Search found 109 matches
- Sat Mar 14, 2020 4:24 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation/Reduction
- Replies: 17
- Views: 1118
Re: Oxidation/Reduction
In Test 2, we were asked what species was being oxidized/reduced and for those, we looked at the molecule being reduced or oxidized.
- Sat Mar 14, 2020 4:18 pm
- Forum: Balancing Redox Reactions
- Topic: Half rxns
- Replies: 27
- Views: 1359
Re: Half rxns
There are two really helpful resources on Lavelle's website where it tells you what to do for acidic and basic solutions. From that, you can see what differs basic rxns from acidic rxns.
- Sat Mar 14, 2020 4:17 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in NFE
- Replies: 64
- Views: 2956
Re: n in NFE
N stands for the number of electrons transferred. So you would have to separate your redox rxns into the reduction and oxidation rxn in order to see how many electrons are being transferred after you balanced both reactions.
- Sat Mar 14, 2020 4:15 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Test 2 on Standard Cell Potential
- Replies: 6
- Views: 421
Re: Test 2 on Standard Cell Potential
To determine which rxn is your anode or cathode, remember that your highest Ecell would be your cathode and your lowest one would be your anode. Then when determining Gibbs free energy, you would use -nFE in order to figure it out.
- Sat Mar 14, 2020 4:09 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: inert gases
- Replies: 6
- Views: 409
Re: inert gases
what of the elements such as platinum that seem to be attached to a cell diagram? Pt(s) is used as a conductor when there is no conductive solid participating in the redox reaction. It is added to the cell diagram but does not participate. Platinum is just used as a conductor when there is no condu...
- Sat Mar 14, 2020 4:07 pm
- Forum: Balancing Redox Reactions
- Topic: Determing balanced rxns for a basic solution
- Replies: 5
- Views: 436
Re: Determing balanced rxns for a basic solution
There is a step-by-step PDF on Lavelle's website that is super clear and concise when balancing rxns for basic solutions. I have attached it below:
https://lavelle.chem.ucla.edu/wp-conten ... itions.pdf
https://lavelle.chem.ucla.edu/wp-conten ... itions.pdf
- Sat Mar 14, 2020 4:05 pm
- Forum: Balancing Redox Reactions
- Topic: Acid or base?
- Replies: 5
- Views: 488
Re: Acid or base?
We should be given the information in the question whether it is basic or acidic, whether it is explicitly stated or they give us the pH.
- Sat Mar 14, 2020 4:04 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2 Return
- Replies: 20
- Views: 1151
Re: Test 2 Return
My TA said we would be able to pick it up from the graduate mailbox in Young Hall.
- Sat Mar 14, 2020 4:03 pm
- Forum: Balancing Redox Reactions
- Topic: QD3 Midterm
- Replies: 5
- Views: 426
Re: QD3 Midterm
You are assuming that acetic acid dissolved into CHCH3COO- and H+ due to the pH of 6.
- Sat Mar 14, 2020 3:59 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: E potential
- Replies: 8
- Views: 520
Re: E potential
Yes, the cathode is always (I think) the highest Epotential and the lowest one is the anode.
- Sat Mar 14, 2020 3:57 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Lyndon Review: 1D
- Replies: 5
- Views: 496
Re: Lyndon Review: 1D
If you are referring to the mass of the anode being increased, then the Ecell would not be affected. The mass does not affect the Ecell. As stated before, I believe this was a question on Test 2.
- Sun Mar 01, 2020 11:28 pm
- Forum: Second Order Reactions
- Topic: does the order determine molecularity?
- Replies: 7
- Views: 894
Re: does the order determine molecularity?
Yes it does!
- Sun Mar 01, 2020 11:26 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Determining n
- Replies: 5
- Views: 432
Determining n
How do you determine n? I find it pretty confusing at times.
- Sun Mar 01, 2020 11:24 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3008737
Re: Post All Chemistry Jokes Here
Q: What kind of dogs do chemists have?
A: Laboratory Retrievers.
A: Laboratory Retrievers.
- Sun Mar 01, 2020 11:22 pm
- Forum: General Rate Laws
- Topic: Order
- Replies: 5
- Views: 502
Re: Order
You can look at the graphs provided or you can look at the units used in a specific problem if they do not specifically tell you which order it is. That is why it is important to know and memorize the units for the orders!
- Sun Mar 01, 2020 11:20 pm
- Forum: General Rate Laws
- Topic: Integrated Rate Law
- Replies: 5
- Views: 351
Re: Integrated Rate Law
The differential rate law is rxn rate as a function of reactant concentration. The integrated rate law tells us how much reactant concentration changes over time, so we add the variable time to it.
- Sun Mar 01, 2020 11:18 pm
- Forum: General Rate Laws
- Topic: tangent lines
- Replies: 5
- Views: 431
Re: tangent lines
You can just take the derivative to make it easier.
- Sun Feb 23, 2020 11:34 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2 Topics
- Replies: 7
- Views: 486
Re: Test 2 Topics
Test 2 includes the last page on Thermodynamics and what we have learned so far in Electrochemistry!
- Sun Feb 23, 2020 11:33 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2
- Replies: 9
- Views: 510
Re: Test 2
The test will be during Week 9 whenever you have your discussion!
- Sun Feb 23, 2020 11:32 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: State
- Replies: 5
- Views: 349
Re: State
It should be given right next to the molecule, based on the context of the problem.
- Sun Feb 23, 2020 11:30 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Difference in phases
- Replies: 5
- Views: 305
Re: Difference in phases
The single line represents molecules in different phases, whereas a comma separates the molecules but represents the same phase.
- Sun Feb 23, 2020 11:29 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Positive or Negative Sign
- Replies: 4
- Views: 277
Re: Positive or Negative Sign
As stated above, you would change the sign to positive or negative depending on the direction of the reaction from the standard reduction potential. That is why it is also very important to know whether a half reaction is an oxidation or reduction.
- Sun Feb 23, 2020 11:26 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: salt bridge
- Replies: 5
- Views: 413
Re: salt bridge
A salt bridge maintains electrical neutrality within the internal circuit, which prevents the cell from rapidly running its reaction to equilibrium. When there is no net change anymore, the cell can no longer do work.
- Sun Feb 23, 2020 11:24 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Platinum
- Replies: 2
- Views: 228
Platinum
Why did we use platinum on Friday in Lavelle's lecture? In what cases would we use it?
- Sun Feb 16, 2020 11:07 pm
- Forum: Balancing Redox Reactions
- Topic: How do you combine half reactions together?
- Replies: 2
- Views: 141
How do you combine half reactions together?
How do you combine half reactions together?
- Sun Feb 16, 2020 11:05 pm
- Forum: Balancing Redox Reactions
- Topic: Reduction vs. oxidation
- Replies: 29
- Views: 1125
Re: Reduction vs. oxidation
As mentioned before, oxidation is losing electrons while reduction is gaining electrons. You can either memorize "the LEO goes GER" or OIL RIG.
- Sun Feb 16, 2020 11:04 pm
- Forum: Balancing Redox Reactions
- Topic: Electrochemisty
- Replies: 10
- Views: 619
Re: Electrochemisty
The answer to this might be obvious but how does this connect to batteries? At a basic level, batteries are storage places for chemical reactions to occur. These chemical reactions can be used to generate electrical energy for our usage. In addition, Professor Lavelle mentioned on Friday that when ...
- Sun Feb 16, 2020 11:02 pm
- Forum: Balancing Redox Reactions
- Topic: Memorizing charges
- Replies: 11
- Views: 682
Re: Memorizing charges
I believe we are expected to memorize the most common ones and it also good practice!
- Sun Feb 16, 2020 11:01 pm
- Forum: Balancing Redox Reactions
- Topic: Why do we split equations?
- Replies: 12
- Views: 747
Why do we split equations?
I understand that splitting equations means separating the reduction equation from the oxidation equation but what is the purpose?
- Sun Feb 16, 2020 10:58 pm
- Forum: Balancing Redox Reactions
- Topic: redox reaction
- Replies: 10
- Views: 551
Re: redox reaction
An acronym that I find very useful is as mentioned above, OIL RIG. Oxidation is losing electrons, reduction is gaining electrons.
- Mon Feb 10, 2020 12:05 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: HW 4D7
- Replies: 4
- Views: 129
Re: HW 4D7
For gases, the change in enthalpy is defined by that equation. This is because when gas is produced work is done to clear the other gases so the enthalpy is lower than the internal energy. This is explained in detail on pg 274 in the textbook (4D.2) Thank you so much for explaining! Do you know why...
- Mon Feb 10, 2020 12:00 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Pizza Rolls - State Functions
- Replies: 5
- Views: 275
Re: Pizza Rolls - State Functions
The acronym is PD, TV HUGS.
- Sun Feb 09, 2020 11:58 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: when to change sign of enthalpies
- Replies: 7
- Views: 370
Re: when to change sign of enthalpies
If you mean 4A, we change the sign of enthalpies when we reverse the equation. For example, we reversed equation 2 because we wanted Vodka on the product side since we have it on the product side in the overall recipe. We then multiplied it by two since we want 2 Vodka on the product side to match t...
- Sun Feb 09, 2020 11:53 pm
- Forum: Phase Changes & Related Calculations
- Topic: Homework Problem 4C.13
- Replies: 3
- Views: 167
Re: Homework Problem 4C.13
It is very helpful to draw the graph. We see that in order to melt ice, we need to go through the plateau on the heating curve that turns a solid into liquid. So we have to include that in our calculations .
- Sun Feb 09, 2020 11:49 pm
- Forum: Phase Changes & Related Calculations
- Topic: 4B.5
- Replies: 7
- Views: 426
Re: 4B.5
We know that internal energy is q+w. We know from the question that q is 5.50kJ. Now we need to figure out the work done. Thus, we would be using the equation w = -PΔV to figure that out. Then when work is calculated, we add 5.50kJ + work done and that will be the change in internal energy.
- Sun Feb 09, 2020 11:45 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: HW 4D7
- Replies: 4
- Views: 129
HW 4D7
For 4D7, why are we using the equation DeltaH= DeltaU + DeltaNRT? I do not quite understand why we are including DeltaNRT.
- Sun Feb 09, 2020 11:37 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4C7
- Replies: 1
- Views: 108
4C7
For 4C7, I know we calculated the enthalpy of vaporization for part b by turning 22.45g of ethanol into moles (which gives you 0.48), and then dividing 21.2kJ of energy by 0.48. This, in turn gives you 44.16 for the enthalpy of vaporization but I do not understand the question conceptually. Why are ...
- Sun Feb 09, 2020 11:32 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4D3
- Replies: 1
- Views: 91
4D3
For Part B on 4D3, I was a little confused on why we would use 1.40g of carbon monoxide to calculate the internal energy (converting that into moles) instead of 1.00 mol CO(g) which was what was given on part b. I might be totally reading the question wrong, but can someone explain it?
- Mon Jan 27, 2020 12:11 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Reversible Reactions
- Replies: 3
- Views: 229
Re: Reversible Reactions
A chemical rxn is reversible when it can convert back to the reactants. For example, combustion is irreversible since its entirety was "consumed." For reversible rxns, the reactants are never fully consumed or dissociated/ionized.
- Mon Jan 27, 2020 12:06 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Water Phase Change
- Replies: 6
- Views: 161
Re: Water Phase Change
As mentioned above, the molecules of water are held together by hydrogen bonding; breaking those bonds require a great amount of energy.
- Mon Jan 27, 2020 12:04 am
- Forum: Phase Changes & Related Calculations
- Topic: Chem 14A Final Pickup
- Replies: 8
- Views: 340
Re: Chem 14A Final Pickup
You will still be able to pick up your Final this week!
- Mon Jan 27, 2020 12:03 am
- Forum: Phase Changes & Related Calculations
- Topic: 3 Methods
- Replies: 4
- Views: 113
Re: 3 Methods
We will most likely be using all three; it definitely depends on what the question is asking. However, keep in mind that Method 2 is the least accurate as mentioned in lecture.
- Mon Jan 27, 2020 12:02 am
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy
- Replies: 5
- Views: 171
Re: Enthalpy
Enthalpy is a state function because it only depends on initial and final values in the rxn; thus, the path doesn't matter.
- Mon Jan 27, 2020 12:00 am
- Forum: Phase Changes & Related Calculations
- Topic: Hess's Law
- Replies: 5
- Views: 144
Re: Hess's Law
Similarly to the former statement, Hess' law allows us to combine equations to generate new rxns whose enthalpy change can be calculated, since it is a state function.
- Sun Jan 19, 2020 11:35 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs Q
- Replies: 14
- Views: 317
Re: K vs Q
K is a constant used when the rxn is at equilibrium. Q can be used at any time in the rxn to determine the shift of a rxn, either left or right.
- Sun Jan 19, 2020 11:30 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Relationship between pressure and volume
- Replies: 10
- Views: 390
Re: Relationship between pressure and volume
As formerly mentioned, pressure and volume are inversely proportional. When volume decreases, pressure increases. When volume increases, pressure decreases.
- Sun Jan 19, 2020 11:27 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Effect of increasing pressure on reactions
- Replies: 6
- Views: 240
Re: Effect of increasing pressure on reactions
The reaction would shift towards the side with fewer moles!
- Sun Jan 19, 2020 11:22 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5% rule
- Replies: 8
- Views: 216
Re: 5% rule
We test it out by dividing equilibrium concentration/initial concentration x 100. if the value is less than 5%, the approximation is valid.
- Sun Jan 19, 2020 11:18 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction Shifts Left or Right
- Replies: 15
- Views: 530
Re: Reaction Shifts Left or Right
The reaction will shift to the left because the reverse reaction is endothermic. Increasing heat/temperature will cause the rxn to favor the reactants.
- Sun Jan 12, 2020 5:54 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: appliction of principle
- Replies: 5
- Views: 211
Re: appliction of principle
Le Chatelier's Principle applies to changes in temperature, volume or concentration.
- Sun Jan 12, 2020 5:52 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Units for K
- Replies: 21
- Views: 591
Re: Units for K
Equilibrium constants have no units; this is because it is a ratio of similar quantities.
- Sun Jan 12, 2020 5:32 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction shifts right or left?
- Replies: 14
- Views: 1498
Re: Reaction shifts right or left?
If the rxn shifts left, that means that a forward reaction is favored, thus producing more reactants. If the rxn shifts right, that means that a reverse reaction is favored, thus producing more products.
- Sun Jan 12, 2020 5:28 pm
- Forum: Ideal Gases
- Topic: Bars vs atmospheres
- Replies: 13
- Views: 307
Re: Bars vs atmospheres
They are both units of pressure; I think it depends on the question and what units that specific question wants you to use.
- Sun Jan 12, 2020 5:15 pm
- Forum: Ideal Gases
- Topic: Units of Pressure
- Replies: 8
- Views: 236
Re: Units of Pressure
I do not think we will be expected to memorize them as it will most likely be provided in a formula sheet but it is good to understand them!
- Sun Jan 12, 2020 5:12 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: changing conditions
- Replies: 6
- Views: 237
Re: changing conditions
As explained by Dr. Lavelle, a reaction tends to favor the side that has less substance to reach equilibrium. If we take away product, the reaction will favor the products in order to balance the products and reactants or reach equilibrium.
- Sun Jan 12, 2020 5:07 pm
- Forum: Ideal Gases
- Topic: PV = nRT
- Replies: 16
- Views: 1824
Re: PV = nRT
The P stands for pressure
V is volume
n is the number of moles
R is the ideal gas constant
and T is temperature.
V is volume
n is the number of moles
R is the ideal gas constant
and T is temperature.
- Sun Jan 12, 2020 5:03 pm
- Forum: Ideal Gases
- Topic: Topics on Test 1
- Replies: 37
- Views: 1255
Re: Topics on Test 1
Test 1 will probably consist of Outline 1 and Outline 2!
- Sun Dec 08, 2019 3:38 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3008737
Re: Post All Chemistry Jokes Here
I am definitely "(dien)" after that chemistry final!!!!
- Sun Dec 08, 2019 3:31 pm
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate Covalent Bond
- Replies: 8
- Views: 588
Re: Coordinate Covalent Bond
In a regular covalent bond, the atoms involved in the bonding share a pair of electrons. However, in a coordinate covalent bond, two electrons are contributed by a single atom.
- Sun Dec 08, 2019 3:27 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma Vs Pi
- Replies: 12
- Views: 758
Re: Sigma Vs Pi
Sigma bonds are stronger than pi bonds because sigma bonds head-on overlap while pi bonds overlap side by side. When there is one bond, that forms a sigma bond. When there are two bonds, there is one sigma bond and pi bond. When there are three bonds, there are 2pi bonds and one sigma bond.
- Sun Dec 08, 2019 3:20 pm
- Forum: Properties of Light
- Topic: Speed of Light
- Replies: 7
- Views: 604
Re: Speed of Light
The standard unit for speed of light is m / s. The units are also given in the constants sheet provided to us during finals/midterms.
- Sun Dec 08, 2019 3:17 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3008737
Re: Post All Chemistry Jokes Here
When you tell a chemistry joke and there are no reactions :(
- Fri Dec 06, 2019 12:16 pm
- Forum: Electronegativity
- Topic: Periodic Table Trend
- Replies: 40
- Views: 2237
Periodic Table Trend
What is the trend for electronegativity and ionization energy?
- Fri Dec 06, 2019 11:41 am
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate covalent bonds
- Replies: 9
- Views: 738
Re: Coordinate covalent bonds
I understand the coordinate covalent bonds are covalent bonds in which both electrons come from the same atom, but what does the necessarily mean? I do not quite understand what it is stating.
- Fri Dec 06, 2019 11:30 am
- Forum: Coordinate Covalent Bonds
- Topic: Hemoglobin and Myoglobin
- Replies: 1
- Views: 202
Hemoglobin and Myoglobin
What about hemoglobin and myoglobin do we need to know for the final?
- Fri Dec 06, 2019 11:28 am
- Forum: Dipole Moments
- Topic: Melting and Boiling Points
- Replies: 9
- Views: 657
Melting and Boiling Points
Can we assume that melting and boiling points will always be higher for hydrogen bonds than any other intermolecular force?
- Fri Dec 06, 2019 11:02 am
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 3
- Views: 326
Resonance
Can resonance structures determine the strength of an acid? Or is there no correlation between both?
- Fri Dec 06, 2019 10:14 am
- Forum: Trends in The Periodic Table
- Topic: Atomic Radius vs Ionic Radius
- Replies: 3
- Views: 388
Atomic Radius vs Ionic Radius
I know atomic radius and ionic radius both follow the same periodic trend but what is the difference between them?
- Wed Dec 04, 2019 8:36 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordinate Compounds
- Replies: 3
- Views: 234
Coordinate Compounds
What are some key concepts to know about coordinate compounds for the final?
- Mon Dec 02, 2019 5:48 pm
- Forum: Lewis Acids & Bases
- Topic: Definition
- Replies: 7
- Views: 535
Re: Definition
A Lewis acid is an electron-pair acceptor while a Lewis base is an electron-pair donor.
- Mon Dec 02, 2019 5:18 pm
- Forum: Conjugate Acids & Bases
- Topic: Water as an Acid/Base
- Replies: 20
- Views: 1441
Re: Water as an Acid/Base
Yes H2O is an amphoteric compound so it depends fully on what it is reacting with.
- Mon Dec 02, 2019 5:13 pm
- Forum: Biological Examples
- Topic: Chemotherapy
- Replies: 6
- Views: 430
Re: Chemotherapy
I think for class, we need to know mainly about Cisplatin, which binds to DNA to kill cancer cells.
- Mon Dec 02, 2019 4:26 pm
- Forum: Lewis Acids & Bases
- Topic: Long bonds vs Short bonds?
- Replies: 9
- Views: 876
Re: Long bonds vs Short bonds?
Since long bonds are farther away from the nuclei, it is easier to remove H+ so thus long bonds are strong acids. Conversely, short bonds are harder to break so they are weak acids.
- Mon Dec 02, 2019 4:19 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Class wed 11/27
- Replies: 7
- Views: 502
Re: Class wed 11/27
Lavelle went over neutralization and relative acidity. He also stated that an acidic solution's H3O+ is greater than OH- and the opposite occurs for basic solutions.
- Mon Dec 02, 2019 4:07 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: Ionization in Water
- Replies: 8
- Views: 1028
Re: Ionization in Water
Strong bases are completely ionized in water while weak bases are partially/incompletely ionized in water.
- Mon Dec 02, 2019 3:59 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis acid & Bronstead Acid
- Replies: 3
- Views: 184
Re: Lewis acid & Bronstead Acid
A Lewis acid is an electron acceptor while a Bronsted acid is a proton donor.
- Mon Dec 02, 2019 3:56 pm
- Forum: Lewis Acids & Bases
- Topic: Weak vs. Strong
- Replies: 8
- Views: 694
Re: Weak vs. Strong
Strong acids are completely ionized in water or solution while strong bases are completely ionized in solution. Weak acids and bases are partially dissociated in water/solution.
- Mon Dec 02, 2019 3:53 pm
- Forum: Amphoteric Compounds
- Topic: Identifying Amphoteric Compounds
- Replies: 5
- Views: 407
Re: Identifying Amphoteric Compounds
The one amphoteric compound we have gone over in lecture is H2O since it can act as a base and acid. I think it is sufficient enough to know that H2O is the main amphoteric compound.
- Sun Nov 24, 2019 8:25 pm
- Forum: Hybridization
- Topic: Hybrid orbitals
- Replies: 5
- Views: 313
Re: Hybrid orbitals
You always draw the Lewis structure first to determine the hybrid orbitals.
- Sun Nov 24, 2019 8:18 pm
- Forum: Dipole Moments
- Topic: Polar or nonpolar
- Replies: 8
- Views: 540
Re: Polar or nonpolar
O2 would be considered nonpolar since the bonds are evenly distributed and cancel out, thus there is no net dipole. We can also say that because they have the same electronegativity, there is never an electronegativity difference between them, therefore it is nonpolar.
- Sun Nov 24, 2019 8:14 pm
- Forum: Electronegativity
- Topic: Electronegativity
- Replies: 16
- Views: 993
Re: Electronegativity
The higher the electronegativity, the stronger the bond is and the shorter the bond length is. Since the electronegativity is higher, then the closer a bond becomes to being ionic rather than covalent.
- Sun Nov 24, 2019 8:10 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma and Pi Bonds
- Replies: 7
- Views: 409
Re: Sigma and Pi Bonds
A single bond is a sigma bond, while a pi bond occurs with double and triple bonds. For double bonds, there is one pi bond and sigma bond. For a triple bond, there is two sigma bonds and one pi bond.
- Sun Nov 24, 2019 8:08 pm
- Forum: Ionic & Covalent Bonds
- Topic: Hydrogen Bond Sites
- Replies: 5
- Views: 381
Re: Hydrogen Bond Sites
If an H bonds with a Fluorine, Nitrogen, or Oxygen, it is considered a hydrogen bond.
- Sun Nov 24, 2019 8:07 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordinate covalent bonds
- Replies: 5
- Views: 310
Re: Coordinate covalent bonds
A coordinate covalent bond is when one atom donates both electrons in a covalent bond.
- Sun Nov 24, 2019 8:00 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent Shape
- Replies: 31
- Views: 2836
Re: Bent Shape
A bent shape can have up to one or two lone pairs around the central atom.
- Sun Nov 17, 2019 8:26 pm
- Forum: Bond Lengths & Energies
- Topic: Electron Density
- Replies: 10
- Views: 616
Re: Electron Density
Yes, lone pairs are considered regions of electron density because they alter the molecular structure significantly. For example, a lone pair on a central atom can turn a trigonal planar into a trigonal pyramidal.
- Sun Nov 17, 2019 8:23 pm
- Forum: Bond Lengths & Energies
- Topic: Shorter bond lengths
- Replies: 12
- Views: 656
Re: Shorter bond lengths
The bond length between atoms with two or more bonds are shorter than those with single bonds. The more electrons, the stronger the pull is and the shorter the bond length is.
- Sun Nov 17, 2019 8:16 pm
- Forum: Bond Lengths & Energies
- Topic: Angle Distortion
- Replies: 4
- Views: 333
Re: Angle Distortion
We can tell when a VSEPR model has distortion because usually the central atom will have a lone pair or more. When the central atom has a lone pair, it pushes the bond electrons closer to one another, thereby making the bond angle smaller.
- Sun Nov 17, 2019 8:12 pm
- Forum: Dipole Moments
- Topic: Polarity
- Replies: 7
- Views: 407
Re: Polarity
For a molecule to be polar, it must possess a non-zero value of dipole moment. In the molecule CCl4, the bond polarity is canceled by the symmetric tetrahedral shape causing the dipole moment to be zero.
- Sun Nov 17, 2019 8:05 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Length
- Replies: 22
- Views: 1225
Re: Bond Length
The bond length is determined experimentally, so we do not determine the bond lengths ourselves.
- Sun Nov 03, 2019 10:29 pm
- Forum: Bond Lengths & Energies
- Topic: Why Are Double Bonds Shorter
- Replies: 16
- Views: 6045
Re: Why Are Double Bonds Shorter
Double bonds are shorter because the pull/attraction to the nucleus is greater than single bonds.
- Sun Nov 03, 2019 10:24 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Distorted Electrons
- Replies: 4
- Views: 264
Re: Distorted Electrons
What exactly are the characteristics of distorted electrons?
- Sun Nov 03, 2019 10:22 pm
- Forum: Electronegativity
- Topic: electronegativity trend
- Replies: 9
- Views: 635
Re: electronegativity trend
Electronegativity goes down the periodic table because as the electrons are farther away from the nucleus, there is decreased attraction thereby lessening the pull.
- Sun Nov 03, 2019 10:19 pm
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate Covalent Bonds
- Replies: 5
- Views: 1253
Coordinate Covalent Bonds
What is exactly the significance of coordinate covalent bonds and how does it help us understand bond structure in general?
- Sun Nov 03, 2019 10:17 pm
- Forum: Octet Exceptions
- Topic: Expanded Valence Shells
- Replies: 6
- Views: 171
Re: Expanded Valence Shells
Elements past the third period can have expanded valence shells due to the presence of a d-orbital.
- Sun Oct 27, 2019 2:32 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent bonds
- Replies: 5
- Views: 176
Re: Covalent bonds
Usually, covalent bonds are between two nonmetals and involves the sharing of electron pairs between atoms. There might be some exceptions to it, as the individual above stated but mainly, covalent bonds are between two nonmetals.
- Sun Oct 27, 2019 2:25 pm
- Forum: Lewis Structures
- Topic: Anion/Cations
- Replies: 2
- Views: 126
Anion/Cations
How exactly would I represent anions and cations in Lewis structures? Would these be implied by removing an electron from the Lewis structure if it is cation and adding an electron if it is an anion?
- Sun Oct 27, 2019 2:20 pm
- Forum: Lewis Structures
- Topic: Expanded Octet
- Replies: 6
- Views: 189
Re: Expanded Octet
It is stated that d-orbitals can carry more than 8e-. The examples that Dr. Lavelle gave in lecture were the elements, Chlorine, Phosphorus and Sulfur.
- Sun Oct 27, 2019 2:11 pm
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 8
- Views: 177
Resonance
Is the purpose of resonance structures to help us draw the best/most accurate Lewis Structure? I am still slightly confused on resonance and what the purpose of it is.
- Sun Oct 27, 2019 1:29 pm
- Forum: Lewis Structures
- Topic: Clarification
- Replies: 6
- Views: 200
Clarification
Can someone explain whether the octet rule is more important than obtaining a 0 formal charge or vice versa?