Search found 62 matches
- Mon Mar 11, 2019 2:48 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Frequency Factor
- Replies: 5
- Views: 557
Frequency Factor
What does the frequency factor mean?
- Mon Mar 11, 2019 2:44 pm
- Forum: First Order Reactions
- Topic: Half-life Clarification
- Replies: 5
- Views: 627
Re: Half-life Clarification
Yes. The half life equation depends on the reaction order.
- Mon Mar 11, 2019 12:14 pm
- Forum: Zero Order Reactions
- Topic: Zero Order Reaction
- Replies: 5
- Views: 895
Zero Order Reaction
What is an example of a zero order reaction?
- Wed Mar 06, 2019 2:21 pm
- Forum: Zero Order Reactions
- Topic: General Meaning of "Zero Order" Reactions
- Replies: 7
- Views: 750
Re: General Meaning of "Zero Order" Reactions
In a zero order reaction, the rate of the reaction does not depend on the concentration of the reactant.
- Wed Mar 06, 2019 2:19 pm
- Forum: Second Order Reactions
- Topic: graph for second order
- Replies: 7
- Views: 803
Re: graph for second order
The graph for the second order looks like a line with a positive slope.
- Wed Mar 06, 2019 9:20 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: E cell
- Replies: 5
- Views: 503
E cell
What is the difference between E cell and E^o ?
- Tue Feb 26, 2019 4:51 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L9
- Replies: 1
- Views: 175
6L9
The equation for the anode part of the reaction is Fe^2+(aq)--> Fe^3+(aq) +1e-
Why does Fe^3+ come before Fe^2+ in the cell diagram?
Pt(s)I Fe^3+(aq), Fe^2+(aq)II
Why does Fe^3+ come before Fe^2+ in the cell diagram?
Pt(s)I Fe^3+(aq), Fe^2+(aq)II
- Tue Feb 26, 2019 12:49 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff Equation
- Replies: 3
- Views: 690
Re: Van't Hoff Equation
K varies by temperature, so the Van Hoff equation is used to calculate K at a different temperature. If you know delta H and the K value at one temperature, you can use the equation to find K at a different temperature.
- Tue Feb 26, 2019 9:38 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: 6L.3 7th Edition: Solve for E° values?
- Replies: 1
- Views: 272
Re: 6L.3 7th Edition: Solve for E° values?
You can find the values in Appendix 2B.
- Mon Feb 25, 2019 2:23 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Voltage
- Replies: 1
- Views: 226
Re: Voltage
Voltage can be negative, but if it is negative the battery will not work.
- Wed Feb 20, 2019 8:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Midterm Ice Table
- Replies: 6
- Views: 701
Re: Midterm Ice Table
You can solve an equilibrium problem without using an approximation. Approximations act like a short cut. If the questions stated to not use an approximation, you would do the problem using the quadratic formula.
- Wed Feb 20, 2019 4:49 pm
- Forum: Balancing Redox Reactions
- Topic: Salt Bridge
- Replies: 4
- Views: 441
Salt Bridge
What is the purpose of the salt bridge?
- Wed Feb 20, 2019 4:44 pm
- Forum: Balancing Redox Reactions
- Topic: Determining Oxidation State
- Replies: 2
- Views: 281
Re: Determining Oxidation State
You know Fe lost 5 electrons because originally there are 5 Fe 2+ which has a total charge of 10+. After the reaction there is 5 Fe 3+ which has a total charge of 15+. In order to go from 10+ to 15+, 5 electrons must be lost.
- Mon Feb 11, 2019 10:53 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Ideal Gas
- Replies: 2
- Views: 289
Ideal Gas
What does an ideal gas mean?
- Mon Feb 11, 2019 10:41 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Delta H
- Replies: 3
- Views: 483
Re: Delta H
Delta H is equal to q when there is constant pressure.
- Mon Feb 11, 2019 12:13 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Units for enthalpy
- Replies: 6
- Views: 766
Re: Units for enthalpy
You can use either J or kJ. Both will be accepted on the test, but when the amount of J is above 1000, it is usually written in kJ.
- Mon Feb 04, 2019 7:39 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: U
- Replies: 7
- Views: 657
Re: U
U is a state property because the value is determined by its current state. A state property is not dependent on the path taken to obtain that state.
- Mon Feb 04, 2019 2:02 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Degeneracy
- Replies: 5
- Views: 547
Re: Degeneracy
Degeneracy is the number of ways of achieving a given energy state.
- Mon Feb 04, 2019 1:59 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Equation for internal energy
- Replies: 2
- Views: 282
Re: Equation for internal energy
q is the heat exchanged between the system and its surroundings.
- Tue Jan 29, 2019 6:09 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 7th Ed. 4C3
- Replies: 2
- Views: 291
Re: 7th Ed. 4C3
The solution manual says that in part a) Tf= 343K and in part b) Tf= 373K.
- Tue Jan 29, 2019 6:02 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calorimeter
- Replies: 4
- Views: 453
Calorimeter
What is the purpose of a calorimeter and how does it work?
- Mon Jan 28, 2019 7:54 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard State
- Replies: 2
- Views: 273
Standard State
When finding the standard enthalpy of an equation, how can you make sure that everything is in standard state?
- Tue Jan 22, 2019 3:49 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 6D.3 7th edition
- Replies: 3
- Views: 326
Re: 6D.3 7th edition
Use an ICE chart and find the concentration of H30+ by using the given pH.
- Tue Jan 22, 2019 12:38 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Endothermic vs. Exothermic
- Replies: 8
- Views: 821
Endothermic vs. Exothermic
What is the difference between an endothermic reaction and an exothermic reaction?
- Tue Jan 22, 2019 12:34 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Sig Figs of pKa
- Replies: 2
- Views: 5699
Re: Sig Figs of pKa
It is the same rule for pKa because the rule applies whenever you take the log of something.
- Wed Jan 16, 2019 9:35 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle- example from class
- Replies: 3
- Views: 309
Re: Le Chatelier's Principle- example from class
If we increase N2 the reaction will proceed to the right so more product is formed.
If we increase NH3 the reaction will proceed to the left so more reactants are formed.
If we decrease H2 the reaction will proceed to the left so more reactants are formed.
If we increase NH3 the reaction will proceed to the left so more reactants are formed.
If we decrease H2 the reaction will proceed to the left so more reactants are formed.
- Wed Jan 16, 2019 12:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Acids
- Replies: 6
- Views: 523
Acids
How can you tell what is a weak acid vs. what is a strong acid?
- Tue Jan 15, 2019 9:40 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction Quotient
- Replies: 10
- Views: 819
Re: Reaction Quotient
K is used to describe a reaction that is at equilibrium. The reaction quotient is used to describe a reaction that is not at equilibrium. If Q is equal to K, the reaction is at equilibrium.
- Wed Jan 09, 2019 6:41 pm
- Forum: Ideal Gases
- Topic: Reaction Quotient
- Replies: 4
- Views: 455
Re: Reaction Quotient
The Reaction Quotient is calculated the same way that K is calculated. The equation is Q=[Products]/[Reactants]. The reaction quotient is used to determine which direction the reaction will proceed.
- Wed Jan 09, 2019 10:08 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction Quotient
- Replies: 5
- Views: 440
Re: Reaction Quotient
K is used to describe a reaction at equilibrium. The reaction quotient is used to describe a reaction that is not at equilibrium. If the reaction quotient is equal to K, you know that the reaction is at equilibrium.
- Tue Jan 08, 2019 6:56 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc vs. Kp
- Replies: 7
- Views: 688
Kc vs. Kp
How do we know when to write the equation for Kc vs. Kp when the question just asks to find the expression for K like in question 5G3?
- Mon Dec 03, 2018 8:27 pm
- Forum: Conjugate Acids & Bases
- Topic: conjugate acids
- Replies: 3
- Views: 582
Re: conjugate acids
The formula of the conjugate acid is CH3NH3+. You just add an H+.
- Mon Dec 03, 2018 8:23 pm
- Forum: Lewis Acids & Bases
- Topic: Naming Acids
- Replies: 2
- Views: 403
Naming Acids
How can you determine the name of an acid?
- Mon Dec 03, 2018 11:19 am
- Forum: Balancing Chemical Reactions
- Topic: Aqueous compounds
- Replies: 5
- Views: 603
Aqueous compounds
How can you tell if a compound is aqueous?
- Tue Nov 27, 2018 2:46 pm
- Forum: Hybridization
- Topic: 2F.13 7th Ed
- Replies: 4
- Views: 485
Re: 2F.13 7th Ed
The hybridization of CH2 and CH are sp2 because there are only three areas of electron density surrounding them. The C in CH2 has one bond connecting each of the two hydrogens and a double bond connecting it to the other carbon. The C in CH has one bond connecting it to the hydrogen, one double bond...
- Mon Nov 26, 2018 11:16 am
- Forum: Bond Lengths & Energies
- Topic: 7th Edition 2D.13
- Replies: 1
- Views: 273
Re: 7th Edition 2D.13
You know the order because triple bonds are shorter than double bonds, and double bonds are shorter than single bonds.
- Mon Nov 26, 2018 9:39 am
- Forum: Hybridization
- Topic: Just Kind of Confused
- Replies: 13
- Views: 1058
Re: Just Kind of Confused
You can write it either way. Both are considered correct.
- Tue Nov 20, 2018 12:56 pm
- Forum: Lewis Structures
- Topic: Electronegativity
- Replies: 4
- Views: 450
Re: Electronegativity
The atom with the smallest electronegativity is typically the central atom because atoms with high electronegativity are more reluctant to share their electrons with other atoms and instead keep their lone pairs.
- Mon Nov 19, 2018 2:45 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 3
- Views: 140
Bond Angles
What are the bond angles of a seesaw?
- Mon Nov 19, 2018 9:40 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent vs. Angular
- Replies: 3
- Views: 351
Bent vs. Angular
Is having a molecular shape that is bent the same as having a molecular shape that is angular?
- Thu Nov 15, 2018 11:43 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular shape
- Replies: 3
- Views: 388
Molecular shape
How does the molecular shape affect the boiling point?
- Tue Nov 13, 2018 11:15 am
- Forum: Dipole Moments
- Topic: Van der Waals
- Replies: 4
- Views: 428
Van der Waals
Do all molecules have Van der Waals forces?
- Mon Nov 12, 2018 7:40 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic Compounds 2D3
- Replies: 2
- Views: 492
Re: Ionic Compounds 2D3
A rough guideline to determine if something is an ionic bond is to use electronegativity. If the electronegativity difference is greater than 2, it is likely an ionic bond. BaBr2 is more ionic than BeBr2 and BBr3 because the electronegativity difference is greater.
- Thu Nov 08, 2018 3:57 pm
- Forum: Dipole Moments
- Topic: Polarizability
- Replies: 5
- Views: 390
Polarizability
How can you tell the polarizability of a molecule?
- Wed Nov 07, 2018 11:18 am
- Forum: Dipole Moments
- Topic: Interaction Potential Energy
- Replies: 1
- Views: 176
Interaction Potential Energy
What is interaction potential energy? Why is it always negative?
- Tue Nov 06, 2018 11:41 am
- Forum: Octet Exceptions
- Topic: Central atoms with more than 8 electrons
- Replies: 3
- Views: 1775
Re: Central atoms with more than 8 electrons
Any atom that is in the third period or below can have an expanded octet.
- Wed Oct 31, 2018 5:10 pm
- Forum: Octet Exceptions
- Topic: Coordinate Covalent Bond
- Replies: 2
- Views: 355
Coordinate Covalent Bond
What is a coordinate covalent bond? How does it relate to octet exceptions?
- Tue Oct 30, 2018 2:41 pm
- Forum: Resonance Structures
- Topic: Lengths of bonds
- Replies: 3
- Views: 278
Lengths of bonds
Why are double bonds shorter than single bonds?
- Mon Oct 29, 2018 9:35 am
- Forum: Trends in The Periodic Table
- Topic: Electron affinity
- Replies: 3
- Views: 538
Electron affinity
What is the difference between electron affinity and electronegativity?
- Tue Oct 23, 2018 11:04 am
- Forum: Administrative Questions and Class Announcements
- Topic: TEST 3 during Thanksgiving week?
- Replies: 5
- Views: 611
Re: TEST 3 during Thanksgiving week?
I think he updated the test and exam schedule because now it says Test 3 starts Tuesday November 27.
- Mon Oct 22, 2018 10:38 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 39643
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Can anyone explain how to do number 7 on the Quantum World Worksheet 2 the way Professor Lavelle showed us in class? Here is the question. An excited hydrogen atom emits light with a frequency of 1.14 x 10^14 Hz to reach the energy level for which n=4. In what principle quantum level did the electro...
- Mon Oct 22, 2018 8:46 pm
- Forum: Properties of Electrons
- Topic: Predicting Nodal Planes
- Replies: 2
- Views: 441
Re: Predicting Nodal Planes
There are always 3 nodal planes for f orbitals.
- Thu Oct 18, 2018 3:24 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal Planes
- Replies: 1
- Views: 191
Nodal Planes
How can you tell which orbitals have nodal planes?
- Wed Oct 17, 2018 11:55 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Problem 1D 13
- Replies: 2
- Views: 289
Re: Problem 1D 13
Question 1D 13 part d asks how many subshells are there in the shell with n=4. In this case there would be four subshells (4s, 4p, 4d, and 4f).
- Tue Oct 16, 2018 6:00 pm
- Forum: DeBroglie Equation
- Topic: Mass of electrons
- Replies: 3
- Views: 356
Re: Mass of electrons
I think it will be given.
- Fri Oct 12, 2018 4:33 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Audio Visual Question 28
- Replies: 1
- Views: 112
Audio Visual Question 28
The meter was defined in 1963 as 1,650,763.73 wavelengths of radiation emitted by krypton-86. What is the wavelength of this krypton-86 radiation?
- Wed Oct 10, 2018 11:26 am
- Forum: Properties of Light
- Topic: Homework Question 1A15
- Replies: 3
- Views: 237
Homework Question 1A15
In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6nm. Determine the values of n for the initial and final energy levels of the electron during the emissions of energy that leads to this spectral line.
- Tue Oct 09, 2018 5:20 pm
- Forum: Properties of Light
- Topic: Homework Problem 1B9
- Replies: 1
- Views: 153
Homework Problem 1B9
A lamp rated at 32. W (1W=1J/s) emits violet light of wavelength 420nm. How many moles of photons are emitted in 2.0 seconds?
- Sun Oct 07, 2018 2:55 pm
- Forum: Einstein Equation
- Topic: Homework Question 1B7b
- Replies: 2
- Views: 531
Homework Question 1B7b
Sodium vapor lamps emit yellow light of wavelength 589nm. How much energy is emitted by 5.00 mg of sodium atoms?
- Wed Oct 03, 2018 8:23 pm
- Forum: SI Units, Unit Conversions
- Topic: Naming Compounds
- Replies: 9
- Views: 850
Naming Compounds
Can someone explain how to write the formula of compounds.
For example, in question E9 it asks you to write the formula for magnesium sulfate heptahydrate.
For example, in question E9 it asks you to write the formula for magnesium sulfate heptahydrate.
- Mon Oct 01, 2018 11:18 am
- Forum: Limiting Reactant Calculations
- Topic: Audio Visual Question 22
- Replies: 3
- Views: 484
Audio Visual Question 22
According to the following equation 0.750 g of C6H9Cl3 is mixed with 1.000 kg of AgNO3 in a flask of water. A white solid, AgCl, completely precipitates out. What is the mass of AgCl produced? C6H9Cl3 + 3AgNO3 --> AgCl + C6H9(NO3)3 Molar Mass : C6H9Cl3 (187.50 g/mol), 3AgNO3 (169.88 g/mol), AgCL (14...
- Sun Sep 30, 2018 9:26 am
- Forum: SI Units, Unit Conversions
- Topic: How does grading for discussion posts work?
- Replies: 80
- Views: 9332
Re: How does grading for discussion posts work?
You can receive a maximum of 3 points per week, and you get a point every time you make a post or reply to a post. If you post 3 times per week, you will receive full credit.