Search found 109 matches

by sbeall_1C
Sat Mar 14, 2020 7:35 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: HW 7.17
Replies: 1
Views: 15

Re: HW 7.17

A catalyst, unlike an intermediate, can be included in the rate law, so if a catalyst is in the rate determining step, it can affect the overall rate law, I believe.
by sbeall_1C
Sat Mar 14, 2020 7:33 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Profile
Replies: 2
Views: 74

Re: Reaction Profile

I don't think we have enough information to determine how large of a dip there should be, but as long as we show that the energy decreases and then increases again, we should be good!
by sbeall_1C
Sat Mar 14, 2020 7:32 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: 7B 3(c)
Replies: 2
Views: 68

Re: 7B 3(c)

I am also slightly confused by this question, but what I think is happening is that we are given an initial concentration of A as 0.153 M, and then we use the information that after 115s, there is 0.024 mol B. Since B is a product, we had to have used some of the A to form B, so we have to subtract ...
by sbeall_1C
Sat Mar 14, 2020 7:19 pm
Forum: General Rate Laws
Topic: 7A.11( part b)
Replies: 1
Views: 56

Re: 7A.11( part b)

Hi! For this question, the overall reaction is second order, but each individual reactant is first order. Therefore, doubling the concentration of H2 will only double the rate or reaction. You are right that if H2 were by itself second order, it would quadruple the rate; however, the order of reacti...
by sbeall_1C
Sat Mar 14, 2020 7:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kw and other constants
Replies: 9
Views: 133

Re: Kw and other constants

The w refers to water, so the equilibrium constant for water is 1.0x10-14. Ka and Kb multiply to Kw because water is neutral. The case of the w (upper case or lower) does not matter, I don't think, it is merely there to indicate this specific constant for water.
by sbeall_1C
Sat Mar 14, 2020 7:14 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: endgame 5
Replies: 1
Views: 77

Re: endgame 5

For number 5, it is specially asking us to find the Ka value of HF, meaning we must treat HF as an acid. Therefore, HF will have to be the reactant and the half reaction involving HF must be flipped despite its larger standard cell potential. Usually, we flip the lower cell potential to result in a ...
by sbeall_1C
Sat Mar 14, 2020 7:11 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Final Review
Replies: 2
Views: 105

Re: Final Review

I'm not sure if this is the what you are getting at, but when there are intermediates in the rate-determining step (i.e the slow step), you need to replace the intermediates with the correct reactants to match the determined rate law. In order to do this, you need to solve for the intermediates usin...
by sbeall_1C
Wed Mar 11, 2020 4:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 11
Views: 61

Re: salt bridge

In a Galvanic cell, electrons flow form the anode to the cathode which results in solutions holding charges. The anode will become positive as it loses electrons, and the cathode solution will becomes more negative as it gains electrons. The salt bridge is put in place to neutralize the solutions. T...
by sbeall_1C
Sun Mar 08, 2020 11:05 pm
Forum: Van't Hoff Equation
Topic: What's the purpose of Van't Hoff?
Replies: 5
Views: 116

Re: What's the purpose of Van't Hoff?

The Van't Hoff equation allows you to calculate the equilibrium constant or temperature of an equation using another equation.

It is derived using the equations Detla G=deltaH-TdeltaS and deltaG=-RTlnK. Putting these together gives you the van't Hoff equation!
by sbeall_1C
Sun Mar 08, 2020 10:55 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Speed of a reaction
Replies: 2
Views: 33

Re: Speed of a reaction

Generally, if a reaction occurs in multiple steps, the slow reaction is the rate-determining step. So, if the rate law is given, look at the multistep reaction and find which reaction corresponds to the rate law, and this will be the slow reaction and the remaining reactions fast. I also think that ...
by sbeall_1C
Sun Mar 08, 2020 10:52 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Work max
Replies: 4
Views: 87

Re: Work max

Delta G refers to the energy available to do work, so the maximum work that can be done is equal to energy available to do that work!

I don't believe there are any exceptions to this rule!
by sbeall_1C
Sun Mar 08, 2020 10:50 pm
Forum: First Order Reactions
Topic: Derivation of Integrated Rate Laws
Replies: 1
Views: 18

Re: Derivation of Integrated Rate Laws

The Integrated rate laws help you determine if the reaction is zero, first, or second order reactions when graphed, as the integrated laws represent linear functions. I do not believe you need to know how to derive them as the equations are listed on the constants sheet, but it is good to have a bas...
by sbeall_1C
Sun Mar 08, 2020 10:47 pm
Forum: Ideal Gases
Topic: When do we change PV=NRT into deltas?
Replies: 4
Views: 78

Re: When do we change PV=NRT into deltas?

If you change a variable on one side of the equation to a delta, so either delta P or delta T, you have to change a variable on the other side of the equation, so it would either be delta T or delta n. There cannot be a delta R as this is a constant. You can use the information given in the problem ...
by sbeall_1C
Sun Mar 01, 2020 4:55 pm
Forum: Balancing Redox Reactions
Topic: H+ or H2O
Replies: 4
Views: 46

Re: H+ or H2O

In an acidic solution, you would use H2O to balance the oxygen, and you would use H+ to balance the Hydrogen. In a basic solution, you use H2O to balance the O and the H, but when you add water molecules to one side of the reaction to balance Hydrogen, you have to add the same number of hydroxide OH...
by sbeall_1C
Sun Mar 01, 2020 4:52 pm
Forum: Administrative Questions and Class Announcements
Topic: HW 9
Replies: 5
Views: 71

Re: HW 9

Test 9 is covering the last page of the thermodynamics syllabus and the electrochemistry syllabus.

This refers to HW problems:
5G: 13, 15, 17, 19, 21
5J: 11,13, 15
5.55, 5.61

And all the HW probs outlined on the electrochemistry syllabus (Focus 6K-6O.1)
by sbeall_1C
Sun Mar 01, 2020 4:48 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Deriving the Nernst Equation
Replies: 3
Views: 58

Re: Deriving the Nernst Equation

Hey! I think you are correct in your thought process. You just have to make sure that is you are using standard conditions for delta G, you use standard conditions for the remaining variables and this yields the standard cell potential. I believe as long as you are consistent, you can use both delta...
by sbeall_1C
Sun Mar 01, 2020 4:45 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cell potential
Replies: 15
Views: 121

Re: cell potential

When the Cell Potential is positive, this refers to a negative delta G and therefore a spontaneous reaction which proceed over time, not necessarily in a fast manner.
by sbeall_1C
Sun Mar 01, 2020 4:44 pm
Forum: Balancing Redox Reactions
Topic: moles of electrons transferred
Replies: 4
Views: 31

Re: moles of electrons transferred

You can look at the change in charge of a species or look for the change in oxidation numbers of a species from reactants to products! This will relate to the number of moles of electrons transferred.
by sbeall_1C
Sun Feb 23, 2020 7:27 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6L.5 b)
Replies: 5
Views: 44

Re: 6L.5 b)

At times, you will have to use an inert conductor such as platinum as en electrode to transfer electrons!
by sbeall_1C
Sun Feb 23, 2020 7:23 pm
Forum: Balancing Redox Reactions
Topic: Oxidation Numbers- How to Find
Replies: 3
Views: 37

Re: Oxidation Numbers- How to Find

There are certain oxidation numbers attached to certain elements, and these do not differ between reaction so you can use these known values to determine unknown ones, such as the oxidation numbers of transition metals which tend to vary according to the compound that they are present in. For exampl...
by sbeall_1C
Sun Feb 23, 2020 7:19 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cell Notation
Replies: 3
Views: 55

Re: Galvanic Cell Notation

In certain cases, you would add a solid agent. Dr. Lavelle mention platinum in class!
by sbeall_1C
Wed Feb 12, 2020 3:42 pm
Forum: Phase Changes & Related Calculations
Topic: internal energy
Replies: 2
Views: 102

Re: internal energy

Constant temperature (isothermal) indicates that delta U is 0. Constant pressure allows you to set q equal to delta H, and the work is -PdeltaV.
by sbeall_1C
Sun Feb 09, 2020 10:29 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: positive-negative entropy
Replies: 1
Views: 22

Re: positive-negative entropy

When a system can take more possible states, the entropy is greater. For example, a gas which has more space to take different states, the entropy is greater than say a solid, whose particles are more confined to fewer possible states.
by sbeall_1C
Sun Feb 09, 2020 10:25 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat Capacity
Replies: 5
Views: 40

Re: Specific Heat Capacity

You use specific heat capacity when the mass is given in grams. You can use q=mCdeltaT, where C is specific heat capacity. You can use q=nCdeltaT when the C is molar heat capacity.
by sbeall_1C
Sun Feb 09, 2020 10:23 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: q rev
Replies: 4
Views: 56

Re: q rev

A system undergoes reversible expansion when the change is made with infinitesimal changes to pressure. In a irreversible expansion, the change cannot be undone, and the reaction proceeds with a constant external pressure.
by sbeall_1C
Sun Feb 09, 2020 10:21 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: m and n in heat capacity
Replies: 4
Views: 35

Re: m and n in heat capacity

When you refer to the mass in grams, you will use specific heat capacity, which is J per gram degree celsius, so we multiplying you are left with J. When you use moles, you will use the molar heat capacity in the equation, which is in J per mol degree celsius, so once again you are left with J.
by sbeall_1C
Sun Feb 09, 2020 10:19 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Ideal Gasses
Replies: 2
Views: 30

Re: Ideal Gasses

Unless otherwise, I believe we assume the gases we are dealing with behave in an ideal manner, following PV=nRT.
by sbeall_1C
Sun Feb 02, 2020 10:30 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: State Function
Replies: 4
Views: 37

Re: State Function

Internal energy does not depend on the path a reactions takes. It describes an equilibrium state of a thermodynamic system.
by sbeall_1C
Sun Feb 02, 2020 10:26 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work and Heat
Replies: 2
Views: 15

Re: Work and Heat

Work and heat are dependent functions, and they only appear when a change occurs to a system, therefore they are not state functions.
by sbeall_1C
Sun Feb 02, 2020 10:16 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Steam burns
Replies: 8
Views: 71

Re: Steam burns

If you look at a phase change graph, you will see that the change between liquid and gas is represented by a straight line in which heat is increasing but the substance has not yet changed phases. Therefore, steam holds a greater temperature.
by sbeall_1C
Sun Feb 02, 2020 10:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test 1
Replies: 3
Views: 61

Re: Test 1

I got mine back in my discussion in week 4! If you did not get yours back, I'm sure you will get it back this week!
by sbeall_1C
Sun Feb 02, 2020 10:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State Property
Replies: 5
Views: 49

Re: State Property

Enthalpy is a state property, meaning that it is a value that does not depend on the path taken to achieve a certain value, only that value in a certain instant. For example, think of a mountain and an object. An object will be a certain height up the mountain regardless of how that height was achie...
by sbeall_1C
Sun Jan 26, 2020 11:04 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: State Functions
Replies: 4
Views: 42

Re: State Functions

Heat and work are not state functions, but enthalpy is a state function!
by sbeall_1C
Sun Jan 26, 2020 11:03 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: delta s
Replies: 5
Views: 42

Re: delta s

Delta s is entropy!
Delta H is enthalpy!
by sbeall_1C
Sun Jan 26, 2020 2:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: clarification from lecture - "state function"
Replies: 2
Views: 24

Re: clarification from lecture - "state function"

A state function describes a system at a given instant but is not dependent on how that current state was achieved. A state function depends only on the final and initial state but not the path that was taken. I believe in class Dr. Lavelle one over an example involving a mountain to discuss this id...
by sbeall_1C
Sun Jan 26, 2020 2:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Lewis Structures Method 2
Replies: 6
Views: 55

Re: Lewis Structures Method 2

It is not necessary, but it will help you to visualize how many bonds are broken on the reactant side and how many are formed on the product side.
by sbeall_1C
Sun Jan 26, 2020 2:25 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Changes endo/exo
Replies: 3
Views: 24

Re: Phase Changes endo/exo

Yes, some phase changes are exothermic. If you go from a system of higher energy to a system of lower energy, it will be an exothermic reactions. For example, going from a gas to a liquid in vaporization (or commonly called condensation) reaction, it is exothermic because the gas has a higher energy...
by sbeall_1C
Sun Jan 19, 2020 11:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Clarification on these statements
Replies: 2
Views: 27

Re: Clarification on these statements

Both of those statements mean the same. If to maintain equilibrium, the reaction will proceeds to the right, that means more products will be formed which can also be stated with equilibrium lies to the right.
by sbeall_1C
Sun Jan 19, 2020 11:28 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's principle
Replies: 7
Views: 58

Re: Le Chatelier's principle

Le Chatelier's principle explains what a reaction will do to maintain equilibrium when the conditions are altered. If more reactant is added to the system, the reaction will proceed towards the products to maintain equilibrium. Keep in mind that the equilibrium constant is a constant ratio between p...
by sbeall_1C
Sun Jan 19, 2020 11:24 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Endothermic Reaction.
Replies: 7
Views: 63

Re: Endothermic Reaction.

Usually, the delta H value will be given. If this value is positive, it is an endothermic reaction. If this value is negative, it is an exothermic reaction because heat is being given off. Endothermic reactions require energy to proceed, so if a reactant is held tightly together through strong inter...
by sbeall_1C
Sun Jan 19, 2020 11:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: identifying acids & bases
Replies: 5
Views: 50

Re: identifying acids & bases

The acid is the molecule that donates and H+ tp form H3O+, whereas a base is a substance that accepts an H+ and forms OH- as products. The conjugate acid/base form as a result of the transfer of H+. For example, HCl+H2O-->H3O+ + Cl-. This is an example of an acid donating an H+. HCl is the acid, H2O...
by sbeall_1C
Sun Jan 19, 2020 11:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Applying Kw
Replies: 2
Views: 31

Re: Applying Kw

Ba2+ is the cation of a strong base, so when it dissociates it will not affect the pH of the solution. Kw refers to the equilibrium constant for water, and shows how water has a neutral pH of 7. So the OH will increase the pH which changes the Kb and therefore allows us to calculate the Ka using Kw=...
by sbeall_1C
Fri Jan 17, 2020 1:05 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Homework question 5J.5
Replies: 3
Views: 34

Homework question 5J.5

For question 5J.5, many reactions are given and we are asked to predict whether the reactants or products would be favored with an increase in total pressure. One of the reactions is 2HD(g)+H2(g)⇌D2(g). The answer says no change, but wouldn't the reaction favor the products because there are less mo...
by sbeall_1C
Sun Jan 12, 2020 6:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reaction Quotient Q
Replies: 6
Views: 38

Re: Reaction Quotient Q

Q is calculated when an equation is not at equilibrium, whereas K uses equilibrium values!
by sbeall_1C
Sun Jan 12, 2020 6:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: memorization
Replies: 12
Views: 126

Re: memorization

I do not believe we will have to memorize any K values. Dr. Lavelle will provide us any values we need to know.
by sbeall_1C
Sun Jan 12, 2020 6:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Example 5I.3 (page 556 on pdf)
Replies: 3
Views: 26

Re: Example 5I.3 (page 556 on pdf)

Removing these x terms makes the solving easier, if you do not want to use the Quadratic equation. If the change in concentration/pressure (x) is less than 5% of the initial value, you can remove the x terms as the values will be so small that they do not affect the final answer. You have to make su...
by sbeall_1C
Sun Jan 12, 2020 6:21 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Application of La Chatelier's
Replies: 3
Views: 23

Re: Application of La Chatelier's

You apply Le Chatelier's principle in problems that ask you which way a reaction will proceed to maintain equilibrium. If a reactant is added, the reaction will proceed toward the products to maintain equilibrium, and vice versa. Remember that K is a constant ration of products over reactants.
by sbeall_1C
Sun Jan 12, 2020 6:19 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q>K
Replies: 9
Views: 74

Re: Q>K

Q is calculated using non-equilibrium values. If Q>K, that means that the reaction will proceed to the left, or toward the reactants, to reach equilibrium. The products will be used up to produce more reactants, which in turn will raise the values for the reactants and lower the Q value until Q=K an...
by sbeall_1C
Sun Jan 12, 2020 6:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K units
Replies: 3
Views: 26

Re: K units

There is no unit for K, it is a unites value. If you were to include units for every value used to calculate K, the units would all cancel, which leaves K without any units!
by sbeall_1C
Sun Jan 12, 2020 6:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K and Q
Replies: 10
Views: 70

Re: K and Q

K and Q are calculated in the same way, except that K uses the values from equilibrium and Q uses initial conditions/conditions not at equilibrium. You can use the value of Q to determine which way the the reaction will proceed to reach equilibrium!
by sbeall_1C
Sun Jan 12, 2020 6:13 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating K
Replies: 9
Views: 68

Re: Calculating K

K does not include pure liquids or solids, merely aqueous solutions and gases!
by sbeall_1C
Sat Dec 07, 2019 6:20 pm
Forum: Biological Examples
Topic: Vitamin B12
Replies: 1
Views: 43

Re: Vitamin B12

Hey! I am not sure what the ligands are, but I know that the transition metal of Vitamin B12 is Cobalt!
by sbeall_1C
Sat Dec 07, 2019 6:15 pm
Forum: Conjugate Acids & Bases
Topic: chemical equations of acids and bases
Replies: 2
Views: 93

Re: chemical equations of acids and bases

Hey! You use a reverse arrow when the reaction does not involve a strong acid or a strong base! When a strong acid or base is present, you use a single sided arrow because the acid/base dissociates basically completely.
by sbeall_1C
Sat Dec 07, 2019 6:14 pm
Forum: Naming
Topic: Naming coordination compounds
Replies: 2
Views: 35

Re: Naming coordination compounds

I do not believe we will be getting the chart! He said we should know everything on the chart though!
by sbeall_1C
Sat Dec 07, 2019 6:13 pm
Forum: Naming
Topic: Oxalate Compound
Replies: 1
Views: 30

Re: Oxalate Compound

I believe the name would be sodium trisoxalatocobaltate(III).

Since oxalate is bidentate, you use -tris instead of -tri, and since the overall charge of the coordination complex is negative, you add -ate to the name of the transition metal.
by sbeall_1C
Sat Dec 07, 2019 6:10 pm
Forum: Student Social/Study Group
Topic: amphoteric vs. amphiprotic
Replies: 4
Views: 153

Re: amphoteric vs. amphiprotic

Amphoteric means that a certain molecule can act as either an acid or a base, whereas amphiprotic means that a proton can either be accepted or donated. Amphiprotic implies amphoteric, but amphoteric does not imply amphiprotic.
by sbeall_1C
Sat Dec 07, 2019 5:09 pm
Forum: Conjugate Acids & Bases
Topic: Reaction arrows
Replies: 3
Views: 104

Re: Reaction arrows

Hey! You use a reverse arrow when the reaction does not involve a strong acid or a strong base! When a strong acid or base is present, you use a single sided arrow because the acid/base dissociates basically completely.
by sbeall_1C
Sat Dec 07, 2019 4:52 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 1
Views: 51

Polydentate

Is Carbonate considered bidentate like oxalate? If it is, is it due to that negatively charged oxygen atoms or is there another reason?
by sbeall_1C
Sun Dec 01, 2019 11:23 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Trichloroacetic acid
Replies: 2
Views: 46

Re: Trichloroacetic acid

Trichloroacetic acid is stronger than acetic acid because the chlorine atoms have higher electronegativity!
by sbeall_1C
Sun Dec 01, 2019 11:22 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: pka v. ka
Replies: 4
Views: 73

Re: pka v. ka

The difference between pKa and Ka is that the pKa is the negative logarithm of Ka. The lower the Ka value, the greater the pKa value, and therefore the stronger the acid.
by sbeall_1C
Sun Dec 01, 2019 11:18 pm
Forum: Lewis Acids & Bases
Topic: Long bonds vs Short bonds?
Replies: 9
Views: 159

Re: Long bonds vs Short bonds?

Long bonds are weaker than short bonds because the nuclei are farther apart so there exists less attractive pull. It is easier to break apart a bond when the atoms are farther apart.
by sbeall_1C
Sun Dec 01, 2019 11:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determing Coordination Number
Replies: 5
Views: 44

Re: Determing Coordination Number

I believe that the coordination number refers to the number of bonds within a complex. The example in class was [Fe(CN)6]4- has a coordination number of 6, as there are 6 bonds.
by sbeall_1C
Sun Dec 01, 2019 11:08 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Conjugate Seesaw
Replies: 1
Views: 24

Re: Conjugate Seesaw

I believe the concept of conjugate seesaw refers to how if you have a really strong acid, it would make a weak conjugate base, and if you had a strong base, it would make a weak conjugate acid.
by sbeall_1C
Sun Dec 01, 2019 11:06 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Class wed 11/27
Replies: 7
Views: 90

Re: Class wed 11/27

Dr. Lavelle went over pH and pOH in greater detail, and how to derive the pH scale! If you read the section on acid and base naturalization and the relationship between pH, pOH, and pKa, you should be good!
by sbeall_1C
Sun Nov 24, 2019 2:40 pm
Forum: Naming
Topic: Homework problems Week 9
Replies: 4
Views: 46

Re: Homework problems Week 9

Hey!

Yes, I believe you can turn in homework form Focus 9C. As long as the problems you are doing relate to what we are learning in class and are not from sections from completely different topics/outlines, you should be good!
by sbeall_1C
Sun Nov 24, 2019 2:38 pm
Forum: Naming
Topic: Chemistry Community
Replies: 4
Views: 68

Re: Chemistry Community

Hi! If you are struggling with finding ways to interact on Chemistry Community, it may be beneficial to log on every time you are doing homework or reading the textbook or going over lecture notes, and anytime you question something, post it! It may be easier for you to post a question a day, or try...
by sbeall_1C
Sun Nov 24, 2019 2:26 pm
Forum: Dipole Moments
Topic: Hydrogen bonding
Replies: 5
Views: 106

Re: Hydrogen bonding

Do they F, O, and N atoms on a separate molecule have to be bonded directly to a H atom for Hydrogen bonding to be able to occur? For example, in benzoic acid C6H5COOH, there is an O doubled bonded to a C, so the O is not directly bonded to an H. Can this particular O still participate in Hydrogen b...
by sbeall_1C
Sun Nov 24, 2019 2:19 pm
Forum: Hybridization
Topic: Lone pairs
Replies: 9
Views: 113

Re: Lone pairs

Hi!

Lone pairs are electron groups and therefore they must affect hybridization, just like they affect shape and bond angles!
by sbeall_1C
Sun Nov 24, 2019 2:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: H3O+
Replies: 11
Views: 6534

Re: H3O+

Hi!

H3O+ has a molecular geometry of tetrahedral, since there are 4 regions of electron density surrounding the central O atom (3 Hydrogens and 1 lone pair of electrons). The VSEPR shape would be trigonal pyramidal.
by sbeall_1C
Sun Nov 17, 2019 9:08 pm
Forum: Student Social/Study Group
Topic: Test 2
Replies: 11
Views: 147

Re: Test 2

Only the first slide or two (the first 5 minutes of class) will be on the test! The entirety of the lecture will not be on the test.
by sbeall_1C
Sun Nov 17, 2019 9:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Radicals
Replies: 2
Views: 32

Re: Radicals

I believe that radical electrons repel in a way similar to a pair of lone pairs, but to a weaker extent because the electron density cloud will be smaller for a single electron. The repulsion is still present and can affect bond angles, but merely to a lesser extent.
by sbeall_1C
Sun Nov 17, 2019 9:04 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: induced dipole
Replies: 4
Views: 40

Re: induced dipole

An induced dipole occurs when a molecule that would not usually possess a dipole forms a dipole due to integration with a molecule containing a dipole. For example, the polarity of HF induces a dipole in N2, a usually non polar molecule. The permanent dipole moment induces a dipole moment, and this ...
by sbeall_1C
Sun Nov 17, 2019 9:00 pm
Forum: Student Social/Study Group
Topic: Test 2
Replies: 11
Views: 147

Re: Test 2

Dr. Lavelle also said he will covering sigma and pi bonds in more depth for the first 5 minutes of class tomorrow and that will be on Test 2!
by sbeall_1C
Sun Nov 17, 2019 8:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape of H20
Replies: 3
Views: 58

Re: Molecular Shape of H20

H2O has a bent molecular shape rather than a linear shape because the two pairs of lone pair electrons take up more space than a bond, and the electron repulsion pushes away from the atoms to create bond angles less than 180 degrees but rather less than 109.5. The Lone pair electrons will not stay i...
by sbeall_1C
Sun Nov 17, 2019 8:55 pm
Forum: Hybridization
Topic: Pi and sigma bonds
Replies: 4
Views: 73

Re: Pi and sigma bonds

Sigma bonds refer to the s-orbital, and occur when two orbitals are overlapping end to end. Sigma bonds have no nodal planes containing the internuclear axis. This is the reason why a single bond contains one sigma bond. A pi bond refers to a p-orbital, and occurs when two orbitals overlap side to s...
by sbeall_1C
Sun Nov 10, 2019 5:59 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Graph of energy levels
Replies: 1
Views: 145

Re: Graph of energy levels

The graph of an electron rising/falling has Energy on the y-axis (and the Energy is negative, building up to E=0). The principal energy levels are drawn parallel to the x-axis (n=1, =2, n=3,..., n= Infinity). To solve for the change in principal energy levels, you need to look for clues in the quest...
by sbeall_1C
Sun Nov 10, 2019 5:46 pm
Forum: Octet Exceptions
Topic: Reasoning for Octet Exception
Replies: 11
Views: 356

Re: Reasoning for Octet Exception

Yes, it is because of the presence of the d-orbital in the elements staring in period 3! This d-orbital can accommodate the extra electrons! If you look at the formal charge for the elements you mentioned (Si, P, S, and Cl) you can see that having more than the octet minimizes the formal charge and ...
by sbeall_1C
Sun Nov 10, 2019 5:38 pm
Forum: Administrative Questions and Class Announcements
Topic: Workshop Sessions
Replies: 1
Views: 40

Re: Workshop Sessions

Yes, I believe the workshops and step-ups will continue for the entire quarter!
by sbeall_1C
Sun Nov 10, 2019 5:35 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 4
Views: 63

Re: Test 2

I am not 100% sure what Test 2 will cover, but as the test is coming up the week of November 19th, I am assuming the test will cover the remainder of Outline 3: Chemical Bonds, and the Outline 4: Molecular Shape and Structure. Dr. Lavelle will let us know for sure sometime soon, I believe!
by sbeall_1C
Tue Nov 05, 2019 8:52 pm
Forum: Resonance Structures
Topic: Resonance structures for (NH2)COCH3 [ENDORSED]
Replies: 1
Views: 90

Resonance structures for (NH2)COCH3 [ENDORSED]

In the workshop worksheet from 11/3 with Karen, a question asked, "Experiments indicate that two resonance structures exist for the organic molecule, (NH2)COCH3. Draw them." Why would this molecule form a resonance structure by making Nitrogen radical? Why is it necessary to have a resonan...
by sbeall_1C
Sun Nov 03, 2019 7:10 pm
Forum: Lewis Acids & Bases
Topic: diff b/w lewis acid and base
Replies: 12
Views: 164

Re: diff b/w lewis acid and base

A Lewis acid accepts an electron pair, and a Lewis base donates a pair of electrons!
by sbeall_1C
Sun Nov 03, 2019 7:09 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Question on Atomic Spectrum Post Assessment
Replies: 3
Views: 57

Re: Question on Atomic Spectrum Post Assessment

For this question, would you make the energy you calculate from the given frequency negative because it is being emitted?
by sbeall_1C
Sun Nov 03, 2019 7:04 pm
Forum: Lewis Structures
Topic: Lewis Structures and Polarity
Replies: 1
Views: 31

Re: Lewis Structures and Polarity

Hi! You can label the dipoles and polarity on a Lewis structure by using an arrow pointing toward the more negative atom, as the electron is being pulled toward that atom, and is creating a negative charge on that atom. I don't believe that polarity directly affects the drawing of Lewis structures a...
by sbeall_1C
Sun Nov 03, 2019 6:52 pm
Forum: Resonance Structures
Topic: Resonance structures
Replies: 15
Views: 346

Re: Resonance structures

Resonance structures are when you move electrons within a Lewis structure (such as moving double bonds) to stabilize the structure and delocalize the electrons. The true structure of a Lewis Structure with resonance is a hybrid of all the possible resonance structures.
by sbeall_1C
Sun Nov 03, 2019 6:50 pm
Forum: Formal Charge and Oxidation Numbers
Topic: The equation
Replies: 3
Views: 60

Re: The equation

Hi!
A lone pair of electrons refers to the electrons that are not involved in bonding when drawing the Lewis structures!
by sbeall_1C
Sun Nov 03, 2019 6:47 pm
Forum: Properties of Electrons
Topic: Photoelectric effect
Replies: 5
Views: 238

Re: Photoelectric effect

Khan Academy always has really helpful videos, so it is worth checking that out!
by sbeall_1C
Sun Oct 27, 2019 2:33 pm
Forum: Ionic & Covalent Bonds
Topic: He
Replies: 3
Views: 46

Re: He

The electron configuration of He is 1s2. When drawing the Lewis structure, you would put these electrons together to show how they are in the same sub shell of the atom. If the valence electrons appear in different sub shells, such as the s and p, you keep the s electrons together and then separate ...
by sbeall_1C
Sun Oct 27, 2019 2:28 pm
Forum: Lewis Structures
Topic: Anion/Cations
Replies: 2
Views: 46

Re: Anion/Cations

Traditionally, a Lewis structure of a cation or an anion will be put in brackets and the charge will be placed in the top right corner outside the bracket. For example, sulfate will have a 2- charge written outside the bracket surrounding the Lewis structure to indicate that the structure is not neu...
by sbeall_1C
Sun Oct 27, 2019 2:25 pm
Forum: Trends in The Periodic Table
Topic: Cations
Replies: 8
Views: 120

Re: Cations

Cations are smaller because these atoms have a positive charge on their central nucleus, which means that there are more protons than electrons. The positive charge pulls the electrons closer to the nucleus than if there were to be a neutral nucleus. This greater attraction leads to a smaller atomic...
by sbeall_1C
Sun Oct 27, 2019 2:23 pm
Forum: Student Social/Study Group
Topic: Miderm Review
Replies: 10
Views: 256

Re: Miderm Review

I am not sure if Dr. Lavelle directly gives study guides, but at the Workshops the UAs give worksheets that go over the concepts. I think these are very helpful, especially to review for the midterm!
by sbeall_1C
Sun Oct 27, 2019 2:20 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 8
Views: 73

Re: Resonance

Resonance structures show the possible ways that elements can be bonded. By drawing all possible combinations (such as single, double, triple bonds), we can calculate the formal charge of each configuration to find the most stable arrangement.
by sbeall_1C
Sun Oct 27, 2019 2:17 pm
Forum: Ionic & Covalent Bonds
Topic: Valence Electrons
Replies: 4
Views: 47

Re: Valence Electrons

Valence electrons are the electrons in the outermost shell of an atom that are involved in reactions. Transition metals most commonly have 2 valence electrons, such as 4s2 or 5s2. The d electrons are used to write the electron configuration, but may not be used to find valence electrons.
by sbeall_1C
Sun Oct 20, 2019 8:40 pm
Forum: Trends in The Periodic Table
Topic: Study Buddies?
Replies: 8
Views: 105

Re: Study Buddies?

That would be awesome! My email is shannonbeall@yahoo.com.
by sbeall_1C
Sun Oct 20, 2019 8:38 pm
Forum: *Black Body Radiation
Topic: Understanding Black Body Radiation
Replies: 6
Views: 175

Re: Understanding Black Body Radiation

Also, studies of black body radiation led to Planck's hypothesis of the quantization of electromagnetic radiation, which the photoelectric effect then provides evidence of the particle like properties of electromagnetic radiation. Black body radiation, therefore, helped guide research toward discove...
by sbeall_1C
Sun Oct 20, 2019 5:03 pm
Forum: Quantum Numbers and The H-Atom
Topic: Difference in Quantum Numbers?
Replies: 2
Views: 37

Re: Difference in Quantum Numbers?

The principal quantum number (n) refers to which energy level the electron is in (n=1,2,3,4..). With increasing principal energy levels, the electron gets farther from the nucleus. The angular momentum number (l) describes the shape of the orbital (s,p,d,f). The magnetic quantum number (ml) shows th...
by sbeall_1C
Thu Oct 17, 2019 6:17 pm
Forum: *Shrodinger Equation
Topic: Negative sign in Equation
Replies: 4
Views: 64

Negative sign in Equation

In class and the workshops, we looked at a diagram where the Y-axis is Energy, and the values are all negative building up to E=0 when the energy level goes toward infinity. Can someone explain why the energy values are negative? Is it due to the equation?
by sbeall_1C
Thu Oct 17, 2019 4:42 pm
Forum: Properties of Light
Topic: 1A7b textbook solution typo?
Replies: 5
Views: 85

Re: 1A7b textbook solution typo?

Dr. Lavelle has a page on his website that lists all the errors in the Solutions Manual! You can check there if you are questioning an answer as well!
by sbeall_1C
Thu Oct 17, 2019 4:35 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 7
Views: 116

Re: Nodal Planes

Hey! Is there any connection between the location of the nucleus and the nodal plane? Is the nucleus located on the nodal plane, since you cannot find an electron in the nucleus or the nodal plane?
by sbeall_1C
Sat Oct 12, 2019 6:28 pm
Forum: DeBroglie Equation
Topic: Mass of Protons, Neutrons, Electrons, Etc.
Replies: 3
Views: 28

Re: Mass of Protons, Neutrons, Electrons, Etc.

The value for the mass of the subatomic particles are given in the book and on the tests, the masses should be on the information sheet.
by sbeall_1C
Sat Oct 12, 2019 6:27 pm
Forum: DeBroglie Equation
Topic: Circular standing waves
Replies: 4
Views: 51

Re: Circular standing waves

I believe that the circular standing wave model represents how the electrons have quantized energy states in atoms. The electrons orbit the nucleus in waves in discrete distances from the nucleus. We cannot know exactly the position of the electron but it is orbiting somewhere in the realm of the ci...

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