## Search found 66 matches

Sun Mar 17, 2019 1:11 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: K vs k1/k'1
Replies: 6
Views: 469

### Re: K vs k1/k'1

I believe that it will tell you which way to write it but otherwise either way should be fine.
Sun Mar 17, 2019 1:08 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cell concentration
Replies: 2
Views: 259

### Re: cell concentration

Concentration cells have the same elements on both side but with different concentrations. The difference in concentrations allows the reaction to occur.
Sun Mar 17, 2019 1:05 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 4
Views: 352

### Re: salt bridge

A salt bridge allows ions to go into solutions and it prevents the build-up of charges.
Wed Mar 06, 2019 11:38 pm
Forum: General Rate Laws
Topic: Which law?
Replies: 2
Views: 134

### Re: Which law?

We will most likely have to determine the order of the reaction, but we will be given the necessary information to determine this.
Wed Mar 06, 2019 11:33 pm
Forum: First Order Reactions
Topic: 1/2 life
Replies: 7
Views: 279

### Re: 1/2 life

Raj_Bains_2C wrote:The half-life for first order dow not depend on the initial concentration.

*does not*
Wed Mar 06, 2019 11:33 pm
Forum: First Order Reactions
Topic: 1/2 life
Replies: 7
Views: 279

### Re: 1/2 life

The half-life for first order dow not depend on the initial concentration.
Wed Mar 06, 2019 11:31 pm
Forum: Van't Hoff Equation
Topic: Temp Units
Replies: 11
Views: 531

### Re: Temp Units

You would use Kelvin (K).
Wed Mar 06, 2019 11:30 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Intermediates
Replies: 4
Views: 159

### Re: Reaction Intermediates

The reaction intermediate does not appear in the reactants or products of the overall reaction. It only appears in the intermediate steps.
Wed Mar 06, 2019 11:28 pm
Forum: General Rate Laws
Topic: Slope
Replies: 2
Views: 119

### Re: Slope

For first order, the straight line plot is ln[A] vs time. For second order, the straight line plot is 1/[A] vs time. For zero order, the straight line plot is [A] vs time.
Wed Mar 06, 2019 11:24 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6th edition 14.43
Replies: 1
Views: 63

### Re: 6th edition 14.43

Q is just relating the products to the reactants when it is not at equilibrium, so you can use concentration of partial pressures to relate them.
Wed Mar 06, 2019 11:22 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: how is kinetics different?
Replies: 17
Views: 682

### Re: how is kinetics different?

Thermodynamics only cares about the initial and final states, while kinetics focuses on the pathway of the reaction.
Wed Mar 06, 2019 11:21 pm
Forum: General Rate Laws
Topic: Deriving Rate Laws
Replies: 3
Views: 155

### Re: Deriving Rate Laws

I don't think that we will have to derive the actual rate laws, but I think that knowing how to do it will be helpful in answering some questions.
Wed Mar 06, 2019 11:20 pm
Forum: First Order Reactions
Topic: Exponential Curve
Replies: 6
Views: 211

### Re: Exponential Curve

This is because the reactant concentration decreases exponentially in a first order reaction.
Fri Feb 22, 2019 10:07 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 7
Views: 312

### Re: Test 2

Test 2 will cover everything we have learned in weeks 6 and 7.
Fri Feb 22, 2019 10:04 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Calculating E naught of the cell
Replies: 3
Views: 157

### Re: Calculating E naught of the cell

There is only one way to calculate E that we have learned so far. The method involving the half reactions is a more descriptive way of the method using just the equation.
Fri Feb 22, 2019 9:56 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cathode vs. Anode
Replies: 9
Views: 292

### Re: Cathode vs. Anode

The cathode is the reduction side and the anode is the oxidation side.
Thu Feb 14, 2019 10:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp equilibrium constant
Replies: 6
Views: 333

### Re: Kp equilibrium constant

I think that atm and bar are the two units that can be used to calculate Kp values.
Thu Feb 14, 2019 10:52 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Replies: 8
Views: 294

This is because entropy is a state function, so the path taken does not matter. Just the final and initial values matter.
Thu Feb 14, 2019 10:51 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Change Diagram of Water
Replies: 6
Views: 252

### Re: Phase Change Diagram of Water

Steam at 100 C contains more heat than water at 100 C because heat goes into breaking intermolecular bonds.
Sat Feb 09, 2019 9:11 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Open vs Closed System
Replies: 13
Views: 1004

### Re: Open vs Closed System

In an open system, the container is left open, so matter (like gasses) and energy (like heat) can escape the system, which is the container. In a closed system, the container has been closed (a cap is placed on a jar, for example), so matter (like gasses) can't escape, but energy (like heat) can sti...
Sat Feb 09, 2019 9:06 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: q= -w
Replies: 8
Views: 226

### Re: q= -w

This means that in isothermal systems, the heat lost is equal to the work done, but a negative sign is added.
Sat Feb 09, 2019 9:03 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: U
Replies: 7
Views: 196

### Re: U

U is a state property because the path taken does not matter. Only the initial and final conditions matter.
Fri Feb 01, 2019 4:23 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Finding Heat
Replies: 4
Views: 149

### Re: Finding Heat

You can use both Kelvin and Celsius because you just need the change in temperature.
Fri Feb 01, 2019 4:20 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated Systems
Replies: 6
Views: 214

### Re: Isolated Systems

I don't think that there is any way to prove 100% isolation of any system except for the universe. Even an insulated water bottle or thermos has a very small amount of heat lost, so it is not completely 100% isolated. But, as Lavelle explained in lecture, that heat lost is extremely small compared t...
Fri Feb 01, 2019 4:17 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: 1st law of thermodynamics
Replies: 7
Views: 248

### Re: 1st law of thermodynamics

When energy goes into the surroundings in an experiment, it is not lost. It is just going into the universe. The fact that the universe is an isolated system means that it does not lose energy, so energy is conserved overall. The total energy in the universe never changes.
Wed Jan 23, 2019 5:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE boxes
Replies: 5
Views: 181

### Re: ICE boxes

Yes. You can use an ICE chart for both partial pressures and concentrations.
Wed Jan 23, 2019 5:13 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 5
Views: 110

### Re: Hess's Law

We did not go over Hess's Law in 14A and I believe that it will be covered later in the quarter in the thermodynamics outline.
Wed Jan 23, 2019 5:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Table Clarification
Replies: 4
Views: 123

### Re: ICE Table Clarification

We are allowed to assume this when K is less than 10^-3.
Thu Jan 17, 2019 12:14 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Tricks for ICE tables
Replies: 5
Views: 191

### Re: Tricks for ICE tables

Most of the time you would use ICE tables when solving a problem with weak acids and bases.
Thu Jan 17, 2019 12:12 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 11
Views: 924

### Re: Le Chatelier's Principle

Decreasing the pressure of one side makes it go toward that side. Increasing the pressure of one side makes it go toward the other side.
Wed Jan 16, 2019 11:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE
Replies: 5
Views: 196

### Re: ICE

The x is just a variable that represents the change in concentration, which we are trying to solve for.
Fri Jan 11, 2019 4:18 pm
Forum: Ideal Gases
Topic: What does K represent?
Replies: 9
Views: 327

### Re: What does K represent?

K is the ratio of the concentrations or partial pressures of the products to reactants at equilibrium. It is a way to tell is a reaction is at equilibrium and it helps us know what needs to happen to take the reaction to equilibrium.
Fri Jan 11, 2019 4:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp
Replies: 9
Views: 296

### Re: Kp

We sometimes use KP instead of KC for gases because that is what the problem gives us as the initial information.
Fri Jan 11, 2019 4:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q and K
Replies: 13
Views: 299

### Re: Q and K

K is when the reaction is at equilibrium and Q is the current state of the reaction. If Q = K, the reaction is at equilibrium and if Q does not equal K, the reaction is not at equilibrium.
Wed Dec 05, 2018 4:31 pm
Forum: Naming
Topic: Poly v Mono
Replies: 2
Views: 43

### Re: Poly v Mono

A mono-dentate only has one ligand attached to the transition metal, while a poly-dentate has more than one ligand attached to the transit metal. This does affect the naming of the compound.
Wed Dec 05, 2018 4:28 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calc pH
Replies: 1
Views: 106

### Re: Calc pH

We do not need to calculate the pH of a weak acid solution unless it explicitly gives us the H3O+ concentration.
Wed Dec 05, 2018 4:25 pm
Forum: Hybridization
Topic: Identifying Hybridization
Replies: 2
Views: 150

### Re: Identifying Hybridization

If the whole molecule has no charge, then it is safe to assume that the two lone pairs do still exist. Therefore, the hybridization is sp3.
Wed Dec 05, 2018 3:48 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: electron transitions
Replies: 2
Views: 413

### Re: electron transitions

Yes, this is correct. When an electron drops in energy levels, it gives off energy, so the change in energy is negative.
Wed Dec 05, 2018 3:47 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Number
Replies: 7
Views: 258

### Re: Coordination Number

The oxidation number is the overall charge on the complex, while the coordination number is the number of ligands bonded to the central tradition metal.
Wed Dec 05, 2018 3:43 pm
Forum: Lewis Structures
Topic: H2SeO4 Structure
Replies: 1
Views: 152

### Re: H2SeO4 Structure

I am not sure what the reason is for this, but I just know that the whole lewis structure is more stable if the H is attached to the O instead of the Se. I thing that most structures like to have the OH groups instead of the H being attached to the central atom.
Fri Nov 30, 2018 4:42 pm
Forum: Sigma & Pi Bonds
Topic: Triple bond?
Replies: 18
Views: 768

### Re: Triple bond?

One triple bond should contain one sigma bond and two pi bonds.
Fri Nov 30, 2018 4:41 pm
Forum: Dipole Moments
Topic: Molecular Geometry and polarity
Replies: 5
Views: 157

### Re: Molecular Geometry and polarity

It will only be non polar if the two outside atoms are identical.
Fri Nov 30, 2018 4:31 pm
Forum: Hybridization
Topic: 7th Edition 2.45
Replies: 1
Views: 95

### Re: 7th Edition 2.45

1. It is referring to the sigma/pi bonds, but I believe it also wants you to indicate which orbitals are bonding to each other. 2. All three sp^2 hybrid orbitals are identical so you don't have to indicate which one is used. 3. The hybridization of the lone pairs just refers to which hybrid orbitals...
Tue Nov 20, 2018 10:51 pm
Forum: Lewis Structures
Topic: Lewis structure for POCl3
Replies: 7
Views: 476

### Re: Lewis structure for POCl3

P is in the center because it has the lowest ionization energy out of the atoms in the structure.
Tue Nov 20, 2018 10:48 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: higher polarizability
Replies: 4
Views: 180

### Re: higher polarizability

The bonding electrons of the smaller atom would be closer to the nucleus so they would be more attracted to the positive charge from the protons.
Tue Nov 20, 2018 10:45 pm
Forum: Electronegativity
Topic: polarizability of cations
Replies: 2
Views: 85

### Re: polarizability of cations

In high school I learned that greater charges always matter more than a smaller size.
Mon Nov 12, 2018 9:14 pm
Forum: Bond Lengths & Energies
Topic: bond length such as the midterm question
Replies: 5
Views: 210

### Re: bond length such as the midterm question

I believe that a specific value is preferred but a range should be accepted as a correct answer.
Mon Nov 12, 2018 9:05 pm
Forum: Ionic & Covalent Bonds
Topic: Noncovalent Interactions
Replies: 4
Views: 137

### Re: Noncovalent Interactions

This seems correct based on what we have learned so far. As there are more non covalent interactions between molecules, the intermolecular bonds become stronger, causing more stability and higher boiling points.
Mon Nov 12, 2018 9:02 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 3
Replies: 8
Views: 1346

### Re: Test 3

I believe that test 3 will only cover the material from after the midterm to right before the test. It should not cover everything from the beginning of the quarter.
Sat Nov 03, 2018 9:59 pm
Forum: Lewis Structures
Replies: 4
Views: 106

Questions on radicals may be on the midterm so it is best to study this topic.
Sat Nov 03, 2018 9:54 pm
Forum: Lewis Structures
Topic: lewis acid/base
Replies: 3
Views: 111

### Re: lewis acid/base

I do not know the answer to this but I am just letting you know that we have not covered this in lecture yet and it will not be on the midterm.
Sat Nov 03, 2018 9:47 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Exam 2 Question 1A
Replies: 2
Views: 181

### Re: Exam 2 Question 1A

The only thing you did wrong in this question was that you didn't double the resulting mass of one oxygen atom. Oxygen exists is a diatomic state, so the formula for the oxygen molecule is actually O2.
Sat Oct 27, 2018 8:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 11
Views: 384

### Re: Midterm

The midterm is going to cover everything we have covered from the beginning of the quarter.
Sat Oct 27, 2018 8:16 pm
Forum: Ionic & Covalent Bonds
Topic: Electron Affinity vs. Ionization Energy [ENDORSED]
Replies: 4
Views: 142

### Re: Electron Affinity vs. Ionization Energy[ENDORSED]

Electron affinity is how much an element attracts another electron, so it is directly related to ionization. If an element has a very high or very low electron affinity, it will easily gain or loose an electron, so it will easily ionize.
Sat Oct 27, 2018 8:11 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Spin Number
Replies: 5
Views: 197

### Re: Magnetic Spin Number

Parallel electrons do exist in the same orbital but they are in different sub-orbitals, as indicated by the m in the n, l, m quantum numbers.
Wed Oct 17, 2018 6:15 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital Notations
Replies: 3
Views: 87

### Re: Orbital Notations

I believe they are squared because they are overlapping the p-orbitals, but I am not sure that this is the reason.
Wed Oct 17, 2018 6:10 pm
Forum: General Science Questions
Topic: Midterm
Replies: 6
Views: 375

### Re: Midterm

The midterm time is 6-8 pm and I think that the midterm location will be revealed at a later date.
Wed Oct 17, 2018 6:03 pm
Forum: *Shrodinger Equation
Topic: Orbital Planes
Replies: 2
Views: 96

### Re: Orbital Planes

Raj_Bains_3C wrote:I believe that they do always stay in the dame formation, but as Dr, Lavelle said, do not pay too much attention to the shapes because they are only mathematical models.

*same formation, not "dame"
Wed Oct 17, 2018 6:02 pm
Forum: *Shrodinger Equation
Topic: Orbital Planes
Replies: 2
Views: 96

### Re: Orbital Planes

I believe that they do always stay in the dame formation, but as Dr, Lavelle said, do not pay too much attention to the shapes because they are only mathematical models.
Wed Oct 17, 2018 5:54 pm
Forum: Properties of Light
Topic: Threshold Energies
Replies: 5
Views: 146

### Re: Threshold Energies

Different metals have different threshold energies because they have a different number of protons, electrons, and energy levels. If the metal has many protons and electrons, there will be more energy levels, resulting in the electrons being further away from the nucleus. These negatively charged e...
Fri Oct 12, 2018 12:56 am
Forum: Properties of Light
Topic: Threshold Energies
Replies: 5
Views: 146

### Re: Threshold Energies

Different metals have different threshold energies because they have a different number of protons, electrons, and energy levels. If the metal has many protons and electrons, there will be more energy levels, resulting in the electrons being further away from the nucleus. These negatively charged el...
Fri Oct 12, 2018 12:42 am
Forum: Properties of Light
Topic: speed of light
Replies: 8
Views: 332

### Re: speed of light

I don't think that it matters on the homework problems if we use 3.0 x 10^8 m/s or a more precise value, but for the tests, I would stick to using the value that is on the constants and equations sheet.
Fri Oct 12, 2018 12:39 am
Forum: SI Units, Unit Conversions
Topic: Homework for Week 2
Replies: 16
Views: 497

### Re: Homework for Week 2

My TA told me that we were allowed to do any homework problems from previous assignments, so we can turn in some week 1 problems for the week 3 homework. As far as I understand it, we can just do any problems that we feel like we need more practice on.
Fri Oct 05, 2018 5:58 pm
Forum: Balancing Chemical Reactions
Topic: States of Matter
Replies: 11
Views: 426

### Re: States of Matter

The states of matter should be stated most of the time, but as far as I know it does not affect any calculations made using the balanced chemical equation. I do think that they are just there for analytical purposes and to just show what states of matter the reactants and products are in.
Fri Oct 05, 2018 5:55 pm
Forum: Significant Figures
Topic: Determining Sig Figs
Replies: 6
Views: 220

### Re: Determining Sig Figs

It is best to obey the rules of significant figures all the time to retain the accuracy of measurements. It might help you to review the basic rules of significant figures.
Examples: 5.48 x 6.2 = 34 8.2 x 0.6 = 5 9.01 x 2.333 = 21.0
Fri Oct 05, 2018 5:49 pm
Forum: Molarity, Solutions, Dilutions
Topic: Part C of question E.17
Replies: 2
Views: 62

### Re: Part C of question E.17

You did not need to do any calculations for this problem because it already states that there are equal amounts of atoms. Therefore, none from the pair contains more moles of atoms. They contain equal amounts.