Search found 109 matches
- Fri Mar 13, 2020 8:33 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic vs Electrolytic cells
- Replies: 6
- Views: 567
Re: Galvanic vs Electrolytic cells
In an electrolytic cell, the set up is similar to the galvanic cell. However, the anode is not directly connected to the cathode. Instead, it is connected to an external power supply that drives the reaction.
- Fri Mar 13, 2020 8:31 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Dr. Lavelle's week 10 review - last question
- Replies: 3
- Views: 351
Re: Dr. Lavelle's week 10 review - last question
A couple of the TA's discussion reviews posted on Chemistry Community also review problems like this for additional assistance.
- Tue Mar 10, 2020 12:28 am
- Forum: Second Order Reactions
- Topic: Derivations of Reactions
- Replies: 5
- Views: 533
Re: Derivations of Reactions
I think the equations also appear on our formula sheet. It's always good to know how they are derived though, just in case.
- Tue Mar 10, 2020 12:27 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE table
- Replies: 5
- Views: 443
Re: ICE table
When the K value is less than 10-3, it is generally safe to estimate without the x. However, make sure to only exclude variables that are being added or subtracted. To make sure estimation was appropriate, make sure the percent dissociation is under 5%.
- Mon Mar 09, 2020 10:40 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n=2
- Replies: 7
- Views: 518
Re: n=2
N is the moles of electrons transferred. This is variable depending on the reaction, and can range from 1 and above.
- Mon Mar 09, 2020 10:38 pm
- Forum: Balancing Redox Reactions
- Topic: oxidation number
- Replies: 10
- Views: 788
Re: oxidation number
It is important to know that O has an oxidation number of 2- and H has an oxidation number of 1+. You are usually given the overall charge of a molecule. All the individual charges should add up to the overall charge. Thus, you can then solve for the unknown oxidation number.
- Mon Mar 09, 2020 10:33 pm
- Forum: Balancing Redox Reactions
- Topic: balancing reactions
- Replies: 6
- Views: 526
Re: balancing reactions
I believe there are some Khan Academy videos on how to balance redox reactions as well where he works through an example.
- Mon Mar 09, 2020 10:31 pm
- Forum: General Rate Laws
- Topic: Equations
- Replies: 5
- Views: 440
Re: Equations
While it could come up on the final, I don't think Dr. Lavelle has asked us in either 14A or 14B to derive any equations. I think they are provided on the formula sheet too.
- Mon Mar 09, 2020 10:30 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: midterm 6 b
- Replies: 6
- Views: 473
Re: midterm 6 b
The states of matter hint at the answer, as all the products and reactants in answer choice a are solids.
- Mon Mar 02, 2020 5:48 pm
- Forum: Balancing Redox Reactions
- Topic: Electrochemical series.
- Replies: 4
- Views: 381
Re: Electrochemical series.
Electrochemical series are redox couples arranged in order of oxidizing and reducing strengths. They are usually arranged with strong oxidizing agents at the top of the list and strong reducing agents at the bottom.
- Mon Mar 02, 2020 5:44 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L5 b.
- Replies: 3
- Views: 310
Re: 6L5 b.
I think he meant to say nonmetal, as the electrode must be both solid and metal.
- Mon Mar 02, 2020 5:41 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram for 6L.5(b)
- Replies: 2
- Views: 189
Re: Cell Diagram for 6L.5(b)
A TA mentioned that the cell diagrams could be written in the form s|g|aq||aq|g|s. So, I'm not sure why the textbook chose to write it otherwise. I think the TAs will not take off points if we stick to this structure on the exams.
- Mon Mar 02, 2020 5:36 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: instantaneous rate
- Replies: 16
- Views: 989
Re: instantaneous rate
The instantaneous rate is used because it refers to the rate at one specific time. In contrast, the average rate occurs over a longer time period, so it is not as precise.
- Mon Mar 02, 2020 5:33 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Order
- Replies: 5
- Views: 491
Re: Order
Reaction order is the power to which the concentration of a single substance is raised in a rate law.
- Mon Feb 24, 2020 4:41 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrolytic Cell
- Replies: 2
- Views: 253
Re: Electrolytic Cell
In an electrolytic cell, the set up is pretty similar to the galvanic cell. However, the anode is not directly connected to the cathode. Instead, it is connected to an external power supply that drives the reaction.
- Mon Feb 24, 2020 4:39 pm
- Forum: Student Social/Study Group
- Topic: 2/24 lecture
- Replies: 5
- Views: 444
Re: 2/24 lecture
We mainly discussed the Nernst equation, which is covered in section 6N of the textbook I think.
- Mon Feb 24, 2020 4:34 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff Equation
- Replies: 7
- Views: 558
Re: Van't Hoff Equation
Yes, I believe that the Van't Hoff equation could be on Test 2.
- Mon Feb 24, 2020 4:31 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: cis and trans entropy
- Replies: 3
- Views: 395
Re: cis and trans entropy
Trans is the opposite of cis in this case. While trans will be on different sides, cis will both be on the same side.
- Mon Feb 24, 2020 4:29 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: test 2 material clarification
- Replies: 10
- Views: 694
Re: test 2 material clarification
Yes, I believe that Gibbs free energy will be covered on Test 2. More specifically, the second set of problems on the Thermodyamics outline will be covered on Test 2.
- Mon Feb 17, 2020 12:59 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: G vs G knot
- Replies: 15
- Views: 1763
Re: G vs G knot
G naught is used for elements in their standard states under normal conditions. G is used for nonstandard conditions.
- Mon Feb 17, 2020 12:57 pm
- Forum: Biological Examples (*DNA Structural Transitions, etc.)
- Topic: Examples Expected to Know
- Replies: 15
- Views: 1903
Re: Examples Expected to Know
Although this is not a set list, the outlines for each topic sometimes mention specific biological examples to know. However, it is good to be familiar with anything that Dr. Lavelle mentions.
- Mon Feb 17, 2020 12:52 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidizing/Reducing Agents
- Replies: 11
- Views: 842
Re: Oxidizing/Reducing Agents
Oxidizing agents are a species that removes electrons from a species being oxidized (and is itself reduced) in a redox reaction. On the other hand, reducing agents are species that supplies electrons to a substance being reduced (and is itself being oxidized) in a redox reaction.
- Mon Feb 17, 2020 12:48 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Boltzmann Formula
- Replies: 11
- Views: 900
Re: Boltzmann Formula
W is referring to the degeneracy. W can be calculated by raising the number of different orientations/states by the number of atoms/molecules.
- Mon Feb 17, 2020 12:44 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: sign of delta G
- Replies: 9
- Views: 4488
Re: sign of delta G
When G=0, the reaction is at equilibrium.
- Tue Feb 11, 2020 12:46 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4D.5
- Replies: 1
- Views: 150
Re: 4D.5
I believe that the answer would be 7 kJ. To find the change in internal energy, use the equation delta U = q +w. You know that q = -15 kJ because q = delta H. If work is being done on a system, the work is positive. If work is done by a system, then work is negative. So, the equation would be delta ...
- Tue Feb 11, 2020 12:43 am
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm grading
- Replies: 8
- Views: 459
Re: Midterm grading
I think my TA from last quarter mentioned that each problem is graded by one TA, so the grading for each problem is uniform.
- Tue Feb 11, 2020 12:41 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: spontaneity
- Replies: 7
- Views: 407
Re: spontaneity
For part 2, I believe you can set the delta G equal to 0. Then solve the equation 0 = delta H - (delta S x T). By solving for T, you find the temperature for which the reaction becomes spontaneous.
- Tue Feb 11, 2020 12:38 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: delta U = q + w
- Replies: 3
- Views: 196
Re: delta U = q + w
Another way to think about it is in terms of exothermic and endothermic reactions. If the reaction is exothermic and is releasing heat, then the q will be negative. If the reaction is endothermic and absorbing energy, the q will be positive.
- Tue Feb 11, 2020 12:36 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: equations
- Replies: 2
- Views: 149
Re: equations
For the change in volume, the equation would be delta S = n x R x ln(V2/V1). From the formula sheet, it seems that the equation to calculate the positional/residual entropy is delta S = KB x ln (W).
- Mon Feb 03, 2020 6:28 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Specific heat capacity
- Replies: 7
- Views: 459
Re: Specific heat capacity
The only difference between the two is that specific heat capacity is per gram of the substance. On the other hand, molar heat capacity is simply measured per mole of the substance. Besides the difference in units, they measure the same thing.
- Mon Feb 03, 2020 6:26 pm
- Forum: Calculating Work of Expansion
- Topic: internal energy
- Replies: 4
- Views: 143
Re: internal energy
A state property is not dependent on path taken to obtain that state. Additionally, state properties can be added and subtracted. This is all true for delta U.
- Mon Feb 03, 2020 6:22 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: Midterm Review
- Replies: 7
- Views: 425
Re: Midterm Review
At least for last quarter, he posted the midterm review on Chemistry Community a couple days before the midterm review session. As of now, I don't think it is up yet.
- Mon Feb 03, 2020 6:20 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Midterm
- Replies: 8
- Views: 344
Re: Midterm
The midterm takes place in the middle of Week 6. However, the review sessions for the midterm started today and extend up until the midterm.
- Mon Feb 03, 2020 6:19 pm
- Forum: General Science Questions
- Topic: Test 1: Sig Figs
- Replies: 7
- Views: 404
Re: Test 1: Sig Figs
I think that I would err on the side of caution and be mindful of sig figs. Additionally, my TA mentioned that using the correct units was something they focus on as well.
- Tue Jan 28, 2020 10:06 am
- Forum: Phase Changes & Related Calculations
- Topic: State Functions
- Replies: 9
- Views: 501
Re: State Functions
A state function is a property of a substance that is independent of how the sample was prepared. According to the textbook definition, it seems that enthalpy is listed as a state function.
- Tue Jan 28, 2020 10:03 am
- Forum: Administrative Questions and Class Announcements
- Topic: Grading of Tests
- Replies: 18
- Views: 789
Re: Grading of Tests
Test #1 may come back this week or next week most likely, depending on when the TAs grade them. In 14A, they usually were returned outside of lecture or during the discussion section.
- Tue Jan 28, 2020 10:01 am
- Forum: General Science Questions
- Topic: Extra Credit
- Replies: 19
- Views: 867
Re: Extra Credit
There was no extra credit opportunities in 14A, so I assume there would be no extra credit opportunities in 14B as the grading and assignments seem to be the same format.
- Tue Jan 28, 2020 9:59 am
- Forum: Administrative Questions and Class Announcements
- Topic: homework for week 4
- Replies: 11
- Views: 435
Re: homework for week 4
Usually the outlines are listed in the order we complete them on the website. So, I think doing anything from outline three, Thermochemistry, would be acceptable.
- Tue Jan 28, 2020 9:58 am
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy and Heat
- Replies: 6
- Views: 227
Re: Enthalpy and Heat
According to the textbook, enthalpy is a state property; a change in enthalpy is equal to the heat transferred at constant pressure. Heat on the other hand is the energy that is transferred as the result of a temperature difference between a system and its surroundings.
- Tue Jan 21, 2020 9:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5J.5 D
- Replies: 5
- Views: 237
Re: 5J.5 D
The answer would be no change. This is due to the fact that there are an equal number of moles of gas on both sides of the reaction equation. Thus, an increase in pressure will not affect the equilibrium.
- Tue Jan 21, 2020 9:13 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ice box approximation
- Replies: 9
- Views: 352
Re: ice box approximation
Approximation is okay when the K value is less than 10^-3. To check if your approximation was appropriate at the end of the problem, you can calculate the percent ionization. If this percent is less than 5%, approximation was acceptable.
- Tue Jan 21, 2020 9:10 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Calculator
- Replies: 4
- Views: 194
Re: Calculator
Since this calculator is non-programmable, I think it would be acceptable for all the exams.
- Tue Jan 21, 2020 9:08 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: H20 in the ICE table
- Replies: 26
- Views: 1549
Re: H20 in the ICE table
Typically in the textbook problems, water is seen in liquid form. Since liquid and solids are not included in ice tables, do not include water. However if water was in gas form and depending on the problem, I think you might have to include it.
- Tue Jan 21, 2020 9:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Discussion
- Replies: 8
- Views: 311
Re: Discussion
Discussions are not graded on attendance, as the TAs do not take roll. However, handing in homework can be thought of as a participation/attendance grade that we do turn in during discussion.
- Mon Jan 13, 2020 4:14 pm
- Forum: Ideal Gases
- Topic: When to use this equation
- Replies: 14
- Views: 503
Re: When to use this equation
You would use this equation to convert between partial pressure and concentration. If you were asked specifically for Kp or Kc and given the opposite units, you would use this equation.
- Mon Jan 13, 2020 4:06 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5I.27
- Replies: 8
- Views: 444
Re: 5I.27
The equilibrium composition is referring to the concentration of each product and reactant provided in the chemical equation. An ICE table could be helpful in this kind of question.
- Mon Jan 13, 2020 4:04 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 5J.3
- Replies: 5
- Views: 225
Re: 5J.3
When NO is removed, the product of the forward reaction is being decreased. In order to reach equilibrium again, the forward reaction will proceed and use the reactants to make more product. So, the reactants, including NH3, decrease as a result.
- Mon Jan 13, 2020 4:01 pm
- Forum: Student Social/Study Group
- Topic: F19 Final
- Replies: 4
- Views: 186
Re: F19 Final
In an email Dr. Lavelle sent out last quarter, it said that finals exams would be available during the 3rd week of Winter quarter at 3034 Young Hall.
- Mon Jan 13, 2020 3:59 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 5J.1
- Replies: 3
- Views: 234
Re: 5J.1
In equilibrium, the rate of reaction for the products and reactants are the same. When increasing one of the reactants, more products must be formed to balance out the increase in reactants, which will preserve the equilibrium. So, the H2 concentration will increase.
- Mon Jan 06, 2020 8:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constant
- Replies: 4
- Views: 132
Re: Equilibrium Constant
I think a large K is considered to be greater than 10^3 and a small K is considered to be less than 10^-3
- Mon Jan 06, 2020 8:23 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G.3
- Replies: 8
- Views: 555
Re: 5G.3
Since both parts a and b consist of only molecules in the gas phase, partial pressures are used throughout instead of concentrations. So, when solving for the K value, you would be solving for the Kp value more specifically.
- Mon Jan 06, 2020 8:20 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: H3O and OH
- Replies: 5
- Views: 201
Re: H3O and OH
I think they should be included, as they are not a solid, liquid, or solvent.
- Mon Jan 06, 2020 8:18 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium constant v. Reaction quotient
- Replies: 3
- Views: 181
Re: Equilibrium constant v. Reaction quotient
Both are found using the same equation, but they differ because the reaction quotient is not specifically limited to equilibrium.
- Mon Jan 06, 2020 8:14 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Self Test 5G.3A
- Replies: 4
- Views: 158
Re: Self Test 5G.3A
Dr. Lavelle hasn't mentioned anything yet about using the ionic equations, so I think it might be a strategy specific to this problem/problems like it.
- Mon Dec 02, 2019 2:44 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acid strength
- Replies: 2
- Views: 177
Acid strength
I was confused in lecture today when learning that CH2FCOOH was a stronger acid than CH2ClCOOH because F is more electronegative than Cl. However, we also learned that HF was a weaker acid than HCl because it is lower on the periodic table and has a longer bond I think. These trends seem to contradi...
- Mon Dec 02, 2019 2:38 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: 6C.17
- Replies: 2
- Views: 267
Re: 6C.17
I would say that hypobromite is the stronger base. The justification might be due to electronegativity of the elements making up the molecule. In general, Br and O seem to be more electronegative than C H N and O.
- Mon Dec 02, 2019 2:34 pm
- Forum: Properties of Light
- Topic: Visible Light Spectrum
- Replies: 3
- Views: 348
Re: Visible Light Spectrum
I agree that the most important part to memorize is probably that the visible light spectrum ranges from 400 nm (violet)-700 nm (red).
- Mon Dec 02, 2019 2:32 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration
- Replies: 8
- Views: 771
Re: Electron Configuration
I think we are supposed to write them as 3D, 4S because it is then easier to see where the electron is being removed from in ions.
- Mon Dec 02, 2019 2:31 pm
- Forum: Conjugate Acids & Bases
- Topic: Ligands
- Replies: 12
- Views: 681
Re: Ligands
All ligands are Lewis bases and the central atom would be the Lewis acid.
- Sat Nov 30, 2019 10:19 am
- Forum: General Science Questions
- Topic: test taking nervousness
- Replies: 19
- Views: 1130
Re: test taking nervousness
Getting in the right mindset to take finals can be tough. I think not cramming right before the test is important and instead just relaxing could be helpful. Maybe set-up practice exams for yourself where you have the same materials/time you do for the final. I hope you find what works well for you :)
- Sat Nov 30, 2019 10:16 am
- Forum: Resonance Structures
- Topic: What is a Resonance "Structure"
- Replies: 12
- Views: 1066
Re: What is a Resonance "Structure"
According to the textbook, resonance is a blending of Lewis structures into a single composite, hybrid structure. Additionally, a resonance hybrid is the composite structure that results from resonance.
- Sat Nov 30, 2019 10:11 am
- Forum: Student Social/Study Group
- Topic: Preparing for the final
- Replies: 25
- Views: 1316
Re: Preparing for the final
I think the best way to review would to do a mix of everything suggested. I think going to review sessions, study groups, youtube videos, and a lot of practice problems are all great review for the final. I think the more comfortable you are with the concept, the better off you will be for the final.
- Sat Nov 30, 2019 10:08 am
- Forum: Lewis Acids & Bases
- Topic: HCl vs HF
- Replies: 19
- Views: 1422
Re: HCl vs HF
HCl is a stronger acid because it is lower on the periodic table, indicating that it is less electronegative and larger. This makes it easier to dissociate, making it a stronger acid. HF for this reason is often not considered a strong acid.
- Sat Nov 30, 2019 10:06 am
- Forum: Lewis Acids & Bases
- Topic: Proton acceptor and proton donor?
- Replies: 33
- Views: 2223
Re: Proton acceptor and proton donor?
The ones that donate protons are acids. The ones that accept these protons are bases.
- Mon Nov 25, 2019 2:24 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: polydentate
- Replies: 3
- Views: 288
Re: polydentate
A polydentate ligand is simply a ligand that can attach at several binding sites
- Mon Nov 25, 2019 2:21 pm
- Forum: Lewis Acids & Bases
- Topic: Strong Acids
- Replies: 8
- Views: 614
Re: Strong Acids
As the textbook mentions all of these as strong acids, I would try to remember that they are all strong acids. Additionally, I think it is important to know not only that they are all strong acids, but also what makes them all strong acids.
- Mon Nov 25, 2019 12:05 pm
- Forum: Naming
- Topic: Correct naming conventions
- Replies: 5
- Views: 332
Re: Correct naming conventions
You would use the suffix ate if the complex has an overall negative charge. The suffix is added to the end of the metal.
- Mon Nov 25, 2019 12:02 pm
- Forum: Naming
- Topic: Di-, Tri-, Tetra- vs Bis-, Tris-, Tetrakis-
- Replies: 11
- Views: 1007
Re: Di-, Tri-, Tetra- vs Bis-, Tris-, Tetrakis-
The prefixes bis-, tris-, and tetrakis- are used when a ligand already has a Greek prefix or the ligand is polydentate.
- Mon Nov 25, 2019 11:58 am
- Forum: Naming
- Topic: Roman numerals
- Replies: 6
- Views: 400
Re: Roman numerals
According to the textbook, an oxidation number is "the effective charge on an atom in a compound, calculated according to a set of rules (see Toolbox K.1). An increase in oxidation number corresponds to oxidation; a decrease corresponds to reduction."
- Tue Nov 19, 2019 8:55 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Difference between Electorn arrangement and VSEPR
- Replies: 1
- Views: 201
Re: Difference between Electorn arrangement and VSEPR
Finding the electorn configuration refers to the distribution of electrons into different energy levels (such as 1s2 2s2 2p4). The VSEPR model is about finding the geometry of molecules based on the interactions of the electrons (arrangement of electron density). The shapes of tetrahedral and trigon...
- Tue Nov 19, 2019 8:47 pm
- Forum: Bond Lengths & Energies
- Topic: Boiling Point
- Replies: 7
- Views: 1950
Re: Boiling Point
SiF4 would have a higher boiling point than SIH4 even though their Lewis structures look similar. This is due to the fact that Fluorine has a larger mass, which indicates more electrons than Hydrogen. Thus, it is more polarizable and has stronger intermolecular forces.
- Tue Nov 19, 2019 8:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E: Question 29
- Replies: 3
- Views: 240
Re: 2E: Question 29
Yes, option 1 has the largest dipole moment because the two dipoles are closer together and are separated by a smaller angle. An easy way to think about this is to think to imagine that if the dipoles were on opposite sides, they would be more likely to cancel out and would not be as strong of a dip...
- Tue Nov 19, 2019 8:37 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: formal charge
- Replies: 6
- Views: 537
Re: formal charge
First you should look at the periodic table and determine how many valence electrons that the element should have. Next, count the total electrons present in the form of both lone pairs and bonds. Then compare this to the ideal number of valence electrons that the element should have. If there are m...
- Tue Nov 19, 2019 8:33 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-Dipole
- Replies: 5
- Views: 313
Re: Dipole-Dipole
In the case of CO2 for example, the dipoles created by the Carbon and Oxygen are both pointing towards the central Carbon, they would cancel each other out and there would be no dipole moment. CO2 is nonpolar in this example.
- Wed Nov 13, 2019 11:38 am
- Forum: Ionic & Covalent Bonds
- Topic: covalent bonds
- Replies: 7
- Views: 482
Re: covalent bonds
There are 3. A coordinate covalent bond according to the textbook is a bond formed between a Lewis base and a Lewis acid by sharing an electron pair originally belonging to the Lewis base. A polar covalent bond is a covalent bond between atoms that have partial electric charges. A nonpolar covalent ...
- Wed Nov 13, 2019 11:36 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: intermolecular forces
- Replies: 8
- Views: 593
Re: intermolecular forces
A good example to think of is a water molecule. There is a great difference in electronegativity between the Oxygen and Hydrogen, so the molecule is not balanced in a way. So you know the water molecule is a dipole.
- Wed Nov 13, 2019 11:33 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: London Forces and Dipole-Dipole
- Replies: 5
- Views: 368
Re: London Forces and Dipole-Dipole
Yes, London forces act on all molecules. It does not matter if they are polar or nonpolar, or ionic or covalent.
- Wed Nov 13, 2019 11:27 am
- Forum: Dipole Moments
- Topic: Intermolecular Forces
- Replies: 6
- Views: 341
Re: Intermolecular Forces
CHI3 has a higher boiling point because on the periodic table, Iodine is on a lower period than Fluorine. Following the periodic trends, this indicates that iodine has a larger size. With this larger size, Iodine can have stronger induced dipoles.
- Wed Nov 13, 2019 11:21 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: Intermolecular forces
- Replies: 10
- Views: 725
Re: Intermolecular forces
According to the textbook, a London interaction is the interaction between instantaneous electric dipoles on neighboring molecules. Van der Waals interactions are Intermolecular interactions that depend on the inverse sixth power of the separation.
- Fri Nov 08, 2019 11:17 am
- Forum: Balancing Chemical Reactions
- Topic: Balancing This Equation
- Replies: 11
- Views: 1192
Re: Balancing This Equation
An important step to remember is that combustion always involves Oxygen gas as a reactant, even though it is often not states in the problem. So always remember to add Oxygen gas to the chemical equation of a combustion reaction before balancing, and you should be good.
- Fri Nov 08, 2019 11:13 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: intermolecular/intramolecular forces
- Replies: 1
- Views: 140
Re: intermolecular/intramolecular forces
Intramolecular forces refer to the forces that hold atoms within the molecule together. On the other hand, intermolecular forces are referring to the forces between different molecules.
- Fri Nov 08, 2019 11:10 am
- Forum: Octet Exceptions
- Topic: elements in 3p block
- Replies: 8
- Views: 568
Re: elements in 3p block
Elements in the 3p block actually can have a 3d orbital, but the orbital does not have to be completely filled in the case of some elements.
- Fri Nov 08, 2019 11:08 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarisability vs Polarizing Power
- Replies: 15
- Views: 1181
Re: Polarisability vs Polarizing Power
According to the textbook, polarizing power is the ability of an ion to polarize a neighboring atom or ion. On the other hand, polarizability is a measure of the ease with which the electron cloud of a molecule can be distorted.
- Tue Nov 05, 2019 1:03 am
- Forum: Properties of Electrons
- Topic: Electron affinity
- Replies: 3
- Views: 293
Re: Electron affinity
According to the textbook, electron affinity is the energy released when an electron is added to a gas-phase atom or monatomic ion. Electronegativity is the ability of an atom to attract electrons to itself when it is part of a compound. I think just knowing the periodic trends should be a good start.
- Tue Oct 29, 2019 7:38 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: What is the x, y, z?
- Replies: 4
- Views: 1512
Re: What is the x, y, z?
The x, y, and z refer to different orbitals in the p subshell. The x, y, and z are just three variables used to represent the three different subshells.
- Tue Oct 29, 2019 7:32 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal change equation
- Replies: 3
- Views: 178
Re: Formal change equation
I don't think the formula charge equation will be provided on the front page of our test along with the equations and constants. I think it may be beneficial to memorize it either way.
- Tue Oct 29, 2019 7:27 pm
- Forum: Electronegativity
- Topic: Electronegativity
- Replies: 11
- Views: 635
Re: Electronegativity
Electronegativity is the ability of an atom to attract electrons to itself when it is part of a compound. I think electronegativity decreases down a group and increases across a period.
- Tue Oct 29, 2019 7:18 pm
- Forum: Electronegativity
- Topic: Is there a relationship between ionization energy and electronegativity?
- Replies: 2
- Views: 140
Re: Is there a relationship between ionization energy and electronegativity?
Ionization energy and electronegativity are related in the sense that they generally follow similar trends on the periodic table. Ionization energy and electronegativity both tend to be lower in the bottom left corner and higher in the top right corner.
- Mon Oct 28, 2019 9:49 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration of Tungsten
- Replies: 2
- Views: 716
Re: Electron Configuration of Tungsten
Yes, the s orbital will get filled first, then the d orbital, then the p orbital. It is important to note that the s orbital that gets filled first is one period higher than the d orbital (4s will get filled before 3d).
- Tue Oct 22, 2019 9:38 pm
- Forum: Trends in The Periodic Table
- Topic: 1F. 21
- Replies: 2
- Views: 156
Re: 1F. 21
I think it's better to err on the side of caution and say yes. Antimony is a metalloid and cadmium is a metal. This can be deduced from which block on the periodic table the element is in.
- Tue Oct 22, 2019 9:32 pm
- Forum: DeBroglie Equation
- Topic: When to use the DeBroglie Equation
- Replies: 3
- Views: 134
When to use the DeBroglie Equation
Under what situations am I supposed to use the DeBroglie equation? When should I use this equation instead of other equations to find wavelength (like c= lambda x v)?
- Tue Oct 22, 2019 9:28 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: 1D.13 "The 6d- subshell"
- Replies: 4
- Views: 264
Re: 1D.13 "The 6d- subshell"
Don't get hung up on the 6 for this question. Instead just focus on the d-orbital, which as you stated has 5 m values. The 6 just indicates how many other shells there are in addition.
- Tue Oct 22, 2019 9:23 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Atomic radius vs. Ionic radius
- Replies: 5
- Views: 285
Atomic radius vs. Ionic radius
I was just wondering what the difference between an atomic radius and ionic radius is. Do they follow the same periodic table trends?
- Tue Oct 22, 2019 9:21 pm
- Forum: *Particle in a Box
- Topic: cations and anions
- Replies: 5
- Views: 1064
Re: cations and anions
An anion is a negatively charged ion. On the other hand, a cation is a positively charged ion. I think when you have a neutral atom and it either loses or gains an atom (which creates a cation or anion), the radius either decreases or increases respectively.
- Wed Oct 16, 2019 2:39 pm
- Forum: Properties of Light
- Topic: Lyman Series & Balmer Series
- Replies: 4
- Views: 240
Re: Lyman Series & Balmer Series
The difference is in the energy level that he electron rests at. The Lyman series involves the ground state, which is when n=1. On the other hand, Balmer series corresponds to n=2.
- Wed Oct 16, 2019 2:28 pm
- Forum: SI Units, Unit Conversions
- Topic: Use of Angstrom?
- Replies: 3
- Views: 315
Re: Use of Angstrom?
I think that the use of angstroms will just depend on the unit we are in. While it could come up in any question, it seems like angstroms won't occur as frequently in this Quantum unit as some other units, such as out chemical bonds unit. As long as you know how to convert with angstroms, you should...
- Wed Oct 16, 2019 2:23 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: 1D 11
- Replies: 4
- Views: 317
Re: 1D 11
Just remember that the values of m and l are related. The values of m range from l, l-1, ..., -l. When asking about orbitals, you want to think about the m value. So if l =0, you can only have one orbital. If l=1, you can have 3 orbitals. When l=2, you can have 5 orbitals. When l=3, you can have 7 o...
- Wed Oct 16, 2019 2:19 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal plane for s-orbitals?
- Replies: 3
- Views: 213
Nodal plane for s-orbitals?
Today in lecture, it was mentioned that p,d, and f -orbitals all have nodal planes. Why do s-orbitals not have nodal planes?
- Wed Oct 16, 2019 2:14 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: What is Molarity?
- Replies: 11
- Views: 1063
Re: What is Molarity?
Molarity is simply just the concentration of solution that is expressed as the number of moles of solute/ the number of liters in the solution. Molarity is used frequently in the textbook during dilution problems and often uses the formula:
Molarity = mols of solute/Liters of solution.
Molarity = mols of solute/Liters of solution.
- Thu Oct 10, 2019 4:22 pm
- Forum: Balancing Chemical Reactions
- Topic: compound state in chem rxn
- Replies: 3
- Views: 329
Re: compound state in chem rxn
What I've noticed in the textbook problems is that they generally give you the state of matter, especially when the compound is not very common. Usually reading the context clues for the problem will hint at the state of matter as well.