Search found 64 matches

by Adrienne_4F
Sat Mar 16, 2019 7:47 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 15.76 6th Edition
Replies: 1
Views: 171

15.76 6th Edition

Can someone explain what they did for this problem? I tried to find e^-Ea/RT for each of the activation energies given and compare them but that wasn't the right thing.
by Adrienne_4F
Sat Mar 16, 2019 7:38 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.65 C 6th edition
Replies: 1
Views: 48

15.65 C 6th edition

In the solution manual is says that we expect the forward reaction to go up more than the reverse. How do we know this is true?
by Adrienne_4F
Sat Mar 16, 2019 3:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Midterm, Question 2.B
Replies: 3
Views: 69

Re: Midterm, Question 2.B

Yes it is inverse. It would be 1 over K of the forward reaction.
by Adrienne_4F
Fri Mar 15, 2019 9:31 pm
Forum: Balancing Redox Reactions
Topic: Test 2
Replies: 5
Views: 102

Re: Test 2

Can someone explain this in terms of oxidizing power and how that differs?
by Adrienne_4F
Fri Mar 15, 2019 10:43 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Overall Order
Replies: 5
Views: 215

Re: Overall Order

The overall order can help us determine the units of K and figure out which order reaction equation we should use.
by Adrienne_4F
Fri Mar 15, 2019 10:40 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Confirming a Reaction Mechanism
Replies: 2
Views: 58

Re: Confirming a Reaction Mechanism

I don't think there's necessarily a way to prove that a mechanism is correct but it can be proved incorrect if the mechanisms do not fit the experimental data.
by Adrienne_4F
Thu Mar 14, 2019 9:30 pm
Forum: Administrative Questions and Class Announcements
Topic: lyndon's review?
Replies: 5
Views: 347

Re: lyndon's review?

He will probably make a post on chemistry community so just keep an eye out for it!
by Adrienne_4F
Wed Mar 13, 2019 8:45 pm
Forum: General Rate Laws
Topic: Rate constant units
Replies: 3
Views: 186

Re: Rate constant units

Rate is moles per liter per second
by Adrienne_4F
Wed Mar 13, 2019 8:32 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts vs Intermediates
Replies: 4
Views: 67

Re: Catalysts vs Intermediates

A catalyst is always present as a reactant first, but an intermediate comes up as product first.
by Adrienne_4F
Wed Mar 13, 2019 8:26 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: example
Replies: 2
Views: 59

example

In the example he gave in class about the conversion of oxygen to ozone in lower atmosphere using NO(g), would both NO2 and O be an intermediate and NO is the catalyst?
by Adrienne_4F
Mon Feb 25, 2019 8:18 pm
Forum: Student Social/Study Group
Topic: Lyndon's workshop
Replies: 1
Views: 358

Lyndon's workshop

Hello, if anyone has the answers for Lyndon's review session from week 8 on electrochemistry, please share. It was very full and I couldn't see or hear anything. Thank you. It is greatly appreciated :)
by Adrienne_4F
Mon Feb 25, 2019 7:23 pm
Forum: Balancing Redox Reactions
Topic: Friday lecture
Replies: 1
Views: 52

Friday lecture

In our notes when we're finding E cell, why is the answer .43V even though we have cathode as .77V and anode as -.34 V? shouldn't it be .77-(-.34)=?
by Adrienne_4F
Wed Feb 13, 2019 11:42 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: 9.35
Replies: 2
Views: 233

9.35

Why does A, the monatomic gas have a larger enthalpy change than a diatomic gas?
by Adrienne_4F
Tue Feb 12, 2019 9:42 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.13
Replies: 2
Views: 62

9.13

For change in entropy for change in temperature, why does it use R when the equation for delta S change in temp is delta S=nClnT2/T1?
by Adrienne_4F
Tue Feb 12, 2019 5:14 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy of formation
Replies: 2
Views: 91

Enthalpy of formation

What other molecules besides O2 and N2 have o enthalpy of formation?
by Adrienne_4F
Tue Feb 12, 2019 4:35 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 8.45
Replies: 2
Views: 68

8.45

How do we know that the delta H given is KJ/ mol? Is it always assumed that it's KJ/mol?
by Adrienne_4F
Tue Feb 05, 2019 5:40 pm
Forum: Calculating Work of Expansion
Topic: Work
Replies: 3
Views: 86

Work

In the book, it talks about how a gas might push a piston into a vacuum in which no work is being doing. What does it mean by pushing into a vacuum?
by Adrienne_4F
Mon Feb 04, 2019 8:08 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Open vs Closed Systems
Replies: 4
Views: 86

Re: Open vs Closed Systems

Hi, it might be helpful to look at question 8.1. They ask you to identify which systems are open, closed, or isolated.
by Adrienne_4F
Mon Feb 04, 2019 6:17 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: reaction constant P
Replies: 3
Views: 73

reaction constant P

Why is PdeltaV insignificant if it involves liquids and solids?
by Adrienne_4F
Mon Feb 04, 2019 6:15 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: U
Replies: 7
Views: 134

U

What does it mean by U is a state property?
by Adrienne_4F
Mon Feb 04, 2019 6:13 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: molecules
Replies: 1
Views: 48

molecules

In our lecture notes, what does it mean by "molecules in gaseous phase occupy many more states than liquid and solid?"
by Adrienne_4F
Tue Jan 29, 2019 3:02 pm
Forum: Phase Changes & Related Calculations
Topic: temperature
Replies: 3
Views: 57

temperature

In melting and boiling, why does the temperature of a sample stay constant even though heat is being added?
by Adrienne_4F
Tue Jan 29, 2019 3:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: enthalpy
Replies: 4
Views: 68

enthalpy

What does it mean by enthalpy is a state function ?
by Adrienne_4F
Tue Jan 22, 2019 5:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE chart
Replies: 2
Views: 52

Re: ICE chart

Products will always be plus if you start out with no products. If the reaction is going forward, then products will be plus but if the reaction is going backwards, the reactants will be plus.
by Adrienne_4F
Tue Jan 22, 2019 5:24 pm
Forum: Ideal Gases
Topic: OH and H3O
Replies: 10
Views: 401

Re: OH and H3O

When you have an acid reacting with water, you'll result in H3O+ because the atom donates an H to water. With bases, you'll get OH- because that atom will take an H from water.
by Adrienne_4F
Tue Jan 22, 2019 5:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: autoprotolysis
Replies: 1
Views: 41

autoprotolysis

What other examples of autoprotolysis are there besides the example with water? What aspects of autoprotolysis do we need to know for Test 1?
by Adrienne_4F
Thu Jan 17, 2019 10:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Question 11.89
Replies: 1
Views: 56

Question 11.89

How do we know that the coefficient for A and C is 2 based on the graph that is given?
by Adrienne_4F
Mon Jan 14, 2019 9:31 pm
Forum: Ideal Gases
Topic: pressure
Replies: 7
Views: 151

pressure

Can pressure be changed without changing the volume? If yes, how?
by Adrienne_4F
Thu Jan 10, 2019 1:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: H2O
Replies: 5
Views: 76

H2O

If water is in gas form, will it be included in the equilibrium equation?
by Adrienne_4F
Thu Jan 10, 2019 12:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Keq vs. Kc vs. Kp
Replies: 3
Views: 1592

Keq vs. Kc vs. Kp

What is the difference between Keq, Kc, and Kp? Does it matter if we use Keq for Kp since Keq is the general equilibrium constant?
by Adrienne_4F
Mon Jan 07, 2019 7:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ideal Gas Law
Replies: 1
Views: 48

Ideal Gas Law

What does R represent in PV=nRT?
by Adrienne_4F
Sat Dec 08, 2018 9:47 pm
Forum: Amphoteric Compounds
Topic: amphoteric
Replies: 2
Views: 210

amphoteric

If a compound is amphoteric, is it also amphiprotic?
by Adrienne_4F
Sat Dec 08, 2018 7:09 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH of acids
Replies: 13
Views: 314

pH of acids

Why does a strong acid have a smaller pH compared to a weak acid that has a higher pH?
by Adrienne_4F
Sat Dec 01, 2018 1:01 pm
Forum: Lewis Acids & Bases
Topic: Lewis and Bronsted
Replies: 8
Views: 187

Lewis and Bronsted

What's the difference between a Lewis and Bronsted Acid and Base?
by Adrienne_4F
Sat Dec 01, 2018 1:00 pm
Forum: Naming
Topic: Roman Numeral
Replies: 5
Views: 132

Roman Numeral

Some of the names of molecules have roman numerals. How do we know which ones have roman numerals and what the roman numerals are?
by Adrienne_4F
Sat Dec 01, 2018 12:58 pm
Forum: Biological Examples
Topic: Heme structures
Replies: 1
Views: 77

Heme structures

Can someone explain exactly what heme structures are or what heme means? Thank you
by Adrienne_4F
Sat Dec 01, 2018 12:57 pm
Forum: Naming
Topic: For the Final
Replies: 1
Views: 33

Re: For the Final

I assume you have to know the ones that come up in examples a lot, like hydroxide, ammonia, oxide, etc.
by Adrienne_4F
Sat Dec 01, 2018 12:22 pm
Forum: General Science Questions
Topic: Final Review
Replies: 4
Views: 163

Re: Final Review

Hi! I really enjoy going to Lyndon's workshops. He's super helpful and makes things very easy to understand. 10/10 would recommend :)
by Adrienne_4F
Tue Nov 27, 2018 1:40 pm
Forum: Hybridization
Topic: pi bonds
Replies: 3
Views: 92

pi bonds

How do we explain pi bonds using hybridization? There was an example from class for C2H4, but I don't understand it.
by Adrienne_4F
Tue Nov 27, 2018 1:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T shaped
Replies: 6
Views: 131

Re: T shaped

There is repulsion due to the two lone pairs, therefore they will push the atoms closer together, making a T shape rather than a trigonal planar.
by Adrienne_4F
Tue Nov 27, 2018 1:27 pm
Forum: Dipole Moments
Topic: 4.29
Replies: 3
Views: 76

4.29

In question 4.29, why does 1 have the largest dipole moment although the distance between the two chlorines is the smallest?
by Adrienne_4F
Tue Nov 27, 2018 1:26 pm
Forum: Dipole Moments
Topic: dipole moment
Replies: 2
Views: 78

dipole moment

What exactly does the dipole moment tell us and how do we determine whether a dipole moment is large or small?
by Adrienne_4F
Tue Nov 27, 2018 1:24 pm
Forum: Hybridization
Topic: hybridization
Replies: 3
Views: 81

hybridization

In our notes, professor wrote the hybridization as 2sp, 2sp2, etc but in the the textbook they write it just as sp, sp2, etc.. what is the difference?
by Adrienne_4F
Wed Nov 14, 2018 11:08 pm
Forum: Dipole Moments
Topic: Van der Waals
Replies: 4
Views: 125

Re: Van der Waals

Yes, all molecules have this bond. In our notes, it states that all dispersion interactions are always present and active and Van der Waals is just another name for dispersion.
by Adrienne_4F
Wed Nov 14, 2018 11:06 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: polar vs nonpolar
Replies: 6
Views: 194

polar vs nonpolar

How can we differentiate between a polar and nonpolar molecule?
by Adrienne_4F
Wed Nov 14, 2018 11:05 pm
Forum: Bond Lengths & Energies
Topic: Bond Length
Replies: 9
Views: 226

Re: Bond Length

Like others have said, its the average of the lengths. so if you had 2 single bonds and one double bond, you would add all three and divide by 3.
by Adrienne_4F
Wed Nov 14, 2018 4:24 pm
Forum: Lewis Structures
Topic: Boron Trifluoride
Replies: 8
Views: 183

Boron Trifluoride

In our notes from October 31st, we drew boron trifluoride, but boron only has 6 electrons, why? Don't all elements need 8 electrons?
by Adrienne_4F
Tue Nov 13, 2018 6:57 pm
Forum: Octet Exceptions
Topic: octet exceptions
Replies: 2
Views: 111

octet exceptions

Can someone explain why some of these atoms have octet exceptions? what makes them different from others?
by Adrienne_4F
Wed Oct 31, 2018 6:56 pm
Forum: Trends in The Periodic Table
Topic: Electron affinity
Replies: 5
Views: 103

Electron affinity

Can someone explain electron affinity and how it applies to the periodic table?
by Adrienne_4F
Wed Oct 31, 2018 6:54 pm
Forum: *Black Body Radiation
Topic: Midterm
Replies: 4
Views: 279

Re: Midterm

If there are any black body radiation questions, what might we need to know? Any ideas?
by Adrienne_4F
Wed Oct 31, 2018 6:53 pm
Forum: *Shrodinger Equation
Topic: Midterm
Replies: 6
Views: 404

Re: Midterm

What kind of general concepts should we understand in terms of shrodinger's equation? Are there any good examples in the textbook that might be useful?
by Adrienne_4F
Wed Oct 24, 2018 3:58 pm
Forum: Trends in The Periodic Table
Topic: Removing 2nd Electron
Replies: 9
Views: 189

Re: Removing 2nd Electron

Removing the second electron is more difficult because the atom pulls on the second electron stronger. In the example he gave us, after removing one electron from copper, it became Cu+, therefore the nuclear charge is stronger than Cu.
by Adrienne_4F
Mon Oct 22, 2018 7:03 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals
Replies: 2
Views: 54

Orbitals

Will we need to know the drawings for f- orbital?
by Adrienne_4F
Mon Oct 22, 2018 7:00 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Building- Up Principle
Replies: 5
Views: 128

Building- Up Principle

Why is copper [Ar] 3d^10 4s^1, not [Ar] 3d^9 4s^2? Same for chromium which is [Ar] 3d^5 4s^1, not [Ar] 3d^4 4s^2? I remember he mentioned it's so that the element is more stable. What does that mean?
by Adrienne_4F
Wed Oct 17, 2018 6:40 pm
Forum: *Shrodinger Equation
Topic: Schrodinger Equation
Replies: 2
Views: 118

Schrodinger Equation

I'm very confused. What does the equation actually help us find? Also, what do orbitals have to do with the equation?
by Adrienne_4F
Tue Oct 16, 2018 4:09 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Change in energy
Replies: 2
Views: 49

Change in energy

Why is delta E negative when we go from the fourth to the second principal quantum level?
by Adrienne_4F
Tue Oct 16, 2018 3:42 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Planck's Constant
Replies: 4
Views: 63

Planck's Constant

When we're using Planck's constant, do we use 6.626 X 10^-34 or 6.63 X 10^-34? Professor switches off between the two in the lecture notes.
by Adrienne_4F
Wed Oct 10, 2018 4:06 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Threshold Energy
Replies: 4
Views: 61

Threshold Energy

Can someone explain what threshold energy is and how it is relevant to today's lecture? Thank you.
by Adrienne_4F
Wed Oct 10, 2018 1:09 pm
Forum: Properties of Light
Topic: Planck's constant
Replies: 5
Views: 153

Re: Planck's constant

E is the energy of the particle or photon, with the units joules.
H is just Planck's constant, which is 6.63 X 10^-34 joules X second.
V is the frequency, with the units Hertz or S^-1.

Energy and frequency are directly proportional, therefore when frequency increases, energy increases.
by Adrienne_4F
Mon Oct 08, 2018 8:40 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 2
Views: 70

Photoelectric Effect

Hi, I'm a little confused. When Professor Lavelle explained higher energy in the lecture he did not mean higher intensity correct? A higher intensity would generate more protons but not stronger protons. A higher energy would generate stronger protons. Is my understanding correct or? Also what is th...
by Adrienne_4F
Thu Oct 04, 2018 3:39 pm
Forum: Empirical & Molecular Formulas
Topic: How to write empirical/ molecular formulas
Replies: 3
Views: 99

How to write empirical/ molecular formulas

How do we know what order to write the empirical or molecular formula in?
For example, F17. In the solution manual they wrote Os before C and H. How would we know that?
by Adrienne_4F
Thu Oct 04, 2018 3:31 pm
Forum: Significant Figures
Topic: Molar Mass
Replies: 5
Views: 133

Molar Mass

When we're using the molar mass, should we estimate according to how many sig figs are in the problem or do we use the most accurate molar mass we have?

Ex. problem asks to gives 3.45 g. of carbon. Would we use 12.0 or 12.011 for the molar mass?
by Adrienne_4F
Thu Oct 04, 2018 3:16 pm
Forum: SI Units, Unit Conversions
Topic: SI Units
Replies: 7
Views: 169

SI Units

Hi! I'm a little confused about the SI unit for mass. In the lecture, professor said that the SI unit for mass was kilograms. When we're writing our answers, do we convert our answers from grams to kilograms? Thank you!

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