Search found 65 matches
- Wed Mar 13, 2019 1:07 am
- Forum: General Rate Laws
- Topic: writing rate law
- Replies: 2
- Views: 326
Re: writing rate law
I believe it is because the rate law is in terms of the products so reactants are the ones affecting the production rate
- Wed Mar 13, 2019 1:04 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Test 2 #6 part c
- Replies: 1
- Views: 331
Test 2 #6 part c
Did anyone get #6 part c right and if you did could you give me the answer and how you got it because I got a and b right but c wrong and I'm not sure what I did wrong
- Wed Mar 13, 2019 12:54 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius Equation
- Replies: 2
- Views: 311
Re: Arrhenius Equation
Are the k reaction rates swithced too? Because if k is switched too then it is fine
- Fri Mar 08, 2019 12:44 pm
- Forum: Zero Order Reactions
- Topic: Differentiating Zero and One Order Reactions
- Replies: 2
- Views: 398
Re: Differentiating Zero and One Order Reactions
The 1st order reaction should look like an exponential decay function
- Tue Mar 05, 2019 5:34 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Homework 15.17 6th Edition
- Replies: 1
- Views: 294
Re: Homework 15.17 6th Edition
check to see the order for the reactant C. If reactant C iz zero order, than it doesn't matter what concentration C is because it has no effect on the rate
- Tue Mar 05, 2019 11:59 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 6N.15
- Replies: 1
- Views: 445
6N.15
Calculate the potential of a cell constructed with two nickel electrodes. The electrolyte in one compartment is 1.0 M Ni(NO3)2. In the other compartment, NaOH has been added to a Ni(NO3)2 solution until the pH = 11 at 298 K. Use Table 6I.1 I got the [OH-} concentration but I'm not really sure how to...
- Mon Feb 25, 2019 4:40 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Homework question
- Replies: 3
- Views: 389
Re: Homework question
in this equation n = the number of moles of electrons being transferred
- Mon Feb 25, 2019 4:40 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6M5 part a
- Replies: 2
- Views: 438
6M5 part a
For the cell diagram the answer doesn't include a platinum(s) on the anode side when there is no solid. It only has Hg(l) and Hg2 2+(aq). I thought we had to always include Pt(s) when there's no solid so why does the answer not include it on this side?
- Mon Feb 25, 2019 4:30 pm
- Forum: Student Social/Study Group
- Topic: Topic 6N
- Replies: 1
- Views: 1579
Topic 6N
For the people with 7th edition textbooks will anything in topic 6N be in test 2?
- Wed Feb 20, 2019 12:25 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 4J.15
- Replies: 2
- Views: 369
4J.15
Which of the following compounds become less stable with respect to the elements as the temp is raised: (a) PCl5 (b) HCN (c) NO(g) (d)SO2?
- Wed Feb 20, 2019 12:22 am
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2 Thermodynamics
- Replies: 1
- Views: 335
Test 2 Thermodynamics
I read a post saying that thermodynamics will be on test 2 so does that mean isobaric, isothermal, and isochoric equations for test 2?
- Wed Feb 20, 2019 12:19 am
- 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: S value
- Replies: 3
- Views: 937
Re: S value
The larger the molecule, the more ways it can rearrange itself and create different shapes. This increases entropy
- Mon Feb 11, 2019 2:02 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: 7th edition 4C.13
- Replies: 1
- Views: 246
Re: 7th edition 4C.13
I dont think it matters whether you use specific heat of molar heat as long as your consistent in what you use.
For this problem make sure you include the energy it takes to change the solid to a liquid into the equation
For this problem make sure you include the energy it takes to change the solid to a liquid into the equation
- Mon Feb 11, 2019 1:49 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 3/2 R and 5/2 R
- Replies: 3
- Views: 439
Re: 3/2 R and 5/2 R
3/2 R=Cv
5/2R=Cp
this is used in the equation to find heat
q=ncdeltaT
those values only apply to ideal gases
5/2R=Cp
this is used in the equation to find heat
q=ncdeltaT
those values only apply to ideal gases
- Mon Feb 11, 2019 1:46 pm
- Forum: Administrative Questions and Class Announcements
- Topic: MIDTERM 7th ed
- Replies: 1
- Views: 285
Re: MIDTERM 7th ed
It will cover everything until 4J I believe because he said entropy is on the midterm
- Sun Feb 10, 2019 11:24 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Midterm [ENDORSED]
- Replies: 49
- Views: 4692
Re: Midterm [ENDORSED]
If you go to any TA office hour, they will tell you what topics are on the midterm and generally help with any questions you have for the midterm.
- Mon Feb 04, 2019 5:00 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Thermodynamic equations
- Replies: 1
- Views: 288
Thermodynamic equations
I'm struggling with trying to understand which equation to use when I'm reading the homework problems so does anyone have any tips or advice on how to memorize which work,q, or delta u equation to use for the different types of different processes?
- Mon Feb 04, 2019 2:53 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final from 14A
- Replies: 2
- Views: 428
Final from 14A
Does anyone know when we will receive our finals from last quarter?
- Mon Feb 04, 2019 2:51 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Chem 14 BL
- Replies: 5
- Views: 763
Chem 14 BL
Does anyone know if Chem 14BL should be taken with Chem 14C? If not when is it recommended to take Chem 14 BL?
- Mon Jan 28, 2019 11:17 pm
- Forum: Phase Changes & Related Calculations
- Topic: 7th edition 4a.3 part c
- Replies: 1
- Views: 224
7th edition 4a.3 part c
air in a bicycle pump is compressed by pushing in the handle. the inner diameter of the pump is 3.0cm and the pump is depressed 20. cm with a pressure of 2.0 atm. part c) what is the change in internal energy of the system?
- Mon Jan 28, 2019 11:09 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Memorizing bond enthalpies
- Replies: 5
- Views: 609
Re: Memorizing bond enthalpies
What are the common bond enthalpies that I should memorize?
- Mon Jan 28, 2019 11:07 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: HW Week4
- Replies: 4
- Views: 467
HW Week4
So I'm trying to do the problems in the 7th edition book section 4A but I don't really think Lavelle's lecture today or last Friday covered section 4A. Which sections did Lavelle cover so far in thermochemistry so I can do for this week's hw?
- Mon Jan 21, 2019 3:31 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 7th Edit 6D15
- Replies: 1
- Views: 212
Re: 7th Edit 6D15
Since its a weak acid you have to make an ICE Table. You can find the Ka values on the tables in section 6C.
- Mon Jan 21, 2019 3:29 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Test 1 & homework
- Replies: 2
- Views: 276
Re: Test 1 & homework
For problem 6D.13 I used tables 6c1, 6c2, and 6c3 to find ka and kb values
- Mon Jan 21, 2019 3:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 7th Edit 6D.7
- Replies: 1
- Views: 136
Re: 7th Edit 6D.7
For part a with the H+ concentration, you can also use the Table 6c1 and 6c2 to find Ka for HClO. Use ICE table to set up an equation and find the initial concentration of the weak acid
- Mon Jan 14, 2019 3:37 pm
- Forum: Ideal Gases
- Topic: When is pv=nrt used? [ENDORSED]
- Replies: 5
- Views: 526
Re: When is pv=nrt used? [ENDORSED]
You can use PV=NRT in any situation when given any three out of the four: pressure, volume, number of moles, or temperature. R=.08206. In this instance, we use it to convert Kc to Kp or vice versa
- Mon Jan 14, 2019 3:31 pm
- Forum: Ideal Gases
- Topic: Using Kc or Kp
- Replies: 13
- Views: 931
Re: Using Kc or Kp
Kp is for partial pressure with units like atm, bar, torr, etc. Kc is for concentrations and will have mol/L for units
- Mon Jan 14, 2019 3:27 pm
- Forum: General Science Questions
- Topic: Lecture Powerpoints
- Replies: 9
- Views: 708
Re: Lecture Powerpoints
They aren't online so if you ever miss a lecture I would say to either ask a friend for their notes on the lecture or go into his office hours and ask what you topics you missed.
- Wed Jan 09, 2019 11:12 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Giving Qc or Qp when asked for Q
- Replies: 5
- Views: 595
Giving Qc or Qp when asked for Q
For questions like 5G.11 when it asks you to write the reaction quotient Q for a certain equation, does it matter to answer with Qc or Qp?
- Mon Jan 07, 2019 9:41 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Chem Community ID
- Replies: 1
- Views: 187
Re: Chem Community ID
Just change your username by clicking on your name on the top right corner of the page and click user control panel
- Mon Jan 07, 2019 9:40 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Aqueous in K expression
- Replies: 4
- Views: 313
Aqueous in K expression
I know that we don't include solids and liquid in our K expression but what if its aqueous ?
- Wed Dec 05, 2018 1:59 am
- Forum: Identifying Acidic & Basic Salts
- Topic: Proton Transfer Reaction
- Replies: 1
- Views: 215
Re: Proton Transfer Reaction
The cation/anion and water would be the reactants and depending on which reactant is the acid, it will donate the H+ to the base
- Wed Dec 05, 2018 1:55 am
- Forum: Bronsted Acids & Bases
- Topic: J.9
- Replies: 2
- Views: 519
J.9
The question is to identify the salt that is produce from the acid-base neutralization reaction between potassium hydroxide and acetic acid. write the complete ionic equation for each reaction. I am confused as how to approach the problem and what salts can be produced
- Wed Dec 05, 2018 1:52 am
- Forum: Bronsted Acids & Bases
- Topic: Acids
- Replies: 3
- Views: 451
Re: Acids
For our class right now I believe that we are focusing on Bronsted acids
- Mon Nov 26, 2018 10:36 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Cis and Trans
- Replies: 10
- Views: 957
Re: Cis and Trans
The cis configuration is polar which means it can create dipole dipole interactions and create a stronger bond compared to the trans configuration
- Mon Nov 26, 2018 10:30 pm
- Forum: Hybridization
- Topic: Question from textbook
- Replies: 4
- Views: 463
Re: Question from textbook
It has 3 bonds and two lone pairs which means its hybridization is sp3d
- Mon Nov 26, 2018 10:27 pm
- Forum: Lewis Structures
- Topic: Question 3.45
- Replies: 4
- Views: 302
Re: Question 3.45
Nitrogen is in row 2 which means it cant disobey the octet rule. By adding a double bond to chlorine, it would make nitrogen not follow this rule.
- Mon Nov 19, 2018 6:58 pm
- Forum: Hybridization
- Topic: Unhybridized orbitals
- Replies: 10
- Views: 1361
Unhybridized orbitals
Today in lecture Dr. Lavelle talked about unhybridized 2p orbitals but I was unsure of what unhybridized orbitals are and the difference between these and hybridized orbitals.
- Mon Nov 19, 2018 6:41 pm
- Forum: Lewis Structures
- Topic: Lewis Structure of Carbon Monoxide
- Replies: 3
- Views: 444
Re: Lewis Structure of Carbon Monoxide
When drawing lewis structures, it is good to first make sure every element has a complete octet( unless it's in row 3 or after). Then I would start paying attention to how to create the most stable structure.
- Mon Nov 19, 2018 6:37 pm
- Forum: Hybridization
- Topic: D-orbital
- Replies: 5
- Views: 456
Re: D-orbital
Yes Dr. Lavelle said in class that it was fine if you put d before or after the sp
- Tue Nov 13, 2018 5:13 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 3
- Replies: 8
- Views: 1700
Re: Test 3
Test 3 is on the week after Thanksgiving
- Tue Nov 13, 2018 5:11 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Stable Vs. Formal
- Replies: 4
- Views: 1049
Re: Stable Vs. Formal
I think stable charge refers to the formal charge of the most stable structure for the specific molecule
- Tue Nov 13, 2018 4:32 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 5
- Views: 716
Re: Bond Angles
I think bond angles is something you just need to memorize by VSEPR
- Thu Nov 08, 2018 12:50 am
- Forum: Dipole Moments
- Topic: Polar and Nonpolar
- Replies: 7
- Views: 762
Re: Polar and Nonpolar
Polar bonds have an unequal sharing of electrons while nonpolar bonds do have equal sharing
- Thu Nov 08, 2018 12:35 am
- Forum: Lewis Structures
- Topic: Electron Pairs 3.61
- Replies: 2
- Views: 251
Re: Electron Pairs 3.61
To know how to solve the problem, you want to find the most stable lewis structure so guess and check until you find a structure with the lowest formal charge.
- Thu Nov 08, 2018 12:25 am
- Forum: Dipole Moments
- Topic: Dipole-Dipole vs Induced Dipole
- Replies: 5
- Views: 1025
Re: Dipole-Dipole vs Induced Dipole
A dipole induced dipole means that the molecule by itself doesn't have a dipole moment but with the bonding of a second molecule, it will have become dipole,
- Tue Oct 30, 2018 11:25 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2B.1 Part B
- Replies: 2
- Views: 157
2B.1 Part B
The question asks to draw the lewis structure for COCl2. I drew mine and put oxygen in the middle but when I checked the answers carbon was the central atom. How would you be able to know this?
- Tue Oct 30, 2018 11:19 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Cu+ electron configuration
- Replies: 2
- Views: 2015
Re: Cu+ electron configuration
Since the question is asking for the electron configuration of Cu+ it means that Cu lost an electron. Originally it would be [ar]3d84s2 but the 2 electrons from the 4s shell move to the 3d shell making the electron configuration [Ar]3d10
- Tue Oct 30, 2018 11:13 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2A.15
- Replies: 2
- Views: 274
Re: 2A.15
The way I figure it out is I first look at the position of the element. If it is in Group1-3 it will lose the electron, so it will have a positive charge. If its in Group 15-17 it will gain electrons and have a negative charge. The amount of electrons it loses/gains represents the number.
- Mon Oct 22, 2018 11:59 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Test 2 Question
- Replies: 3
- Views: 399
Re: Test 2 Question
Also where did you get the study guide
- Mon Oct 22, 2018 11:59 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Test 2 Question
- Replies: 3
- Views: 399
Re: Test 2 Question
I think it might be talking about e-p distribution and that the p orbital has a 0 probability of electron density
- Mon Oct 22, 2018 11:56 pm
- Forum: Trends in The Periodic Table
- Topic: Periodic Table
- Replies: 2
- Views: 213
Re: Periodic Table
The ionization energy(energy required to lose one electron) of p-block are quite high because they need one more to fill a shell . So they are less reactive than s-blocks in which has a low ionization energy
- Mon Oct 22, 2018 11:53 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Homework 1E.13
- Replies: 1
- Views: 125
Re: Homework 1E.13
The f orbital is included after the 6s2 orbital is filled. When looking at the periodic table, you can see that the f block starts in period 6.
- Tue Oct 16, 2018 5:13 pm
- Forum: Properties of Light
- Topic: property of light
- Replies: 2
- Views: 149
Re: property of light
Photons do influence the amount of energy. Each photon is like a packet of energy so if the light produces a certain amount of photons, the energy radiation is influenced upon that.
- Tue Oct 16, 2018 5:07 pm
- Forum: Properties of Light
- Topic: Change in the electrical field
- Replies: 1
- Views: 186
Re: Change in the electrical field
A lower frequency means a longer wavelength. Since the wavelengths are longer, it allows less oscillations to be completed in a time frame compared to a small wavelength. "extent of the change" means the slope so since the wavelength is longer, the slope changes less.
- Tue Oct 16, 2018 4:59 pm
- Forum: DeBroglie Equation
- Topic: 1B.9
- Replies: 3
- Views: 258
Re: 1B.9
Use the 32J/s to find the total amount of J in 2 seconds. Then use the equation E=(hc)/lambda to find the energy of one photon. With this you should be able to find the number of photons of a violet light. Then you can find the number of moles of photons by using Avogadro's number
- Sun Oct 14, 2018 10:55 am
- Forum: Photoelectric Effect
- Topic: 1B.15 Part C
- Replies: 2
- Views: 177
1B.15 Part C
The velocity of an electron that is emitted from a metallic surface by a photon is 3.6*10^3 km*s^-1. part c. what is the wavelength of the radiation that caused photoejection of the electron? I got part a and b but I'm not really sure how to do this part but I tried both the equations lambda=c/v and...
- Tue Oct 09, 2018 10:08 pm
- Forum: Properties of Light
- Topic: Homework Problem 1A.9
- Replies: 2
- Views: 168
Re: Homework Problem 1A.9
To find the wavelength you first convert the frequency of MHz to Hz. Then using the equation c=(lambda)v, you can find the wavelength.
- Mon Oct 08, 2018 10:44 pm
- Forum: Properties of Light
- Topic: Chapter 1 Question 1.3
- Replies: 3
- Views: 205
Re: Chapter 1 Question 1.3
the "extent of the change" refer to the slopes of the wavelength and because the wavelengths are longer, it allows less oscillations to be completed within a time frame
- Mon Oct 08, 2018 10:36 pm
- Forum: Properties of Light
- Topic: Chem Homework Question Number 1.9
- Replies: 1
- Views: 104
Re: Chem Homework Question Number 1.9
I have the 7th edition and the chart on Table 1A.1 says that a 1m wavelength is both microwave and radio wave
- Wed Oct 03, 2018 10:51 pm
- Forum: Limiting Reactant Calculations
- Topic: Limiting Reactant Steps General Question
- Replies: 3
- Views: 374
Re: Limiting Reactant Steps General Question
When finding empirical or molecular formula, its important that we know the mass percentage of each element. For example, we find the mass percentage is H 4.58%, O 54.5%, and C 40.9%. Since these percentages all equal to 100% it is the easiest procedure to imagine the sample mass being 100g because ...
- Wed Oct 03, 2018 10:45 pm
- Forum: Significant Figures
- Topic: Significant Figures
- Replies: 10
- Views: 2835
Re: Significant Figures
When adding and subtracting, you use the least number of sig figs AFTER the decimal place.
For example, 1.823+9.75=11.57
9.57 has only 2 sig figs after the decimal place which means the answer will only have 2 sig figs after the decimal.
For example, 1.823+9.75=11.57
9.57 has only 2 sig figs after the decimal place which means the answer will only have 2 sig figs after the decimal.
- Wed Oct 03, 2018 10:34 pm
- Forum: SI Units, Unit Conversions
- Topic: Prefixes
- Replies: 6
- Views: 310
Re: Prefixes
In my opinion, the prefixes that will most likely be used is kilo, deci, centi, and milli but like the comment above I think its probably best to memorize them all.
- Tue Oct 02, 2018 9:28 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 416167
Re: Rusty on High School Chem [ENDORSED]
Doing the modules posted on Dr. Lavelle's website is actually really good review. The videos are him teaching the topics/lectures and he gives good and easy examples to follow along.
- Tue Oct 02, 2018 9:27 pm
- Forum: SI Units, Unit Conversions
- Topic: Audio-Visual Focus-Topics, Assessments & Surveys
- Replies: 16
- Views: 1510
Re: Audio-Visual Focus-Topics, Assessments & Surveys
Yea when I did the modules they don't ask for our name or UID so I'm assuming that its just review for self benefit. It was actually a good refresher from summer break.