## Search found 75 matches

Sun Mar 17, 2019 10:35 am
Forum: Second Order Reactions
Topic: units of K
Replies: 3
Views: 352

### Re: units of K

The units for k in a second order reaction is M^-1s^-1
Sun Mar 17, 2019 10:18 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 16
Views: 601

### Re: Catalysts

Catalysts lower the curve of the reaction.
Sun Mar 17, 2019 10:16 am
Forum: Zero Order Reactions
Topic: overall rate
Replies: 5
Views: 432

### Re: overall rate

You're correct. You don't add the zero order.
Sun Mar 10, 2019 8:30 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Order
Replies: 2
Views: 140

### Re: Order

^I agree. When solving for one experiment, you determine the numbers you are doing the calculations with by seeing which other variables are constant. So for example, if you are trying to find the rate of A, you look at the chart to see when B and C are constant in an experiment and then divide thos...
Sun Mar 10, 2019 8:26 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Activation Energy
Replies: 3
Views: 122

### Re: Activation Energy

Increasing activation energy means that the reaction rate is increasing because you are making the reaction slower and causes more energy to be needed.
Sat Mar 09, 2019 11:37 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Fast Step vs Slow Step
Replies: 3
Views: 125

### Fast Step vs Slow Step

What's the main difference between fast and slow steps and how can you tell them apart if they aren't mentioned? Also, why is the slow step the one that determines the reaction?
Sun Mar 03, 2019 3:35 pm
Forum: Zero Order Reactions
Topic: Units of k in Zero Order Reactions
Replies: 4
Views: 164

### Units of k in Zero Order Reactions

Are the units for zero order reactions M/s or mol/(L*s)?
Sun Mar 03, 2019 3:31 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Value of “k” in Kinetics
Replies: 5
Views: 451

### Re: Value of “k” in Kinetics

k is products over reactants, so if k > 1, then the products are favored and the forward rate is faster; however, if k < 1, then the reactants are favored and the reverse rate is faster.
Sun Mar 03, 2019 3:29 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Stoichiometric coefficients
Replies: 4
Views: 574

### Re: Stoichiometric coefficients

Yes, they are used for elementary step rate laws, but always keep in mind you cannot use it when you're trying to solve for the rate law of the overall reaction because the coefficients may not always line up.
Sun Mar 03, 2019 3:25 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Purpose of Kinetics
Replies: 6
Views: 393

### Re: Purpose of Kinetics

The purpose of kinetics is to see what various substances affects the rate of the reaction and how fast the reactants are turned into products. So basically what you pretty much got it.
Sun Mar 03, 2019 3:22 pm
Forum: First Order Reactions
Topic: Negative Orders
Replies: 5
Views: 421

### Re: Negative Orders

Yes, negative orders are possible and just means that whatever the substance is, it decreases and cases the reaction rate to increase. I had the same confusion, but a TA told me to get familiar with negative orders and fractions.
Fri Feb 22, 2019 9:30 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 5
Views: 176

### Re: salt bridge

Ultimately, a salt bridge is what helps maintain a battery and allows it to work. When adding a salt bridge, it the elements K+ favors the cathode and CL- favors the anion, and helps the stabilize the flow of electrons between the two.
Fri Feb 22, 2019 9:24 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Finding K or Q with Nernst's Equation
Replies: 2
Views: 199

### Finding K or Q with Nernst's Equation

If a problem were to ask you to find the value of K or Q, how would you do this when using Nernst's equation?
Fri Feb 22, 2019 9:23 am
Forum: Balancing Redox Reactions
Topic: Redox and Oxidation
Replies: 3
Views: 170

### Re: Redox and Oxidation

First, you should always see if the equation is balanced out or not. From there, you go to each compound/ion and find the charge of each one. From there, you compare the reactants with the products to see which are being reduced and which are being oxidized. The reducing agent is the one that gets o...
Tue Feb 12, 2019 10:56 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isothermal vs. Non-Isothermal
Replies: 1
Views: 126

### Isothermal vs. Non-Isothermal

Just for clarification, why do isothermal systems use the constant R and why don't non-isothermal systems use R?
Tue Feb 12, 2019 10:54 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Higher Molar Entropy
Replies: 3
Views: 182

### Re: Higher Molar Entropy

Molecules that are more complex (larger in size) are the ones with higher entropy. Also, residual entropy is the difference in entropy (left over in the system) when it is at absolute 0 Kelvin.
Tue Feb 12, 2019 10:51 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Standard Molar Entropies
Replies: 2
Views: 130

### Re: Standard Molar Entropies

Larger compounds/atoms are more complex and larger in weight, allowing it to have accessible vibrational energy levels. This is what causes it to have higher entropy.
Fri Feb 08, 2019 8:00 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Standard Molar Entropy
Replies: 1
Views: 111

### Standard Molar Entropy

Why aren't there any delta symbols for the standard molar entropy formula? Also, why are the components always positive?
Fri Feb 08, 2019 7:58 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Relationship Between Temperature and Entropy
Replies: 1
Views: 81

### Relationship Between Temperature and Entropy

Just to be clear, does low temperature mean there's an increase in entropy? Or is it the opposite?
Fri Feb 08, 2019 7:54 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Steam vs. Boiled Water
Replies: 2
Views: 124

### Steam vs. Boiled Water

Why is steam hotter than boiled water? It was discussed in lecture, but I still am confused with the concept.
Sun Feb 03, 2019 9:30 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Replies: 4
Views: 175

Adiabatic means q=0, which means delta U=w
Sun Feb 03, 2019 9:29 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Isochoric
Replies: 4
Views: 178

### Re: Isochoric

Isochoric means delta V=0, which means w=0 and delta U=q
Sun Feb 03, 2019 9:28 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Isobaric
Replies: 2
Views: 112

### Re: Isobaric

Isobaric means that delta P=0 or qp=delta H, which means that delta U=delta H—P*delta V
Sun Feb 03, 2019 9:23 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Negative or Positive Work
Replies: 3
Views: 131

### Negative or Positive Work

When do you know when work is negative or positive?
Sun Feb 03, 2019 9:20 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat (Csp)
Replies: 3
Views: 226

### Specific Heat (Csp)

On an exam, when conducting a problem using the equation, q=g*Csp*deltaT, are we supposed to memorize the specific heat (Csp) even if the problem doesn't give it to you, or will it be given?
Sun Feb 03, 2019 9:09 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated System Example
Replies: 4
Views: 182

### Isolated System Example

I understand the concepts of systems, but what's a good example of an isolated system?
Thu Jan 24, 2019 1:05 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: q vs. qp
Replies: 2
Views: 52

### q vs. qp

What is the difference between q and qp?
Thu Jan 24, 2019 1:04 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Heat and Work Not State Properties
Replies: 1
Views: 53

### Heat and Work Not State Properties

Why aren't heat and work considered a state property?
Thu Jan 24, 2019 1:03 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: p in qp
Replies: 1
Views: 35

### p in qp

What does the p represent in the expression "qp"?
Mon Jan 14, 2019 11:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE table
Replies: 3
Views: 146

### ICE table

When conducting the ICE table, are aqueous and gas compounds allowed only?
Mon Jan 14, 2019 11:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs. K
Replies: 5
Views: 231

### Q vs. K

What's the difference between Q and K??
Mon Jan 14, 2019 11:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Change in temperature and K
Replies: 2
Views: 117

### Change in temperature and K

Why does a change in temperature affect K and not a change in pressure or concentration?
Mon Jan 07, 2019 11:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressure Problems
Replies: 1
Views: 97

### Partial Pressure Problems

When working on problems dealing with partial pressure, should we always write a "P" before the constant? (e.g. Kp= PCO2) Because it was shown to do it in lecture?
Mon Jan 07, 2019 11:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Large/Small Equilibrium Constant
Replies: 2
Views: 77

### Large/Small Equilibrium Constant

In lecture we went over how if there is a large equilibrium constant, it is a result from it having less product because it is stable; however, if the product is more than the reaction, will it make it a smaller equilibrium constant? And would it count as a reverse reaction?
Mon Jan 07, 2019 11:13 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Concentration vs Pressure
Replies: 6
Views: 184

### Re: Equilibrium Concentration vs Pressure

It depends on the information given in the problem. It will most likely ask for you to find either or.
Mon Jan 07, 2019 11:10 pm
Forum: Ideal Gases
Topic: R in PV=nRT
Replies: 34
Views: 689

### R in PV=nRT

What does the R represent in the equation PV=nRT? and what are the units?
Wed Dec 05, 2018 5:08 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: HF ion
Replies: 3
Views: 326

### HF ion

Why is HF not considered a strong acid??
Wed Dec 05, 2018 5:02 pm
Forum: Conjugate Acids & Bases
Topic: Strong acids/bases and Weak conjugate acids/bases
Replies: 1
Views: 63

### Strong acids/bases and Weak conjugate acids/bases

Just to be clear, strong acids usually have weak conjugate bases and strong bases usually have weak conjugate acids right?
Wed Dec 05, 2018 4:59 pm
Forum: Lewis Acids & Bases
Topic: Resonance Structures and Acids/Bases
Replies: 1
Views: 45

### Resonance Structures and Acids/Bases

If a compound consists of resonance structures, can that help distinguish if it's a weak or strong acid or base?
Wed Dec 05, 2018 4:56 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pOH from pH
Replies: 2
Views: 153

### Re: pOH from pH

Yup! When given pH and want to find pOH, you simply subtract the pH by 14, due to the fact that pH and pOH together equal 14.
Wed Dec 05, 2018 4:53 pm
Forum: Conjugate Acids & Bases
Topic: OH- vs -OH
Replies: 3
Views: 176

### OH- vs -OH

I noticed in lecture, Professor Lavelle wrote hydroxide ion as [-OH], instead of [OH-]. BY moving the charge, does it alter the compound? Are they both the same or are they different?
Wed Dec 05, 2018 4:50 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 11221

### Re: FINAL PRACTICE - Lyndon's Churro Review Session[ENDORSED]

THANK YOU!!!!
Sun Dec 02, 2018 10:07 am
Forum: Naming
Topic: Oxidation State
Replies: 4
Views: 150

### Re: Oxidation State

You first find the oxidative number of the compound (given) and are usually given another oxidative number of one of the atoms or you must know (e.g. (NH3) is 0). From there, you find the difference between the oxidative states to find the oxidative number of the missing one(s).
Sun Dec 02, 2018 10:00 am
Forum: Conjugate Acids & Bases
Topic: Strong and Weak Acids and Bases in Relations with H2O
Replies: 3
Views: 126

### Strong and Weak Acids and Bases in Relations with H2O

What are the relationships between strong and weak acids and bases with water? Do they dissociate or not? Does one dissociate faster than the other?
Sun Dec 02, 2018 9:51 am
Forum: Bronsted Acids & Bases
Topic: Bronsted and Lewis Acids/Bases
Replies: 1
Views: 113

### Bronsted and Lewis Acids/Bases

Do the definitions of Bronsted acids and bases and Lewis acids and bases relate to oxidation and reduction reactions? Just thought I saw a connection with a bio topic and chem topic.
Sat Nov 24, 2018 10:13 am
Forum: Determining Molecular Shape (VSEPR)
Topic: vsepr shape
Replies: 6
Views: 280

### Re: vsepr shape

Here's a website that can also help.

http://chemed.chem.purdue.edu/genchem/t ... vsepr.html
Sat Nov 24, 2018 10:12 am
Forum: Determining Molecular Shape (VSEPR)
Topic: vsepr shape
Replies: 6
Views: 280

### Re: vsepr shape

The two models are pretty similar, but I first start by drawing out the lewis structure in the most linear shape as possible. Then I add the dotted and darkened lines as much needed. I also circle in the lone pairs. From there, I find it easier to the the VSEPR shape. Hope this helps.
Sat Nov 24, 2018 10:01 am
Forum: Electronegativity
Topic: Largest Electronegativity
Replies: 4
Views: 177

### Re: Largest Electronegativity

Fluorine is the element with the highest electronegativity
Sat Nov 24, 2018 9:57 am
Forum: Resonance Structures
Topic: Resonance in VSEPR Theory
Replies: 1
Views: 265

### Resonance in VSEPR Theory

Do resonance structures also occur in VSEPR models? Like when you are drawing them with the dotted lines?
Sat Nov 24, 2018 9:55 am
Forum: Sigma & Pi Bonds
Topic: Delta Bonds
Replies: 4
Views: 177

### Re: Delta Bonds

When all four lobes of the d orbitals interact with each other making it a covalent bond.
Sat Nov 24, 2018 9:53 am
Forum: Sigma & Pi Bonds
Topic: Amount of sigma bonds
Replies: 6
Views: 519

### Re: Amount of sigma bonds

Single bond = one sigma bond, double bond = one sigma bond and one pi bond, and triple = one sigma bond and two pi bonds
Sat Nov 24, 2018 9:49 am
Forum: Sigma & Pi Bonds
Topic: Sigma and Pi Bonds
Replies: 2
Views: 100

### Sigma and Pi Bonds

Is there a difference in length/distance for sigma and pi bonds?
Sat Nov 24, 2018 9:42 am
Forum: Hybridization
Topic: Writing out Hybridization
Replies: 8
Views: 259

### Writing out Hybridization

If a d-block does appear, would writing the hybridization out like sp^3d be correct or do we have to put the d in the beginning first like dsp^3?
Sat Nov 24, 2018 9:34 am
Forum: Lewis Structures
Topic: Lewis Structure to 3D
Replies: 3
Views: 216

### Re: Lewis Structure to 3D

I don't believe so, but it's always good to know how to draw the 3D model
Sat Nov 24, 2018 9:32 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape
Replies: 5
Views: 151

### Re: Molecular Shape

I think you have to memorize those as well. Or you can look at the shape and determine it from there, but you would have to draw the shape correctly if you are looking doing it that way
Tue Nov 06, 2018 10:25 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizing Power vs Polarisabiltiy
Replies: 2
Views: 123

### Polarizing Power vs Polarisabiltiy

What's the difference between polarizing power and polarisability?
Sun Nov 04, 2018 9:55 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 3
Views: 197

### Resonance Structures

Are we supposed to draw all of the resonance structures even if the problem does not ask?
Sun Nov 04, 2018 9:52 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge and Lewis Structures
Replies: 5
Views: 261

### Formal Charge and Lewis Structures

When drawing out the Lewis Structures, are we supposed to add the charges on the atoms even when it's not asked in the problem?
Sun Nov 04, 2018 9:48 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 5
Views: 199

### Electronegativity

I understand the trend of electronegativity, but what is the purpose of electronegativity?
Fri Oct 26, 2018 10:06 pm
Forum: Lewis Structures
Topic: Periodic Table Trends
Replies: 3
Views: 134

### Re: Periodic Table Trends

There shouldn't be any exceptions in regards to periodic trends and drawing Lewis structures
Fri Oct 26, 2018 10:03 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures with Charges
Replies: 6
Views: 376

### Drawing Lewis Structures with Charges

When drawing Lewis Structures for polyatomic molecules, what are the rules if charges exist?
Fri Oct 26, 2018 10:02 pm
Forum: Octet Exceptions
Topic: Octet Exceptions
Replies: 3
Views: 235

### Octet Exceptions

Why are H, He, Li, and Be exceptions to the octet rule?
Thu Oct 18, 2018 11:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: How to Find the Number of Orbitals
Replies: 3
Views: 131

### How to Find the Number of Orbitals

We haven't mentioned in Lecture 1 yet, but how do you find the number orbital of in a sub shell??
Thu Oct 18, 2018 11:33 pm
Forum: Einstein Equation
Topic: Values of Each Symbol
Replies: 3
Views: 179

### Values of Each Symbol

Will the values of the symbols be given on the exam or should we just memorize them? (e.g. Planck's constant or speed of light)
Fri Oct 12, 2018 3:04 pm
Forum: DeBroglie Equation
Topic: Week 3 Textbook Assignment
Replies: 2
Views: 71

### Week 3 Textbook Assignment

For week 3, are we choosing another set of 7 questions from the Quantum World chapter or do we move on to the Chemical Bonds chapter?
Fri Oct 12, 2018 9:28 am
Forum: Einstein Equation
Topic: Symbol for frequency
Replies: 12
Views: 781

### Re: Symbol for frequency

I would just stick with v because that's what Lavelle has been giving us.
Thu Oct 11, 2018 4:04 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: En=-hR/n^2
Replies: 3
Views: 70

### En=-hR/n^2

Why is this equation negative again? I know Professor Lavelle mentioned this in class, but can someone please refresh it to me?
Mon Oct 08, 2018 9:36 pm
Forum: Photoelectric Effect
Topic: Significance of Photoelectric Effect
Replies: 3
Views: 118

### Significance of Photoelectric Effect

Can someone please narrow down the significance of photoelectric effect? I still don't get it.
Mon Oct 08, 2018 9:34 pm
Forum: Einstein Equation
Topic: Einstein's Equation: E=hv
Replies: 11
Views: 619

### Einstein's Equation: E=hv

What does the h in E=hv represent again??
Wed Oct 03, 2018 7:39 pm
Forum: SI Units, Unit Conversions
Topic: Textbook Homework Assignment
Replies: 11
Views: 800

### Re: Textbook Homework Assignment

Quick Question: Are we supposed to write down the questions for the textbook problems when doing the homework??
Tue Oct 02, 2018 12:30 pm
Forum: SI Units, Unit Conversions
Topic: Textbook Homework Assignment
Replies: 11
Views: 800

### Re: Textbook Homework Assignment

You complete any 7 problems that you want to do
Mon Oct 01, 2018 6:46 pm
Forum: SI Units, Unit Conversions
Topic: Textbook Homework Assignment
Replies: 11
Views: 800

### Re: Textbook Homework Assignment

False alarm. I figured it out (:
Mon Oct 01, 2018 6:12 pm
Forum: Balancing Chemical Reactions
Topic: States of Atoms
Replies: 7
Views: 166

### States of Atoms

If I don't know the states of atoms when writing a chemical equation, what should I do? Leave it blank or just do an educated guess?
Mon Oct 01, 2018 6:08 pm
Forum: Balancing Chemical Reactions
Topic: Law of Conservation of Mass [ENDORSED]
Replies: 7
Views: 303

### Law of Conservation of Mass[ENDORSED]

Anyone willing to give a simpler definition of the Law of Conservation of Mass?
Mon Oct 01, 2018 6:02 pm
Forum: SI Units, Unit Conversions
Topic: Textbook Homework Assignment
Replies: 11
Views: 800

### Textbook Homework Assignment

Hey guys. Am I the only one that is confused about where the problems are located in the textbook? What pages are the textbooks problems in, for the 6th and 7th edition??