Search found 49 matches
- Wed Mar 14, 2018 1:11 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: k and Ea
- Replies: 4
- Views: 2041
Re: k and Ea
k is small because if the activation energy is high, it will be harder for the reaction to produce products
- Wed Mar 14, 2018 1:10 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Adsorption
- Replies: 4
- Views: 679
Re: Adsorption
During lecture, Lavelle talked about how sponges absorb water and catalysts are adsorbing a reactant, meaning the reactant sits on top of the catalyst. There is a slight adhesion when a catalyst adsorbs a reactant. This allows the reactant to detach from the catalyst as the reaction proceeds. Once t...
- Wed Mar 14, 2018 1:02 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Catalyst
- Replies: 2
- Views: 457
Re: Catalyst
Catalysts speed up reactions (k) by lowering activation energy. They also provide a new pathway for reactions, and these new pathways have lower activation energy.
- Mon Mar 05, 2018 2:49 pm
- Forum: Second Order Reactions
- Topic: Determining order of a reaction
- Replies: 2
- Views: 752
Re: Determining order of a reaction
You can just use the coefficients only when using the reaction mechanisms. You are looking at the individual steps then the overall equation. The order of each of reaction determines the coefficients
- Mon Mar 05, 2018 2:46 pm
- Forum: Second Order Reactions
- Topic: Order reactions
- Replies: 6
- Views: 1109
Re: Order reactions
Order reactions are determined by looking how the rate changes in relation to the concentration. Then you can use the proper equation and apply it to the problem.
- Mon Mar 05, 2018 2:44 pm
- Forum: Second Order Reactions
- Topic: molecularity
- Replies: 6
- Views: 938
Re: molecularity
Yes you do.
A -> P unimolecular
A+B -> bimolecular
A+A -> bimolecular
A -> P unimolecular
A+B -> bimolecular
A+A -> bimolecular
- Mon Mar 05, 2018 2:22 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Which Step is Slower?
- Replies: 8
- Views: 932
Re: Which Step is Slower?
You can determine the slowest step by the determination rate or the part of the graph that requires the most activation energy.
- Mon Mar 05, 2018 2:20 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: slowest step determines rate of overall reaction
- Replies: 3
- Views: 557
Re: slowest step determines rate of overall reaction
The slowest step determines the rate of the overall reaction because all the other reactions following is going as fast as the slowest step. Which means that the slowest step controls the overall rate of the overall reaction.
- Mon Mar 05, 2018 2:15 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Friday Lecture
- Replies: 5
- Views: 638
Re: Friday Lecture
Correct, CO2 is a zero order so it doesn't affect the determination rate or the slow step.
- Thu Feb 22, 2018 2:45 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Nernst Equation
- Replies: 6
- Views: 954
Re: Nernst Equation
nr is the molar coefficient of the Nernst Equation. It is basically the number of moles of electrons transferred.
- Thu Feb 22, 2018 2:42 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: redox
- Replies: 7
- Views: 1226
Re: redox
LEO: loss (of) electrons OXIDIZE
Reduction is gaining electrons.
Reduction is gaining electrons.
- Thu Feb 22, 2018 2:39 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Cell Potential
- Replies: 9
- Views: 3240
Re: Cell Potential
Both of these equations are the same. constants R, T, F = to .05916
- Mon Feb 12, 2018 4:15 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Using Nernst Equation
- Replies: 2
- Views: 523
Re: Using Nernst Equation
The nernst equation is describing the cell potential, which the direction where the electron goes, and how it depends on concentration under different conditions.
- Mon Feb 12, 2018 4:10 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: system vs surroundings
- Replies: 6
- Views: 970
Re: system vs surroundings
If the surroundings is everything except the system, then the system is the reaction and the beaker and everything else is the surrounding.
- Mon Feb 12, 2018 4:05 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Delta G= Wmax
- Replies: 8
- Views: 2488
Re: Delta G= Wmax
DeltaG is the maximum amount of work a system can do at a given temperature and pressure, while WMAX is the maximum amount of work a system can do. Therefore, you can set them equal to each other.
- Thu Feb 08, 2018 4:16 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: deltaS question
- Replies: 7
- Views: 938
Re: deltaS question
5/2 and 3/2 are used for specific heat capacities of ideal gases. For the problems in the book, you should only use Cp when dealing with ideal gases, if not, then use R for non-ideal gases
- Thu Feb 08, 2018 4:10 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: formula for standard entropy
- Replies: 5
- Views: 788
Re: formula for standard entropy
Yes, the formula for standard entropy is the same as the other standard formations we did last chapter.
- Thu Feb 08, 2018 4:08 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Kelvin
- Replies: 4
- Views: 559
Re: Kelvin
Look at the signs throughout the problems, but in most cases, you should write in kelvins just to keep it constant throughout the problem.
- Thu Feb 08, 2018 4:05 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Delta G
- Replies: 3
- Views: 461
Re: Delta G
DeltaG: is the change in free energy under a different temperatures and pressure conditions.
DeltaGnaut: is standardized conditions for pressure (1 ATM) and temperture (25 degree celcius/298 Kelvins)
DeltaGnaut: is standardized conditions for pressure (1 ATM) and temperture (25 degree celcius/298 Kelvins)
- Thu Feb 08, 2018 4:03 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Entropy Concept
- Replies: 2
- Views: 394
Re: Entropy Concept
Endothermic reactions/processes are spontaneous because this kind of process absorbs heat which increases the total entropy of a system.
- Thu Feb 01, 2018 12:01 am
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Entropy vs. Standard Entropy
- Replies: 4
- Views: 539
Re: Entropy vs. Standard Entropy
the word standard used in this sense represents that every reactants and products are in their purest forms. Only one mole is produced.
- Wed Jan 31, 2018 11:57 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: what exactly is free energy?
- Replies: 5
- Views: 666
Re: what exactly is free energy?
Gibbs free energy is basically the free energy in a process available to do work. An important relationship to consider is ΔG = ΔH - TΔS, which, if you know the signs of the unknowns, you can determine the sign of ΔG and hence predict if a reaction is favorable or not.
- Wed Jan 31, 2018 11:51 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Internal Energy in a Vacuum [ENDORSED]
- Replies: 5
- Views: 976
Re: Internal Energy in a Vacuum [ENDORSED]
since work is defined as w = -P DELTA V, and because it is in a vacuum there is no opposing force that is occurring which results in no work.
- Fri Jan 19, 2018 11:15 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Work Equation
- Replies: 4
- Views: 532
Re: Work Equation
energy is being released which means there's a negative sign
- Fri Jan 19, 2018 11:10 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: 8.1 part c [ENDORSED]
- Replies: 8
- Views: 1167
Re: 8.1 part c [ENDORSED]
it is an isolated system which means that there's no interactions with the environment and heat is not given off.
- Fri Jan 19, 2018 10:47 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Calorimeter
- Replies: 10
- Views: 1075
Re: Calorimeter
calorimeter is used to measure specific heat capacity. In the example of the coffee cup calorimeter, heat is measured under conditions of constant pressure and in the bomb calorimeter, heat is measured under conditions of constant pressure. Use Q=m x C x Delta T
- Sun Jan 14, 2018 5:34 pm
- Forum: Phase Changes & Related Calculations
- Topic: qv vs qp
- Replies: 4
- Views: 2226
Re: qv vs qp
Qv is constant volume, Qp is constant pressure. Lavelle used Qv in the example of the bomb calorimeter and Qp in the coffee cup calorimeter.
Qv: heat absorbed or released at constant volume. Qp: heat absorbed or released at constant pressure and gives enthalpy values.
Qv: heat absorbed or released at constant volume. Qp: heat absorbed or released at constant pressure and gives enthalpy values.
- Sun Jan 14, 2018 5:30 pm
- Forum: Phase Changes & Related Calculations
- Topic: Methods of Enthalpy
- Replies: 8
- Views: 877
Re: Methods of Enthalpy
It honestly depends on the question because there are 3 methods of enthalpy. 1. Hess' Method 2. Bond Enthalpies 3. Standard Enthalpies of Formation
- Sun Jan 14, 2018 5:25 pm
- Forum: Phase Changes & Related Calculations
- Topic: Endo and Exothermic Ways to Remember
- Replies: 28
- Views: 11662
Re: Endo and Exothermic Ways to Remember
The prefixes of the words determine what the meaning of them. "En"dothermic sounds like "In"dothermic, which means that heat is being absorbed and "Ex"othermic means exit, so heat is being released.
- Sat Dec 09, 2017 5:21 pm
- Forum: Bronsted Acids & Bases
- Topic: % dissociation
- Replies: 3
- Views: 605
Re: % dissociation
%dissociation is calculated by taking the conjugate base/acid and dividing it by the initial condition then multiplying it by 100.
- Fri Dec 08, 2017 2:16 am
- Forum: Bronsted Acids & Bases
- Topic: identifying based on structure
- Replies: 4
- Views: 551
Re: identifying based on structure
For this question, it was asking about lewis acids and lewis bases. Lewis acids accept electrons and lewis bases donate electrons. Ag+ can accept electrons which makes it an acid, while F- can donate an electron which makes it a base.
- Fri Dec 08, 2017 2:08 am
- Forum: Identifying Acidic & Basic Salts
- Topic: Final: Strong/ Weak Acids/Bases
- Replies: 11
- Views: 1532
Re: Final: Strong/ Weak Acids/Bases
Salts are not on the final test, but you should look over them in the course reader!
- Thu Nov 30, 2017 11:57 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Quotient
- Replies: 12
- Views: 974
Re: Quotient
Q is the quotient which is the for when the reaction is given with whatever initial values are given. K is the equilibrium quotient which is the ratio of the concentration and partial pressure of the reactants and products
- Thu Nov 30, 2017 11:54 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 11.43
- Replies: 1
- Views: 485
Re: 11.43
Yes, the problem involves the ICE box. 2NO(g) <>N2(g) + O2(g)
(N2)(O2)/(NO^2) = (x)(x)/(1)^2 = x^2/(1-2x)^2
The answer is C.
2NO N2 O2
I 1.0 0 0
C -2x x x
E 1-2x x x
(N2)(O2)/(NO^2) = (x)(x)/(1)^2 = x^2/(1-2x)^2
The answer is C.
2NO N2 O2
I 1.0 0 0
C -2x x x
E 1-2x x x
- Fri Nov 24, 2017 5:56 pm
- Forum: Biological Examples
- Topic: Coordination Compound
- Replies: 2
- Views: 511
Re: Coordination Compound
A coordination compound is a neutrally charged compound and it usually consists of a transition metal connected by sets of ligands. You can determine the coordination number because of how many bonds there are on the compound. These do not relate to hybridization.
- Fri Nov 24, 2017 5:35 pm
- Forum: Naming
- Topic: HW 17.31 b
- Replies: 4
- Views: 583
Re: HW 17.31 b
The answer that is provided through solutions manual is correct because Cobalt has an oxidation number of 3+ and Sulfate has an oxidation number of 2-, which means the overall oxidation number is 1. So it is [Co(NH3)5(SO4)]Cl
- Fri Nov 17, 2017 11:19 pm
- Forum: Hybridization
- Topic: sigma/pi bond
- Replies: 4
- Views: 728
Re: sigma/pi bond
Yes that is correct, as you said with a double bond, the first bond is a sigma bond and the second one is pi bond. For a triple bond, the first bond is a sigma bond and the second and the third bonds are pi bonds
- Fri Nov 17, 2017 11:07 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Cis- vs. Trans-
- Replies: 4
- Views: 746
Re: Cis- vs. Trans-
Cis and Trans represents the geometric isomerism. If 2 groups are on the same side, then it is a cis and if the other groups are on opposite side then it is a trans
- Tue Nov 14, 2017 5:49 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Calculating Formal Charge
- Replies: 4
- Views: 797
Re: Calculating Formal Charge
Subtract the valence electrons of an elements by the bonds and electrons that are around it. Bonds are represented as 1 electron.
- Sun Nov 05, 2017 5:40 pm
- Forum: Resonance Structures
- Topic: Resonance Structures
- Replies: 3
- Views: 647
Re: Resonance Structures
The most important idea here is draw out all the possible lewis structures to determine the resonance. A lot of the times, the double bond or triple bond can occur almost anywhere, but in some specific elements a double bond can only occur in a specific spot. So beware and be careful when drawing ou...
- Sun Nov 05, 2017 5:37 pm
- Forum: Lewis Structures
- Topic: electron configuration
- Replies: 6
- Views: 788
Re: electron configuration
The electron configuration is written [Ar]3d104s2 because the it goes in order increasing energy and it is the way that Dr. Lavelle wants it to be written.
- Thu Oct 26, 2017 10:49 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Px, Py, Pz
- Replies: 10
- Views: 1319
Re: Px, Py, Pz
On Wednesday, during the lecture, Lavelle said that you can write it both ways. He prefers that you write in the notation Px, Py, Pz because it is much more specific and it clears up all kinds of confusion when determining paired/parallel electrons.
- Fri Oct 20, 2017 12:05 am
- Forum: Photoelectric Effect
- Topic: Energy of Photon [ENDORSED]
- Replies: 9
- Views: 2466
Re: Energy of Photon [ENDORSED]
When the energy is equal to each other, the energy is still enough to emit a photon, but the kinetic energy would be zero.
- Fri Oct 20, 2017 12:01 am
- Forum: Properties of Electrons
- Topic: Rydberg's formula
- Replies: 6
- Views: 1079
Re: Rydberg's formula
Rydberg's formula is used for finding the wavelength, energy, or frequency of an electron that is moving from one level to the next. Usually you the initial and final levels will be given, but in some other cases, the question will ask for the initial and the final. So that's when you used the formu...
- Thu Oct 19, 2017 11:57 pm
- Forum: DeBroglie Equation
- Topic: λ=c/v VS. λ=h/mv
- Replies: 9
- Views: 13129
Re: λ=c/v VS. λ=h/mv
λ=c/v : this equation means λ (wavelength) is equal to c (speed of light) divided by v (frequency). c will always be 3.00 x 10^8 m/s. λ=h/mv : this equations means that λ (wavelength) is equal to h (Plank's constant) divided by m (momentum) * v (velocity). The biggest difference between the that λ=c...
- Sat Oct 14, 2017 7:16 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Question about Balmer Series [ENDORSED]
- Replies: 2
- Views: 1789
Re: Question about Balmer Series [ENDORSED]
The Balmer series begins at n=2, if the electron is going down from n=2 to n=1, it would be considered the Lyman series.
- Sat Oct 14, 2017 7:11 pm
- Forum: Properties of Light
- Topic: Balmer vs Lyman Series [ENDORSED]
- Replies: 3
- Views: 511
Re: Balmer vs Lyman Series [ENDORSED]
Balmer Series (656.3 nm, 486.1 nm, 434.8 nm, 410.2 nm) is connected to visible light section of the spectrum, while Lyman Series (121.6 nm, 102.6 nm, 97.3 nm) is connected to the ultraviolet section of the spectrum. The Lyman series is indicated by when the electron is excited from the ground state ...
- Fri Oct 06, 2017 4:56 pm
- Forum: Empirical & Molecular Formulas
- Topic: F.13
- Replies: 6
- Views: 4347
Re: F.13
you are on the right track by subtracting 27.8 grams by 4.14 grams of P. That will give you 23.66 grams of Cl, so all you have to do is divide each of the element by it's mass. P: 4.14/30.974 = .1336604894 Cl: 23.16/75.45 = .6533145275 Next, you would divide the smallest amount into each of them, so...
- Fri Oct 06, 2017 4:36 pm
- Forum: Significant Figures
- Topic: 3 Sig Figs 1795.507? [ENDORSED]
- Replies: 5
- Views: 1051
Re: 3 Sig Figs 1795.507? [ENDORSED]
You should round up to 1800, then convert it into scientific notation. For 3 sig figs, the answer should be 1.80 x 10^3