 2B
Sat Feb 01, 2020 8:42 pm
Forum: Calculating Work of Expansion
Topic: 4A.3 (HW)
Replies: 2
Views: 52

Re: 4A.3 (HW)

Hey Chloe! Yes, you'll want to use W = -PΔV to find the work, but finding ΔV is definitely the hardest part! To do this, you have to find the area of the pump and multiply it by the distance the pump is depressed. This will be πr 2 times d (distance), which will be (π)(1.5cm) 2 (20.cm). And then, yo...
by Ariel Fern 2B
Sun Jan 26, 2020 7:33 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Delta U
Replies: 2
Views: 21

Delta U

Delta U is the change in internal energy, but what exactly does that mean, and how is it different from enthalpy? Any help is appreciated!
by Ariel Fern 2B
Sun Jan 26, 2020 7:15 pm
Forum: Phase Changes & Related Calculations
Topic: Focus 4 Homework Questions
Replies: 3
Views: 43

Focus 4 Homework Questions

What order are you guys doing the Focus 4 problems? Should I start on Focus 4C or 4D for Thermochemistry? There are definitely stuff that I don't recognize yet, like delta u, so I'd love advice to see how you guys are approaching these problems!
by Ariel Fern 2B
Sun Jan 26, 2020 7:08 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Predicting Molar Heat Capacity
Replies: 3
Views: 52

Predicting Molar Heat Capacity

How would you predict whether one gaseous compound has a higher molar heat capacity? For example, question 4C.1 asks to compare the molar heat capacity of NO to NO2. Any help would be appreciated! Thanks!
by Ariel Fern 2B
Sun Jan 26, 2020 3:57 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State Function
Replies: 1
Views: 16

Re: State Function

As far as I know, a state property/function only depends on the current and initial states to calculate the value; it does not depend on the path it takes to get to the current state. An example outside of chemistry would be driving on a road trip. A state property/function would be just the shortes...
by Ariel Fern 2B
Sun Jan 26, 2020 3:47 am
Forum: Phase Changes & Related Calculations
Topic: Celsius and Kelvin
Replies: 11
Views: 86

Re: Celsius and Kelvin

Yes, like the others have said, you have to add 273.15 to the Celsius temperature to get Kelvin. This is really important for gas laws because the gas constant has units of Kelvin, so never forget to convert the temperature if it's in Celsius!
by Ariel Fern 2B
Sun Jan 19, 2020 10:58 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B. 3 Volume
Replies: 2
Views: 82

Re: 6B. 3 Volume

To find the desired pH you just use the desired concentration 0.025 and you get pH of 1.6. To get the actual solution pH you multiply the molarity by the 0.200 L volume in order to find the desired moles and divide that by 0.250 L to get the new molarity/H3O+ concentration. From there you put that ...
by Ariel Fern 2B
Sun Jan 19, 2020 10:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: acids and bases
Replies: 4
Views: 47

Re: acids and bases

Hey Jina! If you're asking about acid/base reactions in the real world sense, then it would make sense that most reactions have reached equilibrium and are in a state where the products and reactants are being formed at a constant rate. But in terms of this class, we're probably going to come across...
by Ariel Fern 2B
Sun Jan 19, 2020 9:44 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6A.21
Replies: 2
Views: 87

Re: 6A.21

Also, if you look at the stoichiometric coefficients of the autoprotolysis reaction, both the H3O+ and OH- have a coefficient of one; thus, in this reaction, both H3O+ and OH- would have a change + "x" to get to the equilibrium concentration, making them equal.
by Ariel Fern 2B
Sun Jan 19, 2020 9:32 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B. 3 Volume
Replies: 2
Views: 82

6B. 3 Volume

What volumes did you use to get the pH's in this problem? Wouldn't it be 0.200 L and 0.250 L due to the volumetric flasks? I'm not getting the correct pH's using those numbers though, so any help would be appreciated!
by Ariel Fern 2B
Sun Jan 19, 2020 9:21 pm
Forum: Identifying Acidic & Basic Salts
Topic: Strong Acids & Bases Ions
Replies: 3
Views: 98

Strong Acids & Bases Ions

Can someone give me a refresher of how to identify strong acids & bases and the conjugate ions to look out for in salts based on these? Thanks!
by Ariel Fern 2B
Sun Jan 19, 2020 9:10 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Acids and Bases, understanding the Ka value
Replies: 3
Views: 94

Re: Acids and Bases, understanding the Ka value

Yes, as stated above, a large K a value signifies a strong acid. This is because the equilibrium lies toward the products, which includes the hydronium ion and the conjugate base. Ultimately, this means that the acid is more stable in the dissociated form of the hydronium ion and conjugate base rath...
by Ariel Fern 2B
Sat Jan 11, 2020 12:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Assuming +/- x is Negligible
Replies: 4
Views: 46

Assuming +/- x is Negligible

The book says that we can use the approximation technique of making +/- x negligible if the change in composition is less than about 5% of the initial composition. What exactly does this mean in terms of K values? I think I used to remember that if K < 10 -5 that we can use the approximation techniq...
by Ariel Fern 2B
Sat Jan 11, 2020 12:45 pm
Forum: Ideal Gases
Topic: Law of Effusion, Kinetic Model, and Maxwell Distribution
Replies: 3
Views: 42

Law of Effusion, Kinetic Model, and Maxwell Distribution

Focus 3D covers Graham's Law of Effusion, the Kinetic Model of Gases, and the Maxwell Distribution of Speeds. Do you think we will need to know these concepts in depth, and can anyone give a short summary of these, if possible? Thanks!
by Ariel Fern 2B
Sat Jan 11, 2020 12:39 pm
Forum: Ideal Gases
Topic: Conditions for Ideal Gases
Replies: 5
Views: 68

Conditions for Ideal Gases

Under what conditions are most gases considered to be "ideal?" For the most part, can we assume that we can use the ideal gas equation?
by Ariel Fern 2B
Sat Jan 11, 2020 12:28 pm
Forum: Ideal Gases
Topic: Gas Laws
Replies: 6
Views: 79

Gas Laws

I didn't cover gas laws that much in depth in high school, so is it fine if I just know the ideal gas law, PV = nRT? Boyle's Law, Charles's Law, Gay-Lussac's Law, and Avogadro's Principle are all put together into the ideal gas law, so do you think we still need to know each individual one, and does...
by Ariel Fern 2B
Sat Jan 11, 2020 12:09 pm
Forum: Ideal Gases
Topic: Units of Pressure
Replies: 8
Views: 73

Units of Pressure

Do you think that we have to know all the different units of pressure and be able to convert between them? I know that R, the gas constant changes depending on each unit (atm, bar, Torr, kPa, etc.), so would it be useful to be familiar with all of these units? Thanks!
by Ariel Fern 2B
Sat Dec 07, 2019 5:31 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Shape of Coordination Compounds
Replies: 2
Views: 44

Shape of Coordination Compounds

We use VSEPR of the central transition metal ion in order to determine the shape of the coordination compound, right? Does it make any difference if one of the ligands is polydentate or chelating?
by Ariel Fern 2B
Sat Dec 07, 2019 5:16 pm
Forum: Lewis Acids & Bases
Topic: Lewis Acids
Replies: 3
Views: 115

Lewis Acids

Lewis Acids are electron acceptors, but what is the best way to determine that from a Lewis Structure? I'm having a little trouble visualizing the concept of Lewis Acids in terms of where an electron pair can be added on an atom. For Lewis Bases, I can see where lone pairs could be donated, but I'm ...
by Ariel Fern 2B
Sat Dec 07, 2019 5:10 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B. 9
Replies: 1
Views: 42

6B. 9

For this problem, it gives you a [H3O+] of 1.50 mol/L. When I take the negative log of this, I got a negative pH of -0.176 instead of 0.176. Am I overlooking something with the positive/negative sign? Thanks for the help!
by Ariel Fern 2B
Sat Dec 07, 2019 4:56 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Relative Acidity
Replies: 2
Views: 47

Re: Relative Acidity

If an anion is more stable, then it will want to get rid of any H+ in order to get to the more stable, lower energy state! Thus, stable anions tend to form strong acids, which is why resonance structures and electron delocalization are factors to consider when determining relative acidity. Hope this...
by Ariel Fern 2B
Sat Dec 07, 2019 4:51 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: HClO4 VS. H3PO4
Replies: 1
Views: 35

HClO4 VS. H3PO4

How would you explain that HCLO4 is stronger than H3PO4? Do the extra hydrogens in H3PO4 play a role in this being the case, or should I just mention Cl's higher electronegativity leads to more electron withdrawal? Thanks!
by Ariel Fern 2B
Sun Dec 01, 2019 4:57 pm
Forum: Lewis Acids & Bases
Topic: bronsted vs lewis
Replies: 9
Views: 124

Re: bronsted vs lewis

Yes, I agree with the others: Bronsted deals with protons (H+), while Lewis deals with electrons. A tip is that Lewis Acids are e(L)ectron (A)cceptors, so just remember the LA, and you can figure out the rest of them! Hope this helps!
by Ariel Fern 2B
Sun Dec 01, 2019 4:52 pm
Forum: Naming
Topic: Order of ligands in formulas for coordination compounds
Replies: 4
Views: 33

Re: Order of ligands in formulas for coordination compounds

Jorge Ramirez_4H wrote:How about if there is a cation?


I believe cations are written before the coordination compound if there is one. For example, potassium hexacyanidochromate (III) in 9C. 3a. Anions should be written after the cation.
by Ariel Fern 2B
Sun Dec 01, 2019 4:44 pm
Forum: Hybridization
Topic: Writing the hydrization
Replies: 10
Views: 212

Re: Writing the hydrization

Can you explain how to find the hybridization? I've always struggled with it The way I find hybridization is just counting the amount of electron densities around the atom in question. For example, if there are two electron densities, then you need an s-orbital and a p-orbital, so sp. Four electron...
by Ariel Fern 2B
Sun Dec 01, 2019 4:31 pm
Forum: Student Social/Study Group
Topic: Final Topics
Replies: 4
Views: 73

Re: Final Topics

I agree with the others; we haven't really focused on spectroscopy, and there weren't any specific homework problems regarding spectroscopy. I would say that anything on the homework could potentially be on the final, but I don't recall any assigned problems for spectroscopy.
by Ariel Fern 2B
Sun Dec 01, 2019 4:28 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: How do you determine if a ligand can be polydentate?
Replies: 2
Views: 33

Re: How do you determine if a ligand can be polydentate?

A ligand can be polydentate if it has two or more lone pairs that can form a coordinate covalent bond with the transition metal cation. The chloride ion can only be monodentate because it is only one atom and can only donate one electron pair to form a coordinate covalent bond with the cation. Typic...
by Ariel Fern 2B
Sun Nov 24, 2019 6:28 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelate Complex
Replies: 1
Views: 27

Chelate Complex

How would one know if a coordination compound has a chelate shape? What is a usual coordinate number for a chelate complex? Thanks!
by Ariel Fern 2B
Sun Nov 24, 2019 6:25 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Sphere Clarification
Replies: 1
Views: 29

Coordination Sphere Clarification

I'm having trouble visualizing what a coordination sphere is. Is it just the shape that the ligands take around the central metal atom? And the coordination sphere isn't a connection between the ligands, right? It's just something to visualize to help see the shape of the compound, right? Thanks!
by Ariel Fern 2B
Sun Nov 24, 2019 6:11 pm
Forum: Naming
Topic: Polydentate
Replies: 1
Views: 42

Polydentate

What does exactly polydentate mean? It has something to do with the amount of lone pairs a ligand shares, right? Can you also give examples of a monodentate, bidentate, and a tridentate? Thanks!
by Ariel Fern 2B
Sun Nov 24, 2019 6:05 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordinate Covalent Bonds
Replies: 1
Views: 23

Coordinate Covalent Bonds

What exactly is a coordinate covalent bond, and can someone give an example or two? Thanks!
by Ariel Fern 2B
Sun Nov 24, 2019 6:00 pm
Forum: Hybridization
Topic: Valence Bond (VB) Theory
Replies: 1
Views: 42

Valence Bond (VB) Theory

What is the Valence Bond (VB) Theory, and what is its relationship to hybridization?
by Ariel Fern 2B
Sat Nov 16, 2019 9:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent and Angular?
Replies: 6
Views: 70

Re: Bent and Angular?

Yes they are! The book tends to refer to it as "angular" but Prof. Lavelle referred to it as "bent" in lecture, so they should be interchangeable.
by Ariel Fern 2B
Sat Nov 16, 2019 9:32 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Hydrogen Bonding
Replies: 5
Views: 51

Re: Hydrogen Bonding

Yep! Like others have said, it is a special and specific kind of dipole-dipole intermolecular force; it's good to know that hydrogen bonding is the strongest form of dipole-dipole interaction!
by Ariel Fern 2B
Sat Nov 16, 2019 9:26 pm
Forum: General Science Questions
Topic: Test 2
Replies: 5
Views: 67

Re: Test 2

He also said there was one slide from Monday that we would cover, which is distinguishing sigma and pi bonds!
by Ariel Fern 2B
Sat Nov 16, 2019 9:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles with Different Atoms
Replies: 4
Views: 80

Bond Angles with Different Atoms

I know it was mentioned in lecture briefly, but how and why do the bond angles change when an atom is replaced with a more electronegative one? For example, the bond angles in CCl4 VS. CCl3F1. Thanks!
by Ariel Fern 2B
Sat Nov 16, 2019 8:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Subscript on E
Replies: 5
Views: 63

Subscript on E

In the VSEPR formula, is it fine to put a subscript 1 on the E if there is one lone pair on the central atom? The answers in the book just have E, but I like putting E1 to let me know there is only one pair. For example, AX3E1. Thanks!
by Ariel Fern 2B
Sat Nov 09, 2019 9:51 pm
Forum: Dipole Moments
Topic: 3F.5
Replies: 2
Views: 30

Re: 3F.5

Fluorine is more electronegative, but that only means that it will have a stronger hold on the electrons in its own bond between its central carbon atom than the other molecule will have. This question is asking about intermolecular forces: the attraction between molecules, not the atoms. The argum...
by Ariel Fern 2B
Sat Nov 09, 2019 9:39 pm
Forum: Dipole Moments
Topic: Dipole Dipole
Replies: 3
Views: 29

Re: Dipole Dipole

Another trick that helps is checking whether the Lewis Structure is asymmetric or has a bent angle (like in an H 2 O molecule). Typically, looking at the Lewis Structure and seeing elements not in symmetry, especially with lone pairs, helps determine whether or not a molecule will be polar. Hope thi...
by Ariel Fern 2B
Sat Nov 09, 2019 9:26 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: London Dispersion Forces VS. Induced Dipole - Induced Dipole
Replies: 2
Views: 27

London Dispersion Forces VS. Induced Dipole - Induced Dipole

Is there a difference between London Dispersion Forces (LDF's) and Induced Dipole - Induced Dipole, or are these terms interchangeable? I was much more familiar with using the term LDF's, so I was just want to ensure that I'm using it correctly. LDF's were explained to me as temporary charges on a m...
by Ariel Fern 2B
Sat Nov 09, 2019 9:17 pm
Forum: Ionic & Covalent Bonds
Topic: Comparing Strengths of Ionic & Covalent Bonds
Replies: 2
Views: 54

Comparing Strengths of Ionic & Covalent Bonds

Even though the signs are opposite, is it allowed to compare the strengths of ionic and covalent bonds based on their potential energy and dissociation energy, respectively? For example, if the covalent bond strength between HF is 543 kJ/mol, and the interaction potential energy between Na + and Cl ...
by Ariel Fern 2B
Sat Nov 09, 2019 9:00 pm
Forum: Bond Lengths & Energies
Topic: Positive Dissociation Energy & Negative Interaction Potential Energy
Replies: 1
Views: 36

Positive Dissociation Energy & Negative Interaction Potential Energy

Can someone clarify why dissociation energies are always positive in covalent bonds, but interaction potential energy is always negative? What do these signs signify? Thanks!
by Ariel Fern 2B
Sun Nov 03, 2019 9:48 pm
Forum: Trends in The Periodic Table
Topic: Run Down of Trends
Replies: 4
Views: 105

Re: Run Down of Trends

When I think about the trends, I like to think about them conceptually! Going across a row (L to R), the electrons occupy the same shell, so there is less shielding from the nucleus. As a result, they have a greater pull to the nucleus and are much smaller in radius. When you go down a group, the e...
by Ariel Fern 2B
Sun Nov 03, 2019 9:45 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability and Covalent Character
Replies: 5
Views: 73

Polarizability and Covalent Character

Can anybody clarify the connection between polarizability of ions and their covalent character when bonded with another ion? Larger ions have higher polarizing power, right? I am just trying to visualize what it means by covalent character though; any thoughts would be helpful!
by Ariel Fern 2B
Sun Nov 03, 2019 9:39 pm
Forum: Lewis Structures
Topic: Determining Atom Arrangement
Replies: 1
Views: 32

Determining Atom Arrangement

For larger molecules, what is the best way to go about arranging the atoms? For example in 2B.11, the organic molecules are quite large in terms of number of atoms. I've used trial and error, but is there a better way to determine which order the atoms go in and whether to bond a hydrogen with an ox...
by Ariel Fern 2B
Sun Nov 03, 2019 9:34 pm
Forum: Octet Exceptions
Topic: d-Orbitals
Replies: 2
Views: 42

d-Orbitals

I know that atoms in period 3 or higher can potentially accommodate more than 8 electrons due to the d-orbitals, but is there a sure way to know when the octet rule needs to be exceeded? For instance, in BrF 3 , Br exceeds 8 electrons, but in BrO - , Br follows the octet rule. Is there any way I can...
by Ariel Fern 2B
Sun Nov 03, 2019 9:22 pm
Forum: Trends in The Periodic Table
Topic: Run Down of Trends
Replies: 4
Views: 105

Run Down of Trends

Can someone give me a quick and easy way to think about trends? Like tips to remember the arrows of decreasing to increasing without having to look up values? Also, when elements are in a different period and group, how should I think about trends (for example, trying to determine whether chlorine, ...
by Ariel Fern 2B
Sun Nov 03, 2019 3:59 pm
Forum: Lewis Structures
Topic: Steps to Drawing a Lewis Structure
Replies: 6
Views: 60

Steps to Drawing a Lewis Structure

Does anybody have like a "step by step" list in how they draw Lewis Structures? So far I feel like I'm all of over the place in terms of arranging atoms and assigning lone pairs. I always count valence electrons first, but if anybody has tips on the order they do stuff afterwards, that wou...
by Ariel Fern 2B
Sun Oct 27, 2019 11:15 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Drawing Orbitals and Electron Spins
Replies: 2
Views: 55

Drawing Orbitals and Electron Spins

When a question asks to write the electron configuration, it is typically asking for just the subshells and the number of electrons within the subshell. I was wondering under what context would we also have to draw out the orbitals and arrows representing the electron spins: Would the question just ...
by Ariel Fern 2B
Sun Oct 27, 2019 11:07 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent bonds and cations
Replies: 3
Views: 46

Re: Covalent bonds and cations

Since the ionization energy is higher for non-metals, this means that it takes much more energy for an electron to remove an electron from an atom and allow it to become a positive cation. Rather than expend the energy releasing electrons to form a full outer valence shell, the atoms would rather el...
by Ariel Fern 2B
Sun Oct 27, 2019 11:03 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 4f Subshell Clarification
Replies: 3
Views: 72

Re: 4f Subshell Clarification

Thank you for responding! That definitely makes sense; I wasn't thinking of Aufbau's Principle originally so now it is much more clear!
by Ariel Fern 2B
Sun Oct 27, 2019 11:02 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Memorizing the Equation
Replies: 4
Views: 86

Memorizing the Equation

Anybody have any tips to memorizing the Formal Charge equation? Or should I just keep practicing it to become "second nature?" I honestly keep having to reference my notes right now, so if anybody has tips for formal charge calculations or memorizing the equation, that would be great! Than...
by Ariel Fern 2B
Sun Oct 27, 2019 7:46 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 4f Subshell Clarification
Replies: 3
Views: 72

4f Subshell Clarification

On question 1E.13, it asks for the electron configuration of Tungsten, which has 14 electrons in the 4f subshell. I just had some clarifications about this subshell: it fills up before the 5d subshell, right? And does the 4f subshell always have 14 electrons automatically? It seems like all of the t...
by Ariel Fern 2B
Sun Oct 27, 2019 7:22 pm
Forum: Ionic & Covalent Bonds
Topic: Charges
Replies: 4
Views: 61

Re: Charges

I was definitely confused about this too because if you think of the numbers of protons and electrons per atom; it doesn't come out right since electrons are being shared. Like was said, you have to think of the molecule as a whole and consider the valence electrons and how much is needed to have fu...
by Ariel Fern 2B
Sat Oct 19, 2019 10:34 pm
Forum: Quantum Numbers and The H-Atom
Topic: Positive Sign on the Magnetic Quantum Number
Replies: 2
Views: 60

Positive Sign on the Magnetic Quantum Number

Hi everyone! I was just wondering if the + sign on the magnetic quantum number (m l ) is mandatory or if it is just good practice. The answers in the book have the + sign, so I was just wondering if it was necessary or if writing 2 was fine as opposed to +2. Thanks! I'll probably include the + sign ...
by Ariel Fern 2B
Sat Oct 19, 2019 10:25 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: H-Atom's Spectral Lines
Replies: 1
Views: 63

Re: H-Atom's Spectral Lines

Hi Anisha! The Balmer and Lyman Series refers to transitions back to the lower energy levels (n=1 & n=2, respectively). These electrons emit energy because they are going from a higher energy level to a lower one. Therefore, the electron in the H-atom could occupy a space in the n=6 energy level...
by Ariel Fern 2B
Sat Oct 19, 2019 10:13 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Resources
Replies: 2
Views: 60

Re: Resources

Hi Matt! It's Ariel!

Which resource are you referring to? I believe the Sapling Learning and Ebook needs an Access Code that you need to pay for, not sure though. But all the tutoring sessions/workshops, office hours, and Chemistry Community are for sure free!
by Ariel Fern 2B
Sat Oct 19, 2019 9:50 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Letter Names
Replies: 4
Views: 68

Re: Letter Names

The letters themselves represent a word. S represents sharp, p represents principal, f represents fundamental and d represents diffuse.Thi sis from the spectra of the alkali metals. That's interesting to learn! Honestly, I've been looking at the letters for so long but haven't really considered wha...
by Ariel Fern 2B
Sat Oct 19, 2019 9:06 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Shell, Subshell, Orbital Terminology
Replies: 8
Views: 167

Shell, Subshell, Orbital Terminology

Just wanted to share a clarification on something I used to mix up all the time. Shells refer to the principal quantum number (n); subshells refer to the angular momentum quantum number (l); and orbitals refer to the magnetic quantum number/subshell orientation (m l ). When something is referred to ...
by Ariel Fern 2B
Sun Oct 13, 2019 11:25 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Lyman, Balmer, Paschen, & Bracket Series?
Replies: 4
Views: 72

Re: Lyman, Balmer, Paschen, & Bracket Series?

Thank you all! That makes more sense; I guess I was just thinking of only transitions from adjacent shells - it makes more sense to consider the transitions from the other shells as well. Thanks!
by Ariel Fern 2B
Sun Oct 13, 2019 6:09 pm
Forum: Photoelectric Effect
Topic: Energy of Photon Clarification
Replies: 4
Views: 105

Re: Energy of Photon Clarification

FDeCastro_1B wrote:Yes! E(photon) should always be greater than or equal to the work function in order to eject an electron.


Thank you so much! This gives me peace of mind that I didn't copy down the notes wrong or misunderstand the lecture, haha!
by Ariel Fern 2B
Sat Oct 12, 2019 9:16 pm
Forum: Properties of Light
Topic: Equations We’ve Learned So Far
Replies: 11
Views: 258

Re: Equations We’ve Learned So Far

It's important to distinguish between equations that are relevant to light (EM radiation) and quantum movement of electrons. For light specifically, you should pay attention to: These two equations are applied to light in the theory that light is a wave: c = λv = 3*10^8 (speed of light = wavelength...
by Ariel Fern 2B
Sat Oct 12, 2019 9:05 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Lyman, Balmer, Paschen, & Bracket Series?
Replies: 4
Views: 72

Lyman, Balmer, Paschen, & Bracket Series?

Hi everyone! Can somebody help me understand what exactly these series are referring to? I know that generally it's about electrons emitting energy/photons when excited when moving between quantum levels, but I don't understand how all of these series relate to energy levels (n=1, 2, 3, 4...) as the...
by Ariel Fern 2B
Sat Oct 12, 2019 8:46 pm
Forum: Photoelectric Effect
Topic: Energy of Photon Clarification
Replies: 4
Views: 105

Energy of Photon Clarification

In the lecture notes, it states that: "(E = hv) - Work Function = (Ek = 1/2 mv^2), UNLESS... E(photon) > E(Energy Remove e-) then e- not emitted even for high intensity light If light had only wave properties, then increasing intensity should eject e-" This E(photon) is referring to a ligh...
by Ariel Fern 2B
Sat Oct 12, 2019 8:14 pm
Forum: Properties of Light
Topic: Equations We’ve Learned So Far
Replies: 11
Views: 258

Re: Equations We’ve Learned So Far

Hi Ellis! This is Ariel. Here's a general list from my notes: c = λ ν -- Used to calculate wavelength/frequency E(photon) = h ν -- Used to calculate energy per single photon -- Bohr Frequency Condition: v = ∆E/h; used to calculate frequency E(photon) = Work Function/Threshold Energy + EK EK =(1/2)mv...
by Ariel Fern 2B
Mon Oct 07, 2019 5:01 pm
Forum: Limiting Reactant Calculations
Topic: Different Way to Find the Limiting Reactant
Replies: 3
Views: 103

Re: Different Way to Find the Limiting Reactant

Hi Petrina and Ishaa!

I'm glad to hear that this has helped and is another viable option for you! If the problem gives the quantities in grams, then I convert grams into moles by dividing by molar mass, which then allows me to use the method! Hope that makes sense!

Go to advanced search