Search found 67 matches
- Sat Mar 16, 2019 6:41 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: K'
- Replies: 4
- Views: 538
Re: K'
k' is the reverse reaction constant and can be used in the equation K = k/k'
- Sat Mar 16, 2019 6:38 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Exothermic vs Endothermic
- Replies: 6
- Views: 653
Re: Exothermic vs Endothermic
Ea forward > Ea Reverse: Endothermic
Ea forward < Ea Reverse: Exothermic
Ea forward < Ea Reverse: Exothermic
- Sat Mar 16, 2019 6:34 pm
- Forum: Second Order Reactions
- Topic: reaction intermediate
- Replies: 4
- Views: 797
Re: reaction intermediate
The intermediate is the molecule formed in step 1 that is then used in step 2.
- Sat Mar 16, 2019 6:31 pm
- Forum: Second Order Reactions
- Topic: 2nd order rates
- Replies: 6
- Views: 835
Re: 2nd order rates
Yes, because total rate order is found by adding the exponents of the reactants.
- Sat Mar 16, 2019 6:29 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Negative Order
- Replies: 4
- Views: 808
Re: Negative Order
A negative order signifies that the concentration of the reactant inversely affects the reaction rate.
- Sat Mar 16, 2019 6:27 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: mmol vs mol
- Replies: 6
- Views: 1074
Re: mmol vs mol
As long as the conversion is correct it should not matter. However, the best practice may be to give your answer in the units that were stated in the question.
- Sat Mar 16, 2019 6:25 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: instantaneous and unique rate
- Replies: 6
- Views: 1244
Re: instantaneous and unique rate
Unique Rate: Rate divided by stoichiometric coefficient
Instantaneous: The slope of the tangent line at a specific moment
Instantaneous: The slope of the tangent line at a specific moment
- Sat Mar 16, 2019 6:23 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Molecularity
- Replies: 3
- Views: 769
Re: Molecularity
By looking at the number of molecules participating in the rate determining step of the reaction you can determine molecularity.
- Sat Mar 16, 2019 6:20 pm
- Forum: First Order Reactions
- Topic: Writing First Order Reactions
- Replies: 4
- Views: 733
Re: Writing First Order Reactions
The one would be implied just as it would be in a math class.
- Sat Mar 16, 2019 6:19 pm
- Forum: First Order Reactions
- Topic: Half-life Formulas
- Replies: 2
- Views: 579
Re: Half-life Formulas
It's best to understand how you would get to the half life to help with the conceptual aspects of this section.
- Sat Mar 16, 2019 6:16 pm
- Forum: First Order Reactions
- Topic: half life
- Replies: 3
- Views: 590
Re: half life
Because when the first order half-life equation is derived the initial concentration terms will cancel out.
- Tue Mar 05, 2019 2:44 pm
- Forum: Van't Hoff Equation
- Topic: K value- Temp
- Replies: 6
- Views: 1029
Re: K value- Temp
Temperature is the only thing that can change the value of K.
- Tue Mar 05, 2019 2:42 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Temperature and Equilibrium
- Replies: 3
- Views: 372
Re: Temperature and Equilibrium
Endothermic Reaction: Increase in temperature will cause the reaction to shift to the right.
Exothermic Reaction: Increase in temperature will cause the reaction to shift to the left.
Exothermic Reaction: Increase in temperature will cause the reaction to shift to the left.
- Tue Mar 05, 2019 2:37 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Systems
- Replies: 6
- Views: 981
Re: Systems
Open systems: Exchange both matter and energy with the surroundings
Closed systems: Exchange just energy
Isolated systems: Neither heat nor matter can be exchanged
Closed systems: Exchange just energy
Isolated systems: Neither heat nor matter can be exchanged
- Tue Mar 05, 2019 2:32 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Constant Vol.
- Replies: 8
- Views: 1067
Re: Constant Vol.
Yes, when volume does not change work or "w" is equal to 0.
- Tue Mar 05, 2019 2:30 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Cp vs Cv
- Replies: 7
- Views: 1102
Re: Cp vs Cv
The problem should give you enough information to determine which to use.
- Tue Mar 05, 2019 2:29 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Ecell
- Replies: 13
- Views: 1505
Re: Ecell
Ecell is calculated by subtracting the reduction potential of the oxidized half reaction (Anode) from the reduction potential of the reduced half reaction (Cathode).
- Tue Mar 05, 2019 2:26 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Ideal gases
- Replies: 4
- Views: 494
Re: Ideal gases
You should use 5/2R if pressure is constant and 3/2R if volume is constant.
- Tue Mar 05, 2019 2:23 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Temperature
- Replies: 3
- Views: 381
Re: Temperature
Try not to round to sig figs until the end of the problem to ensure accurate answers.
- Tue Mar 05, 2019 2:22 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies
- Replies: 8
- Views: 887
Re: Bond Enthalpies
Yes, the bonds broken release energy (reactants) and the bonds formed require energy (products).
- Tue Mar 05, 2019 2:19 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: equations for q
- Replies: 9
- Views: 894
Re: equations for q
q=nC(delta)T when given # of moles
q=mCdeltaT when given mass
q=C(delta)T when moles = 1
q=mCdeltaT when given mass
q=C(delta)T when moles = 1
- Tue Mar 05, 2019 2:16 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam vs Boiling Water
- Replies: 8
- Views: 1199
Re: Steam vs Boiling Water
Because the steam has more heat and therefore a higher enthalpy.
- Tue Mar 05, 2019 2:14 pm
- Forum: Phase Changes & Related Calculations
- Topic: Slope of heating curve
- Replies: 8
- Views: 3367
Re: Slope of heating curve
Because the substance can withstand more heat the slope will be much less steep.
- Tue Mar 05, 2019 2:12 pm
- Forum: Phase Changes & Related Calculations
- Topic: reversible processes and equilibrium
- Replies: 4
- Views: 502
Re: reversible processes and equilibrium
Yes, the reaction would be in equilibrium if it was reversible.
- Tue Mar 05, 2019 2:09 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Delta G rules
- Replies: 8
- Views: 786
Re: Delta G rules
Delta G > 0 ; Not spontaneous
Delta G < 0 ; Spontaneous
Delta G = 0 ; Equilibrium
Delta G < 0 ; Spontaneous
Delta G = 0 ; Equilibrium
- Tue Mar 05, 2019 2:06 pm
- Forum: Balancing Redox Reactions
- Topic: oxidation states
- Replies: 4
- Views: 584
Re: oxidation states
Oxidation state is the number of electrons an element needs to gain or lose to reach a neutral state and can be found by using the periodic table.
- Tue Mar 05, 2019 2:04 pm
- Forum: Balancing Redox Reactions
- Topic: Strength of reducing agent
- Replies: 10
- Views: 1980
Re: Strength of reducing agent
The more negative the value of Ecell is the stronger the reducing agent is.
- Tue Mar 05, 2019 2:03 pm
- Forum: Balancing Redox Reactions
- Topic: OH-
- Replies: 5
- Views: 581
Re: OH-
You would use OH- when balancing the hydrogens in a basic solution.
- Tue Mar 05, 2019 2:01 pm
- Forum: Balancing Redox Reactions
- Topic: Acidic vs basic solutions
- Replies: 10
- Views: 1049
Re: Acidic vs basic solutions
For an acidic solution you would use H20 and H+ to balance the hydrogens and oxygens while in a basic solution you would use H20 and OH- to balance the hydrogens and oxygens.
- Tue Mar 05, 2019 1:59 pm
- Forum: Balancing Redox Reactions
- Topic: Adding H+ and H2O
- Replies: 13
- Views: 2952
Re: Adding H+ and H2O
Both steps are needed to balance the reaction.
- Tue Mar 05, 2019 1:55 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: K
- Replies: 5
- Views: 529
Re: K
K = 0 ; delta G = 0
K < 1 ; delta G > 0
K > 1 ; delta G < 0
K < 1 ; delta G > 0
K > 1 ; delta G < 0
- Mon Feb 11, 2019 9:28 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!
- Replies: 49
- Views: 11811
Re: Lyndon's HOTDOG MIDTERM REVIEW SESSION!! FINALLY!
I will not be able to make the review session tonight. Can someone post the answers given?
- Thu Dec 06, 2018 6:34 pm
- Forum: Einstein Equation
- Topic: Numbers to memorize [ENDORSED]
- Replies: 37
- Views: 4258
Re: Numbers to memorize [ENDORSED]
Soyoung Park 1H wrote:Do we have to memorize numbers such as c=3.00x10^8 m/s and planck's constant (h=6.63x10^-34Js) for the test?
No you do not we are given a constants and equations sheet. However it may be helpful to memorize them to some extent so you can do problems faster.
- Thu Dec 06, 2018 6:33 pm
- Forum: Einstein Equation
- Topic: de brogile equation
- Replies: 6
- Views: 1234
Re: de brogile equation
danielruiz1G wrote:in the de Broglie equation why does it state that any moving "particle" , when the examples talk about cars. can any moving object talk have a wavelength?
Yes any moving object has wavelength, but with large objects such as cars the wavelength is irrelevant.
- Thu Dec 06, 2018 6:31 pm
- Forum: Einstein Equation
- Topic: E=hv [ENDORSED]
- Replies: 52
- Views: 18580
Re: E=hv [ENDORSED]
Chase Yonamine 1K wrote:In the equation, E=hv, does E represent the energy of the photon or does it represent the energy required to remove an electron?
e represents the energy of a photon. The works function represents the energy required to remove an electron.
- Thu Dec 06, 2018 6:30 pm
- Forum: Photoelectric Effect
- Topic: Kinetic energy
- Replies: 11
- Views: 3343
Re: Kinetic energy
Madeline Lequang 1G wrote:Does the formula (1/2)mv^2 only apply to kinetic energy? or can it be used for other types of energy?
It only applies to kinetic energy.
- Thu Dec 06, 2018 6:29 pm
- Forum: Properties of Light
- Topic: Speed of light
- Replies: 13
- Views: 3902
Re: Speed of light
When doing calculations, should we use 2.99792 × 10 8 m.s -1 or 3.00 × 10 8 m.s -1 for the speed of light? I used the 3.00 × 10 8 m.s -1 on the midterm and got an answer that was two hundredths off and got it marked wrong, so what should be the accurate number to use? Look at the sig figs in the pr...
- Thu Dec 06, 2018 6:27 pm
- Forum: Trends in The Periodic Table
- Topic: Higher Electron Affinity Nitrogen or Carbon
- Replies: 4
- Views: 1125
Re: Higher Electron Affinity Nitrogen or Carbon
Sarah Bui 4I wrote:Hi! I was just wondering which element has a higher electron affinity nitrogen or carbon and why? I think this is one of the exceptions and I am not sure.
Carbon has a greater affinity for electrons than nitrogen because of its half filled p subshell which makes it more stable than Nitrogen.
- Thu Dec 06, 2018 6:25 pm
- Forum: Balancing Chemical Reactions
- Topic: Why do we balance chemical equations?
- Replies: 13
- Views: 8516
Re: Why do we balance chemical equations?
Madelyn Cearlock wrote:For the question that asks why do we balance chemical equations, what was the exact answer that was desired? Thank you!
Because of the law of conservation of mass.
- Thu Dec 06, 2018 6:25 pm
- Forum: Balancing Chemical Reactions
- Topic: Combustion Equation
- Replies: 21
- Views: 2860
Re: Combustion Equation
chrisavalos- 1K wrote:What is the rule for a combustion equation? Do they always produce Carbon Dioxide and Water? I have just never been sure of this. Thank You.
Yes, combustion reactions will always produce CO2 and H2O.
- Thu Dec 06, 2018 6:24 pm
- Forum: Significant Figures
- Topic: When to round the answers to significant figures
- Replies: 11
- Views: 2714
Re: When to round the answers to significant figures
Do we round the answer in every step of the calculation, or do we just round the final answer to the number of significant figures? Because when I round the answer in every step, my final answers are often different from those given by the textbook. It is best to only round your answers at the very...
- Thu Dec 06, 2018 6:23 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Molar Mass
- Replies: 8
- Views: 1325
Re: Molar Mass
Lily Smith 4C wrote:Where do you find the mass of an atom on the periodic table?
It is listed under the element in their box on the periodic table.
- Thu Dec 06, 2018 6:21 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge
- Replies: 8
- Views: 3539
Re: Formal Charge
Number of valence electrons - (number of lone electrons + number of lines drawn)
- Thu Dec 06, 2018 6:19 pm
- Forum: Electronegativity
- Topic: Electronegativity
- Replies: 4
- Views: 915
Re: Electronegativity
chrisdinkel_1K wrote:do we have to determine relative Electronegativites by periodic trends or is it given?
You have to use periodic trends to determine relative electronegativities.
- Thu Dec 06, 2018 6:16 pm
- Forum: Lewis Structures
- Topic: Elements that break the octet rule
- Replies: 6
- Views: 856
Re: Elements that break the octet rule
So I know that Br, I, and P can break the octet rule in lewis structures, but I read that there are other elements that can do this too, like Cl occasionally. Which elements are we required to know that break the octet rule for this class? It is better to think of it conceptually that if an element...
- Thu Dec 06, 2018 6:14 pm
- Forum: Trends in The Periodic Table
- Topic: Bond Lenghts
- Replies: 7
- Views: 933
Re: Bond Lenghts
How can you tell which molecules have a greater bond length without having its Lewis structure? I know when you have two ions you look for polarizability but what about when you have multiple elements involved? You would need to draw the Lewis structure to determine which molecules have a greater b...
- Thu Dec 06, 2018 6:12 pm
- Forum: Properties of Electrons
- Topic: Electron Configuration
- Replies: 9
- Views: 1188
Re: Electron Configuration
melissa_dis4F wrote:For the electron configuration of Pd I get [Kr]4d^8 5s^2 but it is [Kr] 4d^10. My question is do we change it to [Kr] 4d^10 because we should fill in the entire d orbital before continuing to the 5s orbital? Is this always?
Yes this is always. It is one of the exceptions to the octet rule.
- Thu Dec 06, 2018 6:11 pm
- Forum: Photoelectric Effect
- Topic: Work Function
- Replies: 14
- Views: 2274
Re: Work Function
Melissa Villanueva 3D wrote:How would we solve for the work function? Like what type of information would be given to use in order to find the work function and how would we use the given. Thanks!
You rearrange the formula as you would with an algebraic equation and plug in what is given to solve for the work function.
- Thu Dec 06, 2018 6:08 pm
- Forum: Electronegativity
- Topic: Trend of Electronegativity
- Replies: 18
- Views: 4265
Re: Trend of Electronegativity
chrisavalos- 1K wrote:I was wondering what the trend for electronegativity was, is it the same as ionization energy?
Yes, the trend for electronegativity is the same as the trend for ionization energy.
- Thu Dec 06, 2018 6:07 pm
- Forum: Octet Exceptions
- Topic: Exceptions
- Replies: 10
- Views: 1394
Re: Exceptions
jane_ni_3b wrote:How should we know which ones are exceptions?
The most common exceptions we deal with are found in the 3rd period because of an unfilled d-orbital.
- Thu Dec 06, 2018 6:05 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: AXE formula
- Replies: 32
- Views: 12318
Re: AXE formula
Arlene Linares 3A wrote:How do we figure out the AXE formula? I am still having trouble with this.
A is the central atom. X is the number of atoms bonded to the central atom. E is the number of lone pairs on the central atom.
- Thu Dec 06, 2018 6:03 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: AXE formula
- Replies: 32
- Views: 12318
Re: AXE formula
danielruiz1G wrote:is it possible to determine the shape of a molecule if you're only given the AXE formula, if so how do you do it?
Yes because the AXE formula tells you the regions of electron density which is all you need to determine the shape.
- Thu Dec 06, 2018 6:02 pm
- Forum: Hybridization
- Topic: hybridization
- Replies: 13
- Views: 1846
Re: hybridization
KarlaArevalo4D wrote:Does anyone have an easy way to find the hybridization of the central atom they are able to share? Much appreciated.
The easiest way is to consider the number of regions with electron density. This includes lone pairs.
- Thu Dec 06, 2018 6:00 pm
- Forum: Hybridization
- Topic: pi vs sigma
- Replies: 12
- Views: 1235
Re: pi vs sigma
Arshia Ramesh 1G wrote:i read on one of the reviews that a pi bond is weaker than a sigma bond but why is that?
It is because a pi bond does not allow for rotation and would break while a sigma bond does allow for rotation.
- Thu Dec 06, 2018 5:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Square Planar
- Replies: 12
- Views: 2058
Re: Square Planar
Phoebe Chen 4I wrote:Are the bond angles in square planar less than or equal to 90?
They are equal to 90.
- Thu Dec 06, 2018 5:57 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: AX3E
- Replies: 18
- Views: 3307
Re: AX3E
kevinav wrote:What would be the molecular shape for the general formula AX3E
The molecule would have a trigonal pyramidal molecular shape.
- Thu Dec 06, 2018 5:55 pm
- Forum: Hybridization
- Topic: lone pairs
- Replies: 20
- Views: 2176
Re: lone pairs
Moryel Yashar 1J wrote:Are lone pairs taken into consideration when determining the hybridization of a central atom?
Yes lone pairs are taken into consideration because they are still areas of electron density.
- Thu Dec 06, 2018 5:54 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Determining Lewis Acids and Bases
- Replies: 1
- Views: 198
Determining Lewis Acids and Bases
How do I determine which compound is a Lewis Acid and which compound is a Lewis base?
- Fri Nov 02, 2018 7:33 pm
- Forum: Lewis Structures
- Topic: How to decide central atom?
- Replies: 6
- Views: 970
Re: How to decide central atom?
Nicholas Le 3A wrote:Is the central atom in the Lewis structures based off of which atom has the lowest electronegativity or which atom has the lowest ionization energy?
It is based off of lowest ionization energy.
- Fri Nov 02, 2018 7:31 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Scantron
- Replies: 6
- Views: 607
Re: Scantron
904837647 wrote:So the midterm should be formatted just like the test?
Yes, the midterm should be formatted similarly to the tests.
- Fri Nov 02, 2018 7:29 pm
- Forum: Student Social/Study Group
- Topic: Midterm
- Replies: 15
- Views: 1582
Re: Midterm
Do we know how many questions from each section will be in the test? Like how many from the fundamentals, quantum, and chemical bonds? I know there’s 8 but how is it going to be divided? My TA said that the amount of questions from each section would correlate to the amount of time we spent on said...
- Fri Oct 26, 2018 2:13 pm
- Forum: Properties of Light
- Topic: Electromagnetic Spectrum
- Replies: 5
- Views: 601
Re: Electromagnetic Spectrum
You do not need to fully memorize the spectrum but it will definitely be helpful to be familiar with it for the course.
- Fri Oct 26, 2018 2:10 pm
- Forum: DeBroglie Equation
- Topic: Measurable wavelength properties
- Replies: 5
- Views: 585
Re: Measurable wavelength properties
The car was too large to have "measurable wavelike properties".
- Fri Oct 26, 2018 2:07 pm
- Forum: Einstein Equation
- Topic: Units
- Replies: 6
- Views: 959
Re: Units
The test required students to know correct units as well as significant figures.
- Fri Oct 05, 2018 9:23 pm
- Forum: SI Units, Unit Conversions
- Topic: How does grading for discussion posts work?
- Replies: 80
- Views: 9319
Re: How does grading for discussion posts work?
Does anyone actually know when the discussion posts are due?
- Fri Oct 05, 2018 9:22 pm
- Forum: Balancing Chemical Reactions
- Topic: States of Matter
- Replies: 11
- Views: 1063
Re: States of Matter
Does anyone know if we need to write the different states of matter in each equation?
- Fri Oct 05, 2018 9:21 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Number of questions on test one [ENDORSED]
- Replies: 39
- Views: 21817
Re: Number of questions on test one [ENDORSED]
Dr. Lavelle hasn't said how many questions the test will be nor how it will be graded.