Search found 95 matches
- Wed Mar 11, 2020 4:58 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Previous Final Questions (Slide 5)
- Replies: 1
- Views: 208
Previous Final Questions (Slide 5)
In the slides of the problems from previous exam questions that Lavelle sent out today, for slide 5, does anyone know why the K expression has a 2x in the numerator (products)?. The balanced chemical equation has all stoic coefficients of 1 so I don't know where that comes from.
- Tue Mar 10, 2020 11:48 pm
- Forum: General Rate Laws
- Topic: Pseudo Rate Law
- Replies: 1
- Views: 198
Re: Pseudo Rate Law
When given the overall rate law of a multi step reaction, sometimes one singular step of the reaction does not have all of the elements that make up the rate law. For example, if you are given the rate law: k[A]^2[C] and the reaction steps: 1. A+A—>D and 2. D+C—>B. You can see that the rate law for ...
- Tue Mar 10, 2020 11:18 pm
- Forum: Environment, Ozone, CFCs
- Topic: stoichiometric coefficients
- Replies: 19
- Views: 1528
Re: stoichiometric coefficients
The reason it was in fraction form was because the first step of the reaction wanted to be written to get exactly one mole of product just to make it simpler. Therefore, to make this happen, there needed to be 1/2(O2) as a reactant. If you had started with 1 mole O2 then you would end up with 2 mole...
- Tue Mar 10, 2020 11:13 pm
- Forum: *Enzyme Kinetics
- Topic: kprime and k1
- Replies: 2
- Views: 638
Re: kprime and k1
Yes, they are different. The forward reaction is k and the reverse is k’. The equilibrium constant, K, is calculated by k/k’, which also corresponds to [reactants]/[products].
- Tue Mar 10, 2020 11:11 pm
- Forum: *Enzyme Kinetics
- Topic: Collision model
- Replies: 2
- Views: 266
Re: Collision model
It helps us know how many collisions occur with sufficient energy to cause a reaction to occur. The higher the temperature, the more collisions with sufficient energy.
- Tue Mar 10, 2020 11:09 pm
- Forum: *Enzyme Kinetics
- Topic: How do you tell if something is a catalyst vs an intermediate?
- Replies: 16
- Views: 6067
Re: How do you tell if something is a catalyst vs an intermediate?
An intermediate is formed and then used up. A catalyst is what is needed to get a reaction going (so kind of like a reactant), and then it is eventually reproduced/shows up in another step of the reaction. It is never “consumed” (not the greatest word to use but...) without reappearing.
- Sun Mar 08, 2020 8:16 pm
- Forum: Second Order Reactions
- Topic: Final Exam Equations
- Replies: 10
- Views: 800
Re: Final Exam Equations
yes, they are given but they are not labeled, so you will have to remember which equation corresponds to which order and also what they are used for.
- Sun Mar 08, 2020 8:11 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Energy Barrier
- Replies: 4
- Views: 316
Re: Energy Barrier
I believe it just shows the difference between the energy barrier for the forward reaction versus the reverse reaction. If the slow step is the determining factor for the rate of the reaction, then I guess you could say that it represents the slow step?
- Sun Mar 08, 2020 7:59 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: collision theory
- Replies: 2
- Views: 235
Re: collision theory
I believe Lavelle already went over this in last week's lecture when explaining the variable A which takes into account the number of collisions with correct orientation.
- Sun Mar 08, 2020 7:54 pm
- Forum: General Rate Laws
- Topic: Graphs of rate laws
- Replies: 8
- Views: 1109
Re: Graphs of rate laws
Depending on the different rate laws for the different ordered reactions, plotting the corresponding term on the y-axis against time will yield a straight line instead of a curve. For example, if given a graph with the y-axis as 1/ln[A] plotted against time, and the graph is a straight line, then yo...
- Sun Mar 08, 2020 7:49 pm
- Forum: General Rate Laws
- Topic: Rate limiting step
- Replies: 12
- Views: 879
Re: Rate limiting step
The limiting step is the slowest step, and it is also the step that defines the overall rate of the reaction.
- Sun Mar 01, 2020 9:56 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n value
- Replies: 4
- Views: 403
Re: n value
I’m not sure what you mean by halving or doubling the reactions, but the reason you manipulate and balance half reactions is so that you have equivalent number of electrons being taken from the oxidized substance as you are adding to the reduced substance. This number would be the same in both half ...
- Sun Mar 01, 2020 9:46 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Standard Cell Potential for Oxidation Half-Reactions
- Replies: 3
- Views: 230
Re: Standard Cell Potential for Oxidation Half-Reactions
Yes. Since all the half reaction standard potentials are given as reduction half reactions, you have to flip the equation of the substance at the anode (getting oxidized) which flips the sign of the E value. An easy way to know which one to flip is by choosing the one that would result in a more pos...
- Sun Mar 01, 2020 9:44 pm
- Forum: Balancing Redox Reactions
- Topic: moles of electrons transferred
- Replies: 4
- Views: 404
Re: moles of electrons transferred
You look at the change in charge of the substance. If something is being reduced from a 4+ charge to a 2+ charge, you know that the initial substance must have received 2 electrons (4+)+(2-)=(2+).
- Sun Mar 01, 2020 9:37 pm
- Forum: Balancing Redox Reactions
- Topic: Anode and Cathode
- Replies: 9
- Views: 598
Re: Anode and Cathode
Electrons are always flowing from the anode to the cathode. You can tell which substances are at the anode by determining which substance is losing electrons. The opposite goes for the cathode. In a cell diagram (written), the substances on the left of the double lines are the ones at the anode.
- Sun Mar 01, 2020 12:47 pm
- Forum: Balancing Redox Reactions
- Topic: 6N.1
- Replies: 2
- Views: 221
6N.1
In problem 6N.1 part b, why does the reduction of In 2+ —> In 3+ require 2 electrons instead of one?
- Sun Feb 23, 2020 7:21 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cell Notation
- Replies: 3
- Views: 330
Re: Galvanic Cell Notation
You would have to add a solid electrode (inert conductor) and the most common form of this is platinum or graphite.
- Sun Feb 23, 2020 6:40 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrochemical series diagram
- Replies: 2
- Views: 199
Re: Electrochemical series diagram
This table is used when trying to figure out which part of a reaction is doing the oxidizing or reducing. Whichever half reaction can reduce H+ is the half reaction that you should choose as the oxidation half of the reaction.
- Sun Feb 23, 2020 6:34 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Platinum
- Replies: 4
- Views: 280
Re: Platinum
The left side of this diagram already has Copper, so you do not need another electrode on that side. Platinum is added to the right side in order to serve as the electrode that can receive the electrons coming from the copper getting oxidized.
- Sun Feb 23, 2020 6:32 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Standard Cell Potential
- Replies: 4
- Views: 344
Re: Standard Cell Potential
The half reactions are given as reductions, and since a reaction requires oxidation and reduction, whichever half has the oxidation occurring would have a flipped equation and sign for the cell potential. If you were to switch the sides of the diagram, then both half reactions would change signs and...
- Sun Feb 23, 2020 6:27 pm
- Forum: Balancing Redox Reactions
- Topic: Flow of electrons
- Replies: 11
- Views: 824
Re: Flow of electrons
Electrons always go from the anode to the cathode because oxidation, or removal of electron, is always and only happening at the anode.
- Fri Feb 14, 2020 4:31 pm
- Forum: Phase Changes & Related Calculations
- Topic: Expansion Work
- Replies: 6
- Views: 478
Re: Expansion Work
Expansion work only corresponds to a change in volume. If there is no change in volume, there is no expansion work (or any work done at all if you are talking about an irreversible reaction).
- Fri Feb 14, 2020 4:28 pm
- Forum: Phase Changes & Related Calculations
- Topic: Delta H Fusion
- Replies: 9
- Views: 722
Re: Delta H Fusion
You need to separate the processes of the energy required to melt the ice, and the energy required to raise the temperature of the ice that has melted (or you could think of it as the energy coming out of the surrounding in order to change the temperature of the water that came from the melted ice a...
- Fri Feb 14, 2020 4:25 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs Free energy concept
- Replies: 16
- Views: 882
Re: Gibbs Free energy concept
Free energy is the energy that is available to do work, and Delta G is useful for telling us if the current state of a process is spontaneous (-delta G and system will do work) or not spontaneous (wont do work).
- Fri Feb 14, 2020 4:23 pm
- Forum: Calculating Work of Expansion
- Topic: Determining Expansion Work
- Replies: 4
- Views: 640
Re: Determining Expansion Work
By comparing the moles of gas on the reactant and products sides of the balanced equation, you can tell if the system has done expansion work. If moles of R > moles of P, the system has compressed. If moles R < moles of P, the system has expanded. This is all assuming that this is an open system and...
- Fri Feb 14, 2020 4:18 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: higher molar entropies
- Replies: 2
- Views: 242
Re: higher molar entropies
Monoatomic gases have the potential to occupy more positions than a diatomic gas, and this would cause the degeneracy term for a monoatomic gas to be higher than a diatomic gas. Given the relationship between degeneracy and entropy, this would lead to a higher entropy for a monoatomic gas.
- Fri Feb 07, 2020 3:34 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Change in internal energy
- Replies: 3
- Views: 181
Re: Change in internal energy
Change in internal energy = 0 when there is no change in temperature (this is called isothermal). Delta U is = q when no work is being done on or by the system (constant volume). When a system is irreversible, external pressure is not equal to internal pressure. All real processes are irreversible (...
- Fri Feb 07, 2020 3:21 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: Boltzman Constant
- Replies: 4
- Views: 172
Re: Boltzman Constant
It’s J/K which is similar to R which is J/K.mol, except the Boltzmann constant is per particle not mole
- Fri Feb 07, 2020 3:17 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Delta in enthalpy and not entropy
- Replies: 6
- Views: 195
Re: Delta in enthalpy and not entropy
There is also a delta for the entropy term because entropy is a state function.
- Fri Feb 07, 2020 3:14 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: aq vs gas vs liquid
- Replies: 2
- Views: 129
Re: aq vs gas vs liquid
Gas>aqueous>liquids>solids because gases can occupy the most states while solids have one very defined volume or space that they occupy
- Fri Feb 07, 2020 3:08 pm
- Forum: Calculating Work of Expansion
- Topic: Isothermal
- Replies: 17
- Views: 819
Re: Isothermal
If the expansion of the gas is isothermal, then this means the temperature remains constant and delta U = 0 Could you explain why delta U would equal 0? I'm a little confused about the connection between temperature and delta U. Delta U = 0 because the temperature of the system is not changing, mea...
- Sun Feb 02, 2020 6:15 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Microstates
- Replies: 2
- Views: 148
Re: Microstates
Microstates describe all the different ways atoms can be arranged without a difference in energy.
- Sun Feb 02, 2020 6:09 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Delta U = Q
- Replies: 8
- Views: 222
Re: Delta U = Q
Work=0 when volume is not changing or when pressure is zero (vacuum).
- Sun Feb 02, 2020 6:00 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Pressure in an open beaker
- Replies: 12
- Views: 819
Re: Pressure in an open beaker
In an open beaker, the system is at constant pressure because there is no volume to contain any increase or decrease in pressure, and the pressure of the system will be the same as the atmosphere.
- Sun Feb 02, 2020 5:54 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Variables
- Replies: 3
- Views: 147
Re: Variables
Those are all correct. You will need to add S, which is entropy, and W, which is degeneracy. The equation sheet will be useful because if you understand the equations, then you will likely be able to deduce which term corresponds to which meaning.
- Sun Feb 02, 2020 5:52 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies
- Replies: 6
- Views: 405
Re: Bond Enthalpies
When bonds are formed, energy is released (an exothermic process), so the corresponding enthalpy term is negative. The opposite goes for breaking bonds.
- Sun Jan 26, 2020 3:43 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Lewis Structures Method 2
- Replies: 6
- Views: 183
Re: Lewis Structures Method 2
As long as you can figure out which bonds are broken and formed, then you do not need to draw out the Lewis structures and you can just refer to the table of bond enthalpy values.
- Sun Jan 26, 2020 3:41 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: heat rxn
- Replies: 2
- Views: 118
Re: heat rxn
You can find the bond enthalpies of the reactants and products involved in breakage/forming of bonds in the reaction and then add those enthalpies to find the total enthalpy of the reaction. You can also calculate (total enthalpy of products) - (total enthalpy of reactants) which will yield the tota...
- Sun Jan 26, 2020 3:23 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam v. liquid
- Replies: 7
- Views: 297
Re: Steam v. liquid
Since the enthalpy of the vapor phase is higher than the enthalpy for the liquid phase of water, steam contains more heat which is then released (exothermic reaction) when it condenses, causing a more severe burn than liquid water alone.
- Sun Jan 26, 2020 3:19 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: different methods
- Replies: 3
- Views: 242
Re: different methods
I would say its definitely dependent on the information given. Method 1: if they give you the reactions and their enthalpies, definitely use this. Method 2: If you don’t have the enthalpies but have the reactants, products, and the values of the enthalpies of bonds, use this method. Method 3: If giv...
- Sun Jan 26, 2020 3:09 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: adding enthalpy of phase changes
- Replies: 2
- Views: 129
Re: adding enthalpy of phase changes
Since different phases have different enthalpies, you have to take that into account when doing a calculation because the table of bond enthalpies that you use for calculations has everything in terms of the gas phase.
- Sun Jan 19, 2020 8:51 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Not including solids and liquids
- Replies: 7
- Views: 311
Re: Not including solids and liquids
Solids and liquids are not included in the equilibrium constant equation because they do not have concentrations. They have densities. Therefore, they are negated when calculating the K value.
- Thu Jan 16, 2020 5:29 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Protonation & Deprotonation
- Replies: 9
- Views: 384
Re: Protonation & Deprotonation
Protonation occurs when a hydrogen ion is added to a molecule, and deprotonation happens when a molecule loses a proton. Bases are often protonated and acids are usually deprotonated. You calculate % protonation by dividing the product species that has been protonated/deprotonated by its conjugate f...
- Thu Jan 16, 2020 5:01 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Endothermic and exothermic
- Replies: 5
- Views: 229
Re: Endothermic and exothermic
Breaking bonds usually requires energy (endothermic), and forming bonds usually releases energy (exothermic). Also, if a reaction is spontaneous it is usually exothermic.
- Thu Jan 16, 2020 4:58 pm
- Forum: Ideal Gases
- Topic: ICE Table
- Replies: 11
- Views: 852
Re: ICE Table
ICE tables are used when you need to find out the equilibrium concentrations of products or reactants when only given the initial concentration of one. You use the balanced chemical equation when calculating the change (represented by x times the stoichiometric coefficient) and then solve for x to f...
- Thu Jan 16, 2020 4:48 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Approximation
- Replies: 8
- Views: 346
Re: Approximation
If the K value is less than 10^-3, then the concentrations of products created are small enough in comparison to the original concentration of the reactant(s) that you can consider it insignificant enough to leave the “-x” term out of the reactants when calculating K.
- Thu Jan 09, 2020 6:17 pm
- Forum: Ideal Gases
- Topic: Solving for K (coefficients)
- Replies: 11
- Views: 602
Re: Solving for K (coefficients)
You raise the value the concentration of a certain reactant/product to their respective coefficients in the balanced chemical equation.
- Thu Jan 09, 2020 6:14 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Q vs K
- Replies: 7
- Views: 286
Re: Q vs K
Q is used to evaluate the concentration of reactants and products at any given point in a reaction. If Q = K, then the reaction is in equilibrium at that time. If Q>K, then that means there are more reactants present at that time than there would be if the reaction was in equilibrium. If Q<K, that m...
- Thu Jan 09, 2020 6:12 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G.11
- Replies: 4
- Views: 202
Re: 5G.11
You cannot include solids and liquids in an equilibrium equation because they do not have pressures or concentrations (they have densities).
- Thu Jan 09, 2020 6:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: solids and liquids
- Replies: 6
- Views: 231
Re: solids and liquids
Solids and liquids don’t have a concentration (they have density). Therefore it would not make sense to include them in an equilibrium expression.
- Thu Jan 09, 2020 6:09 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K pressure units
- Replies: 3
- Views: 211
Re: K pressure units
You should use numbers with the same units when you are doing calculations.
- Mon Dec 09, 2019 8:20 am
- Forum: Sigma & Pi Bonds
- Topic: Carbon's hybridization
- Replies: 3
- Views: 530
Re: Carbon's hybridization
Hybridization is an experimentally determined concept to explain why carbon can make four bonds. Since we know carbon can make four bonds, hybridization was developed as a model to explain how this happens. We invoke hybridization when we see that carbon forms 4 bonds.
- Mon Dec 09, 2019 8:11 am
- Forum: Dipole Moments
- Topic: CCl2H2
- Replies: 2
- Views: 657
Re: CCl2H2
If a tetrahedral shape had all the same bonds in the same plane then the dipole moments could cancel. However, because it is a three dimensional shape, as Lavelle said, the only way for the dipole moments to cancel is if the central atom is bound to four atoms of the same element.
- Mon Dec 09, 2019 8:08 am
- Forum: DeBroglie Equation
- Topic: DeBroglie
- Replies: 2
- Views: 420
Re: DeBroglie
The DeBroglie equation’s purpose it to calculate the wavelength of objects with a mass, as opposed to c=(wavelength)(frequency) which is unique for light. If given a velocity of an object, or if told to calculate the wavelength of an electron with x velocity, this is when to use the DeBroglie equati...
- Mon Dec 09, 2019 8:06 am
- Forum: DeBroglie Equation
- Topic: wavelength to remove an electron
- Replies: 3
- Views: 396
Re: wavelength to remove an electron
When they’re asking for the longest wavelength of light, using the equation c=(wavelength)(frequency), you can see that this means looking for light with the smallest frequency. Frequency correlates to energy of the photon by the equation E=h(frequency) where the smallest possible frequency would me...
- Mon Dec 09, 2019 8:02 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Hydrogen Bonding and Dipole-Dipole
- Replies: 2
- Views: 320
Re: Hydrogen Bonding and Dipole-Dipole
Hydrogen bonds and dipole dipole interactions are listed as separate intermolecular forces. Although the reason for the interaction is because the H bonded to an electronegative atom develops a more positive dipole and can therefore interact with lonepairs and other atoms, dipole dipole interactions...
- Sat Dec 07, 2019 11:34 pm
- Forum: Administrative Questions and Class Announcements
- Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
- Replies: 115
- Views: 14157
Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Kayla Maldonado 1A wrote:#16 why is the trigonal planar shape considered nonpolar, how did we determine this ?
The problem mentioned that the "X" in the AX3 were all the same atoms. Their dipole moments would therefore cancel and the molecule would be nonpolar.
- Sat Dec 07, 2019 2:08 pm
- Forum: Administrative Questions and Class Announcements
- Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
- Replies: 115
- Views: 14157
Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Nikki Razal 4E wrote:for question 40c, how do you know whether o2 or o3 has the stronger bond and why?
o3 has resonance, which is stabilizing because the electrons are delocalized and makes the bonds stronger.
- Sat Dec 07, 2019 1:54 pm
- Forum: Administrative Questions and Class Announcements
- Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
- Replies: 115
- Views: 14157
Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Lauren Haight 1E wrote:for mini marshmallow 2b, why is the coordination number for Dihydroxoyoxolatocobalt (III) 4? Is it because oxalato is bidentate and can attach to cobalt at two places?
Yes, it is because oxalato is bidentate.
- Sat Dec 07, 2019 1:45 pm
- Forum: Administrative Questions and Class Announcements
- Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
- Replies: 115
- Views: 14157
Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Tiffany Chen 1K wrote:For #31 should the name be ...nickel(III) ion? The complex has a 2+ charge.
Yes I think it should be "ion" since its a positively charged molecule
- Sat Dec 07, 2019 1:24 pm
- Forum: Biological Examples
- Topic: Charge of Iron in Hemoglobin
- Replies: 2
- Views: 426
Charge of Iron in Hemoglobin
How do you calculate the charge of the Iron in the heme complex? I know it should be 2+, but don't the nitrogens that bind to the iron have an overall charge of 2+ making the iron 2-? I know that does not make sense since iron is a cation, but based on the math isn't that what the formal charge calc...
- Sun Dec 01, 2019 12:39 pm
- Forum: Biological Examples
- Topic: Biological Examples
- Replies: 10
- Views: 535
Re: Biological Examples
Yes, biological examples will definitely be on the final. Any biological example he mentioned is fair game. The ones to know in depth based on the emphasis they were given in lecture are: cisplatin structure and how it works, ethylenediamine and EDTA relationship, Porphyrin and myoglobin relationshi...
- Sun Dec 01, 2019 12:34 pm
- Forum: Biological Examples
- Topic: Porphyrin ligand-tetradentate
- Replies: 2
- Views: 354
Re: Porphyrin ligand-tetradentate
The heme complex is created by the binding of the porphyrin tetra dentate ligand to an iron ion. When a protein is bound, this creates myoglobin which is responsible for transport of oxygen throughout the bloodstream. This happens when an O2 molecule binds to the iron. Carbon Monoxide poisoning happ...
- Sun Dec 01, 2019 12:25 pm
- Forum: Biological Examples
- Topic: EDTA
- Replies: 8
- Views: 589
Re: EDTA
EDTA has six binding sites which bind metals and remove them from a solution. The biological example would be to use EDTA to remove metals from the bloodstream.
- Sun Dec 01, 2019 12:23 pm
- Forum: Biological Examples
- Topic: Cisplatin
- Replies: 15
- Views: 720
Re: Cisplatin
DHavo_3H wrote:Hi,
Where does cisplatin bond on the DNA to stop translation, and thus cause the cell to die? Thanks in advance!
The chlorines in the cisplatin bind to the guanines in the DNA strand to stop replication.
- Sun Dec 01, 2019 12:20 pm
- Forum: Biological Examples
- Topic: Cisplatin vs Transplatin
- Replies: 2
- Views: 244
Re: Cisplatin vs Transplatin
The chlorines in the cisplatin molecule can both simultaneously bind to guanines on a DNA strand, which stops DNA replication, and therefore, cancer multiplication. The trans model cannot do this because the chlorines are on different sides, meaning they cannot both bind to the DNA strand at the sam...
- Thu Nov 21, 2019 10:48 am
- Forum: Dipole Moments
- Topic: Dipole Induced- Dipole Induced
- Replies: 13
- Views: 1206
Re: Dipole Induced- Dipole Induced
Induced Dipole - Induced Dipole interactions occur between any two molecules. Neither of the molecules has to be polar for this to occur. This means the same thing as Van Der Waals forces and London Dispersion Forces.
- Thu Nov 21, 2019 10:46 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Hybridized increases or decreases
- Replies: 3
- Views: 450
Re: Hybridized increases or decreases
hybridization just describes the mechanism of how those bonds actually form and in what form they exist. It does not change the shape.
- Thu Nov 21, 2019 10:44 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordinate bonds
- Replies: 3
- Views: 225
Re: Coordinate bonds
coordinate covalent bonds form when a ligand binds to a molecule and provides 100% of the electrons needed to create that bond.
- Thu Nov 21, 2019 10:42 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: cisplatin
- Replies: 4
- Views: 210
Re: cisplatin
The cis form of the molecule has the chlorines on the same side of the cisplatin molecule, so it can effectively bind to the guanine with both chlorines stopping the cell division process and therefore eliminating cancer cells.
- Thu Nov 21, 2019 10:41 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Bond angles in Trigonal Bipyramidal
- Replies: 4
- Views: 552
Re: Bond angles in Trigonal Bipyramidal
Yes, it has all three. The 180 degree angle is the angle between the bond sticking straight up and straight down.
- Sun Nov 17, 2019 12:33 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: regions of electron density
- Replies: 10
- Views: 548
Re: regions of electron density
Regions of electron density are the number of locations where electrons are more present. The number of regions is equivalent to how many atoms are bonded to the central atom plus any regions of lone pair electrons.
- Sun Nov 17, 2019 12:31 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Angles less than 109.5 degrees
- Replies: 5
- Views: 749
Re: Angles less than 109.5 degrees
The lone pair creates a stronger repulsion in the trigonal pyramidal shape, which is why the angle is less than 109.5. In a trigonal planar shape, there is no lone pair, so there is equal repulsion between the bonding regions creating equal 120 degree bonding angles.
- Sun Nov 17, 2019 12:27 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles for Seesaw Shape
- Replies: 2
- Views: 201
Re: Bond Angles for Seesaw Shape
I believe they are just 120 and 90.
Re: Naming
I would know basic polyatomic ions. Other than that, we have not really gone over naming so I would assume he will provide the formula.
- Sun Nov 17, 2019 12:19 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: What’s the Difference
- Replies: 6
- Views: 559
Re: What’s the Difference
Polarizability is the ability to be distorted by a cation, and polarizing is the act of distorting an anion electron cloud.
- Fri Nov 08, 2019 10:26 pm
- Forum: SI Units, Unit Conversions
- Topic: Memorizing Conversions
- Replies: 25
- Views: 1403
Re: Memorizing Conversions
Most conversion will be provided on the equations sheet.
- Fri Nov 08, 2019 10:23 pm
- Forum: Electronegativity
- Topic: Trend of Electronegativity
- Replies: 22
- Views: 2157
Re: Trend of Electronegativity
electronegativity describes the pulling power of the atom. Generally, across a period, electronegativity will increase. Down a group, it will decrease. This is due to effective nuclear charge and size of the atom. The smaller the atom, the closer to the nucleus the electrons can get, meaning that th...
- Fri Nov 08, 2019 10:14 pm
- Forum: Resonance Structures
- Topic: resonance importance?
- Replies: 7
- Views: 466
Re: resonance importance?
Why is it important to draw the resonance structure? it is important to draw all of the resonance structures because it allows us to better understand the concept of delocalization of electrons. It shows that there are certain types of bonds in the molecule, but that the bond is not located in one ...
- Fri Nov 08, 2019 10:12 pm
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate vs polar covalent
- Replies: 10
- Views: 2533
Re: Coordinate vs polar covalent
Covalent bonding occurs between two atoms that share electrons in order to complete each other's octet. With coordinate covalent bonding, a lewis base will coordinate covalently bond to a lewis acid and provide all of the electrons needed to complete the lewis acid's octet. In this case, the lewis a...
- Fri Nov 08, 2019 10:09 pm
- Forum: Octet Exceptions
- Topic: octet exceptions
- Replies: 11
- Views: 610
Re: octet exceptions
Elements in the third energy level and higher can have more than an octet. This is because they have empty d orbitals available to hold the extra electrons.
- Fri Nov 08, 2019 10:06 pm
- Forum: Octet Exceptions
- Topic: Lewis Acids and Bases?
- Replies: 11
- Views: 561
Re: Lewis Acids and Bases?
Lewis acids accept electron pairs and lewis bases donate that electron pair. The example that Dr. Lavelle used was with BF3 as a lewis acid and F- as a lewis base. Since Fluorine does not make double bonds, and since three fluorines bonded to a boron atom only gives boron 6 valence electrons, the on...
- Sun Oct 27, 2019 10:49 pm
- Forum: Lewis Structures
- Topic: Lone Pairs
- Replies: 12
- Views: 613
Re: Lone Pairs
As long as each atom in a molecule has an octet, including lone pairs, that is how you figure it out. When trying to determine whether to draw a lone pair or to add another bond, calculate formal charge to see what is optimal (always aim for formal charge of 0 on each atom).
- Sun Oct 27, 2019 10:45 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Bonds
- Replies: 14
- Views: 1140
Re: Covalent Bonds
What did Dr. Lavelle mean when he said non-metals do not form cation because their ionization energies are too high? He meant that since their ionization energies are too high, meaning that a very large amount of energy is required to remove one of their valence electrons, they will not lose electr...
- Sun Oct 27, 2019 10:42 pm
- Forum: Bond Lengths & Energies
- Topic: Delocalization
- Replies: 3
- Views: 179
Re: Delocalization
Delocalization of electrons occurs in resonance structures. This is why, experimentally, all bond lengths are the same even if one of the molecule's bonds is a single and the other a double. The electrons do not stay localized to only one of the bonds, and instead they move around the molecule, caus...
- Sun Oct 27, 2019 10:38 pm
- Forum: Bond Lengths & Energies
- Topic: C-C bond lengths
- Replies: 4
- Views: 238
Re: C-C bond lengths
When there is resonance, the electrons are delocalized and not bound to a specific bond in the molecule. The bond lengths are blended.
- Sun Oct 27, 2019 10:35 pm
- Forum: Bond Lengths & Energies
- Topic: bond lengths for single or double bonds
- Replies: 7
- Views: 455
Re: bond lengths for single or double bonds
Double bonds are stronger, and therefore shorter, than single bonds. However, in resonance structures, each bond is somewhere between the length of a double and single bond.
- Sun Oct 20, 2019 10:11 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Spin numbers
- Replies: 4
- Views: 195
Re: Spin numbers
You cannot determine the spin of an electron, you just know that one spins up and the other spins down. The spins means more or less the direction of which the electron in moving around the nucleus. Electrons spin in opposite direction in the same subshell in order to maximize stability.
- Sun Oct 20, 2019 10:05 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Order or orbitals
- Replies: 5
- Views: 238
Re: Order or orbitals
Can someone explain the reason for why copper and chromium are exceptions to the normal filling rule?
- Sun Oct 20, 2019 9:51 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Hund's rule and Pauli Exclusion Principle
- Replies: 14
- Views: 863
Re: Hund's rule and Pauli Exclusion Principle
They both relate to the properties of each energy subshell. Each subshell can only hold 2 electrons, according to the Pauli Exclusion Principle. The two electrons in that subshell must have opposite spins as to maximize stability, according to Hund's Rule.
- Sun Oct 20, 2019 9:46 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Opposite Spin
- Replies: 5
- Views: 316
Re: Opposite Spin
Aside from not being able to have the same four quantum numbers, electrons with opposite spin in the same subshell will maximize stability.
- Sun Oct 20, 2019 9:38 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: s-, p-, d- ,f- orbitals
- Replies: 10
- Views: 507
Re: s-, p-, d- ,f- orbitals
Can anyone explain how to list the orbitals for an element. Dr. Lavelle went over it in lecture but he did not explain the process fully. They follow the order of the periodic table. Hydrogen and Helium are in the first row, and have electrons in the s-block. The next two elements in the second row...
- Sun Oct 13, 2019 11:59 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: En=-hR/n^2
- Replies: 3
- Views: 343
Re: En=-hR/n^2
Ami_Pant_3H wrote:For clarification, is this equation only used in terms of hydrogen atoms? If so, is there a more general equation that applies to other atoms?
only applies to hydrogen atoms
- Sun Oct 13, 2019 11:57 am
- Forum: Limiting Reactant Calculations
- Topic: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
- Replies: 68
- Views: 7434
Re: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
Cassandra_1K wrote:For limiting reactants on the test do we have to explain how we know one is a limiting reactant or can we just specify which one?
just specify which one
- Sun Oct 13, 2019 11:56 am
- Forum: Limiting Reactant Calculations
- Topic: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
- Replies: 68
- Views: 7434
Re: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
I don't think that every single simple step needs to be shown, but someone who does not know much about chemistry or who would be confused easily should be able to follow along and understand how you got from point A to B.