Search found 66 matches
- Sat Mar 16, 2019 10:00 pm
- Forum: Administrative Questions and Class Announcements
- Topic: LYNDON'S PORK RAMEN REVIEW
- Replies: 37
- Views: 7468
Re: LYNDON'S PORK RAMEN REVIEW
lyndon da goat fr fr
- Tue Mar 12, 2019 9:43 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: pre-equilibrium question
- Replies: 2
- Views: 358
Re: pre-equilibrium question
Only everything before the intermediate being formed contributes to the rate law so if it comes after the slow step it is not really accounted for.
- Tue Mar 12, 2019 9:41 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Pre-equilibrium vs. steady-state
- Replies: 4
- Views: 507
Re: Pre-equilibrium vs. steady-state
the steady step is never used in this class according to Dr. Lavelle since it requires too much math.
- Tue Mar 12, 2019 9:40 pm
- Forum: Zero Order Reactions
- Topic: Reaction Rate
- Replies: 10
- Views: 1209
Re: Reaction Rate
k is a specific for a certain temperature, so if the reaction takes place at the specified temperature then the k would be the same.
- Thu Mar 07, 2019 3:51 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Order of Reaction
- Replies: 5
- Views: 690
Re: Order of Reaction
The graph posted above is a great tool to use in order to understand the order of reactions.
- Thu Mar 07, 2019 3:43 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Rate constant k
- Replies: 3
- Views: 471
Re: Rate constant k
Temoerature and the addition of enzymes would affect the rate constant, as temperature plays a significant role when determining chemical reaction rates.
- Sun Mar 03, 2019 7:32 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell diagrams and solids
- Replies: 9
- Views: 991
Re: Cell diagrams and solids
The electrons can not be conducted by themselves therefore an inert solid like Platinum could be used to transfer the electrons over to the other side.
- Sun Mar 03, 2019 7:31 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagrams (Using Platinum)
- Replies: 10
- Views: 978
Re: Cell Diagrams (Using Platinum)
We use platinum because It is highly inert and is great conductor therefore it is used when there are no present solids
- Sun Mar 03, 2019 7:29 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Does anyone know if test 2 will be curved?
- Replies: 15
- Views: 2984
Re: Does anyone know if test 2 will be curved?
the probability of this test being curved is very unlikely since the class itself is not curved.
- Sun Mar 03, 2019 7:27 pm
- Forum: Balancing Redox Reactions
- Topic: Test #2
- Replies: 10
- Views: 1095
Re: Test #2
The higher the reduction potential the easier it is for a species to be reduced and the lower the reduction potential the easier it is foe a species to be oxidized.
- Sun Mar 03, 2019 7:26 pm
- Forum: Balancing Redox Reactions
- Topic: Strength of reducing agent
- Replies: 10
- Views: 1881
Re: Strength of reducing agent
The more positive a reduction potential is the easier it is for it to be reduced, and vice versa for an element to be oxidized. Therefore a lower reduction potential would make the best reducing agent.
- Sun Mar 03, 2019 7:25 pm
- Forum: Balancing Redox Reactions
- Topic: Acidic vs basic solutions
- Replies: 10
- Views: 1018
Re: Acidic vs basic solutions
Both are balanced by adding water molecules to a the reactants or products, but for acidic reactions, they are balanced with H^+ while basic reactions are balanced by adding hydroxides to a side.
- Thu Feb 21, 2019 8:52 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs Free Energy Meaning
- Replies: 6
- Views: 739
Re: Gibbs Free Energy Meaning
Gibbs free energy is the total amount o energy available to preform work as not all the energy of the system can be converted to work since it is impossible to fully convert energy to work as some energy would be lost through other means.
- Thu Feb 21, 2019 8:50 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Delta H
- Replies: 5
- Views: 591
Re: Delta H
A change In enthalpy alone cannot determine the spontaneous nature of a system as the entropy of the system and the temperature the reaction is taking place at are also needed to determine the spontaneity of a reaction.
- Thu Feb 21, 2019 8:49 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Units of Delta G
- Replies: 5
- Views: 7623
Re: Units of Delta G
The units for delta G happen to be the same for enthalpy which are J, Kj, KJ/mol, J/mol.
- Thu Feb 21, 2019 8:48 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs Free Energy vs Entropy
- Replies: 4
- Views: 787
Re: Gibbs Free Energy vs Entropy
Gibbs free energy is the amount of energy available that can be used to preform work with entropy measures the disorder of the system. Gibbs free energy is so important because it allows us to determine if a reaction would proceed by itself to form products which is crucial under standard temp and p...
- Thu Feb 21, 2019 8:45 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Negative ∆G means spontaneous reaction?
- Replies: 5
- Views: 6830
Re: Negative ∆G means spontaneous reaction?
Yes a negative value resulting from the Gibbs free energy equation means that the reactants will make products spontaneously.
- Mon Feb 04, 2019 4:33 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Open vs Closed System
- Replies: 13
- Views: 4520
Re: Open vs Closed System
The simplest way to put it is that in an open system heat and material can be exchanged, in a closed system only heat can be exchanged with the surroundings, but in an isolated system nothing can be exchanged with the surroundings.
- Mon Feb 04, 2019 4:30 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Constant P
- Replies: 4
- Views: 435
Re: Constant P
At standard pressure, the pressure equals 1 atm, but unless otherwise specified it can be different.
- Sun Feb 03, 2019 8:56 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: delta H vs q
- Replies: 9
- Views: 904
Re: delta H vs q
Delta H represent the heat that changed in reaction, while q represents the heat.
- Sun Feb 03, 2019 8:51 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: finding W
- Replies: 6
- Views: 607
Re: finding W
Yes, the integral just implies that a very small volume is being changed at every instant therefore it all can be summed up with an integral, while if the change of volume is large and sudden ten delta v can just be used.
- Tue Jan 29, 2019 8:07 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: What is the difference between delta H and q?
- Replies: 3
- Views: 1644
Re: What is the difference between delta H and q?
q just refers to heat while delta h refers to the change of heat within a specific reaction under standard and constant pressure
- Tue Jan 29, 2019 8:01 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Best Method
- Replies: 7
- Views: 804
Re: Best Method
It all depends on the initial information given in the problem, there is no true best way to solve this questions but some options are better for certain types of questions.
- Tue Jan 29, 2019 7:57 pm
- Forum: Phase Changes & Related Calculations
- Topic: State Properites
- Replies: 7
- Views: 626
Re: State Properites
State properties do not depend on the path that is taken to achieve the current state while properties such as work and heat do depend on which pathway is taken.
- Tue Jan 29, 2019 7:55 pm
- Forum: Phase Changes & Related Calculations
- Topic: Standard entalpy of formation
- Replies: 6
- Views: 1033
Re: Standard entalpy of formation
When a molecule is at its basic state(elemental form including diatomic atoms) the standard enthalpy of formation is 0
- Tue Jan 29, 2019 7:46 pm
- Forum: Phase Changes & Related Calculations
- Topic: Delta Hº versus delta H
- Replies: 7
- Views: 7393
Re: Delta Hº versus delta H
They mean the same thing, one is just referring to the initial delta H.
- Tue Jan 29, 2019 7:45 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy signs
- Replies: 13
- Views: 1667
Re: Enthalpy signs
The enthalpy change is positive when a reaction gains heat (endothermic reaction) and is negative when the reactants release energy to the universe (exothermic reactions)
- Tue Jan 29, 2019 7:43 pm
- Forum: Phase Changes & Related Calculations
- Topic: Heat Capacity
- Replies: 10
- Views: 936
Re: Heat Capacity
Heat Capacity is the energy required to raise the temp by one degree Celsius while the molar heat capacity is the energy required to raise the temperature of one mole of substance by one degree celsius.
- Mon Jan 21, 2019 3:02 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Inert Gases
- Replies: 7
- Views: 826
Re: Inert Gases
Inert gases are excluded from the equilibrium expression because they do not change the equilibrium concentration nor presser of the aqueous or gaseous species.
- Mon Jan 21, 2019 3:00 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 5% rule
- Replies: 12
- Views: 21590
Re: 5% rule
When dealing with weak acids or bases, the 5% rule can be applied to neglect the change of the reactants towards the products in order to make calculating the change significantly easier without use of the quadratic formula.
- Mon Jan 21, 2019 2:57 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change in temperature's effect on K
- Replies: 4
- Views: 343
Re: Change in temperature's effect on K
If the reaction is endothermic then increasing the heat would favor an equilibrium sitting to towards the product. Decreasing the heat would favor an equilibrium sitting towards the reactants. For exothermic the process is reversed as expected.
- Mon Jan 21, 2019 2:52 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: The Conjugate Seesaw
- Replies: 13
- Views: 956
Re: The Conjugate Seesaw
In very simple terms the conjugate seesaw basically states that the stronger the base or acid is, the weaker its conjugate acid or base is.
- Mon Jan 21, 2019 2:51 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Weak acid and its salt
- Replies: 3
- Views: 223
Re: Weak acid and its salt
As mentioned in 14A, Group 1 mentally and group 17 halogens do not affect the pH of a solution at all. On the other hand group two metals slightly change the pH but not by a drastic amount.
- Mon Jan 21, 2019 2:49 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Pure substances
- Replies: 3
- Views: 309
Re: Pure substances
While at equilibrium only aqueous and liquid species are represented in the equilibrium expression as they are the only species can change the concentrations.
- Mon Jan 21, 2019 2:45 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Temperature for Equilibrium
- Replies: 4
- Views: 301
Re: Temperature for Equilibrium
Most equilibrium expressions will be given at 25 C or 298K, but this is not mandatory as equilibrium can occur at any given temperature depending on the species.
- Mon Jan 21, 2019 2:44 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Strong acids and bases
- Replies: 4
- Views: 478
Re: Strong acids and bases
Strong acids and bases can also be recognized by their percent dissociation. Strong bases and acids fully dissociate while weak ones hardly do.
- Mon Jan 21, 2019 2:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Water in ICE tables
- Replies: 10
- Views: 2591
Re: Water in ICE tables
Since water is a pour solvent in can be left out of the ice table when calculating equilibrium concentrations since it is in excess.
- Wed Dec 05, 2018 8:55 pm
- Forum: Bronsted Acids & Bases
- Topic: acetic acid vs formic acid
- Replies: 2
- Views: 387
Re: acetic acid vs formic acid
The strength of an acid is all in relation to how easily the Hydrogen proton can separate from the compound, in this case, it is easier for formic acid to lose a hydrogen proton.
- Wed Dec 05, 2018 8:51 pm
- Forum: Bronsted Acids & Bases
- Topic: Water as an Acid or Base
- Replies: 4
- Views: 529
Re: Water as an Acid or Base
Due to it's neutral pH, water can be considered as either a base or an acid. It could gain a proton and become hydronium or lose a proton and become hydroxide.
- Wed Dec 05, 2018 8:45 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: “Soapy” feel of bases
- Replies: 5
- Views: 2496
Re: “Soapy” feel of bases
Bases have the unique ability of dissolving acids, therefore when they interact with our oily skin, a slippery feel is produced.
- Wed Dec 05, 2018 8:43 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: HF ion
- Replies: 3
- Views: 535
Re: HF ion
The bond length between the Hydrogen and Flourine atom is very small due to FLourine's high electronegativity, therefore it is harder for the Hydrogen ion to dissociate.
- Sun Dec 02, 2018 4:17 pm
- Forum: Hybridization
- Topic: Hybridization
- Replies: 2
- Views: 344
Re: Hybridization
They are completely different atomic orbitals are the electrons surrounding an atom, while hybridization refers to the mixing of different orbitals to form a mixture of bonds.
- Tue Nov 27, 2018 8:20 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test 3
- Replies: 38
- Views: 2568
Re: Test 3
the best way of identifying molecular shapes is by memorizing the designated shape according to how many species and lone pairs there are
- Tue Nov 27, 2018 8:14 pm
- Forum: Hybridization
- Topic: Molecular Shape
- Replies: 2
- Views: 155
Re: Molecular Shape
Yes lone pairs play a very important role in hybridization as they determine what energy levels are hybridized, therefore lone pairs must be accounted for since they allow for the correct hybridized species to be identified.
- Tue Nov 27, 2018 8:10 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sigma and Pi bonds
- Replies: 4
- Views: 473
Re: Sigma and Pi bonds
The main difference between sigma and pi bonds is that sigma bonds consist of one bond, while pi bonds consist of 2 bonds. Another difference between these two bonds is that sigma bonds allow for rotation while sigma bonds do not allow for any movement.
- Sun Nov 18, 2018 1:47 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Dipole-Dipole forces
- Replies: 4
- Views: 486
Re: Dipole-Dipole forces
Dipole-dipole forces occur when their a great difference between the electronegativity of two atoms. When determining the dipole forces it is important to consider if they cancel or not because then polarity can be inferred.
- Sun Nov 18, 2018 1:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 16
- Views: 1185
Re: Bond Angles
Each molecular shape has its own respective bond angles, the easiest way to figure out these angles is just by memorizing them.
- Sun Nov 18, 2018 1:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: lone pairs
- Replies: 11
- Views: 868
Re: lone pairs
Yes, Dr. Lavelle goes into great detail about this phenomenon as lone electrons repel atoms away.
- Thu Nov 08, 2018 5:00 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Potential Energy of London interactions
- Replies: 2
- Views: 604
Re: Potential Energy of London interactions
London Forces are the weakest forms of bonds created by instances moments of ionization, therefore bond length does not necessarily matter when discussing these bonds as their potential energy Is more influenced on the type of bond rather than distance.
- Thu Nov 08, 2018 4:43 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Effect of Size of Atom/Molecule on Distortion
- Replies: 2
- Views: 329
Re: Effect of Size of Atom/Molecule on Distortion
The size of an atom is determined by its atomic number, as the higher the atomic number gets the more protons are located in the nucleus and more electrons in the electron sphere thus making the atom larger. They all have something to do with the size of an atom
- Thu Nov 08, 2018 4:41 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Dipole Moment
- Replies: 3
- Views: 384
Re: Dipole Moment
Dipole moments occur instanously as electrons are pulled or pushed away by the electronegativity of the neighboring atom. These interactions are instances and last for a short period of time as electrons are continuously being pulled or pushed away. These instaneous shifts of electrons creates posit...
- Thu Nov 01, 2018 5:31 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Bonds
- Replies: 16
- Views: 1586
Re: Covalent Bonds
Non metals generally do not become cations because they have a very high electron affinity therefore their ionization energies would be very high making it unlikely for them to lose an electron.
- Thu Nov 01, 2018 5:21 pm
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate Covalent Bond Definition
- Replies: 14
- Views: 1824
Re: Coordinate Covalent Bond Definition
Yes! Instead of one electron coming from each atom, a coordinate covalent bond uses two electrons that come from the same atom.
- Thu Nov 01, 2018 5:14 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal charge purpose
- Replies: 40
- Views: 7089
Re: Formal charge purpose
Formal charge has to be considered when drawing lewis structures as it will help you figure out if there is a double bond or not while trying to figure out the most stable form of the compound.
- Fri Oct 26, 2018 12:26 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Shielding effect
- Replies: 6
- Views: 1139
Re: Shielding effect
Shielding protects the outer electrons from the pull of the nucleus through the inner electrons absorbing the pull.
- Thu Oct 25, 2018 11:53 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Degeneracy
- Replies: 7
- Views: 3315
Re: Degeneracy
As far as degeneracy is concerned it is important to know that electrons in the same hydrogen atom have the same energy level. However, multi electron systems are not degenerate as with different sub shells there are different energies.
- Thu Oct 25, 2018 11:47 pm
- Forum: DeBroglie Equation
- Topic: De Broglie wavelengths
- Replies: 3
- Views: 290
Re: De Broglie wavelengths
De Brogile equation is used for any object with moment and wavelength, so in reality it could be applied to almost all scenarios although it would be pointless if it used on an object with a large wavelength.
- Tue Oct 16, 2018 6:04 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Balmer/Lyman... Series
- Replies: 4
- Views: 354
Re: Balmer/Lyman... Series
In regards to energy, the Lyman and Balmer series allow us to infer where the electron returns back to ground state. In the Lyman series, n=1 so the electron would lose energy and return to the first energy level. On the other hand, when using the Balmer series, we can infer that the electron return...
- Tue Oct 16, 2018 5:59 pm
- Forum: Photoelectric Effect
- Topic: 1B.9: Trouble with exponents and units
- Replies: 3
- Views: 989
Re: 1B.9: Trouble with exponents and units
To solve this question, you must calculate the total amount of energy released (32W x 2s)=64J and then consider the energy released by one photon with a wavelength 420nm, then divide the total energy/the energy of one photon. This will result in the correct answer. Also consider the appropriate SI u...
- Tue Oct 16, 2018 5:53 pm
- Forum: Properties of Electrons
- Topic: Energy emitted by electrons
- Replies: 6
- Views: 533
Re: Energy emitted by electrons
When considering the release of energy, it is important to remember that energy can not be created nor destroyed, only transferred. With this in mind, the energy released from an excited electron does not disappear, but instead is released into the universe thus conserving the total energy from the ...
- Thu Oct 11, 2018 2:22 pm
- Forum: Photoelectric Effect
- Topic: Threshold energy
- Replies: 5
- Views: 4468
Re: Threshold energy
The threshold value needed to remove an electron can be treated like any other requirement needed before an action can occur. A particle needs to have a minimum amount (varying on the type of substance) of energy in order for an electron to be ejected. Taking this into consideration, if we know how ...
- Thu Oct 11, 2018 2:15 pm
- Forum: Properties of Light
- Topic: Balmer series vs Lyman series
- Replies: 4
- Views: 220
Re: Balmer series vs Lyman series
The main difference between the two series is the quantum levels they encompass. The Lyman series includes quantum level one which is why ultraviolet radiation is observed within this series(the leap from n=1 to n=2 realeses more energy than any other quantum jump that is why the radiation is uv.) O...
- Thu Oct 11, 2018 2:02 pm
- Forum: Properties of Light
- Topic: Why Short Wavelengths Can Eject e-
- Replies: 6
- Views: 959
Re: Why Short Wavelengths Can Eject e-
Longer wavelengths have less energy than shorter wavelengths due the energy = hc/wavelength formula that denotes that if the wavelength increases, then the energy of the particle will decrease which establishes a negative correlation. In conclusion, shorter wavelengths shoot out electrons compared t...
- Mon Oct 01, 2018 6:32 pm
- Forum: Balancing Chemical Reactions
- Topic: Law of Conservation of Mass [ENDORSED]
- Replies: 7
- Views: 1025
Re: Law of Conservation of Mass [ENDORSED]
This is as simple as it gets: mass can not be created and mass cannot be destroyed. There will always be the same amount mass before and after a chemical reaction since mass cannot be created nor destroyed.
- Mon Oct 01, 2018 6:28 pm
- Forum: Significant Figures
- Topic: Significant Figures
- Replies: 10
- Views: 2865
Re: Significant Figures
The full value of molar mass can be used to calculate whatever needs to be calculated, but the least amount of sig figs must be used when determining the final answer, as it would be inaccurate to have an answer that is more than the initial significant figures there given.
- Mon Oct 01, 2018 6:17 pm
- Forum: SI Units, Unit Conversions
- Topic: Grams/mole
- Replies: 12
- Views: 1157
Re: Grams/mole
Both g/mol and gmol^-1 represent grams divided by moles while the latter just uses textbook notation in order to represent that grams is being divided by moles in a more comprehensive way. Feel free to use either or as they both represent the same thing.