Search found 111 matches
- Sat Mar 13, 2021 8:49 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Temperature change effect on rate constant
- Replies: 3
- Views: 450
Re: Temperature change effect on rate constant
Adding on, a good thing to remember is the higher the activation energy is, the more dependent K is on temperature.
- Sat Mar 13, 2021 8:48 pm
- Forum: First Order Reactions
- Topic: textbook 7B #5
- Replies: 3
- Views: 401
Re: textbook 7B #5
The way you solved it is correct. I would double check units.
- Sat Mar 13, 2021 8:40 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Calculating n
- Replies: 17
- Views: 1064
Re: Calculating n
After balancing the half-reactions, whatever the number of electrons is that get transferred from the oxidation reaction to the reduction reaction is n.
- Sat Mar 13, 2021 8:23 pm
- Forum: *Enzyme Kinetics
- Topic: zero order half-life plots
- Replies: 1
- Views: 253
Re: zero order half-life plots
Because the axis is half live vs. concentration, and we know that the relationship in a zero order reaction for half life is [A]/2k, we know that as the concentration decreases, the half life will decrease as well. The relationship is directly related, not exponentially, so the graph would be linear...
- Sat Mar 13, 2021 8:18 pm
- Forum: *Enzyme Kinetics
- Topic: intermediates vs. catalysts
- Replies: 31
- Views: 1511
Re: intermediates vs. catalysts
Intermediates go from being a product of a previous step to a reactant in future steps. Catalysts start in the reactants and do not change and end up on the product side as well. Both cancel out but remember to check whether it is being used as a reactant or whether it's simply staying unchanged.
- Sun Mar 07, 2021 9:10 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Slowest step
- Replies: 38
- Views: 1713
Re: Slowest step
The way I like to think of it is that your team is only as good as your slowest player. So, even if three other people ran extremely fast, the majority of the time would be taken up by the slowest leg. So the rate at which your team ran is basically dependent and mostly accounted for by the slowest ...
- Sun Mar 07, 2021 9:06 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidizing atoms in a molecule
- Replies: 7
- Views: 445
Re: Oxidizing atoms in a molecule
If the atom within a molecule gets reduced or oxidized, then the oxidation state of the molecule would also have to change, so the molecule too would be considered either reduced or oxidized.
- Sun Mar 07, 2021 8:48 pm
- Forum: First Order Reactions
- Topic: Equation Confusion
- Replies: 16
- Views: 753
Re: Equation Confusion
The first equation is for zero order and the second equation is for first order reactions.
- Sun Mar 07, 2021 8:44 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Texbook 6M.13
- Replies: 4
- Views: 355
Re: Texbook 6M.13
Appendix 2B, which is linked in many textbook problems online has every half-reaction that appears in textbook problems.
- Sun Mar 07, 2021 8:43 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: E° vs. E and G° vs. G
- Replies: 25
- Views: 1106
Re: E° vs. E and G° vs. G
Yes, the little circle means at standard conditions! Another thing to remember is that E naught and G naught are values that are static, as in they do not change even when the current conditions of the reaction change.
- Sun Feb 28, 2021 7:46 pm
- Forum: Balancing Redox Reactions
- Topic: hw #18
- Replies: 3
- Views: 233
Re: hw #18
I had this same issue and it's a sapling formatting issue. Don't put parenthesis around your product and your answer should be correct.
- Sun Feb 28, 2021 7:43 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Textbook 5G.11, Q vs K
- Replies: 4
- Views: 448
Re: Textbook 5G.11, Q vs K
Reaction quotients don't include solids and liquids and BCl3 is the only one in the gas phase so Q would equal 1/BCl3^s
- Sun Feb 28, 2021 7:38 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Writing cell diagrams
- Replies: 3
- Views: 255
Writing cell diagrams
In some text book problems, the cell diagrams include H+ (aq), but don't include H2O (l). When do we include H+ when writing cell diagrams? And why do we exclude water?
- Sun Feb 28, 2021 7:35 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling week 7/8 #5
- Replies: 7
- Views: 952
Re: Sapling week 7/8 #5
I had the same question as you and I got the same answer and it was correct. Maybe try rearranging the order of the products, because my products were listed PbO2 + Cl- + H2O + 2OH-
- Sun Feb 28, 2021 7:31 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Reactions
- Replies: 22
- Views: 1217
Re: Balancing Reactions
I don't think the order matters, but I remember one of the sapling questions marked me wrong for switching the order of two of the reactants so maybe there is some rule?
- Sun Feb 21, 2021 8:27 pm
- Forum: Student Social/Study Group
- Topic: Post Midterm 2 De-stressing
- Replies: 92
- Views: 8713
Re: Post Midterm 2 De-stressing
305405193 wrote:Is Wanda Vision that good? I LOVE MARVEL so I've been debating on seeing it, but everyone says its so GOODD. Please let me know if it's worth skipping studying time LOL
Literally go binge it rn. It's so good
- Sun Feb 21, 2021 8:24 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Boiling point
- Replies: 9
- Views: 731
Re: Boiling point
Phase changes occur at equilibrium because all the energy is used for changing the states rather than heating up the compounds.
- Sun Feb 21, 2021 8:22 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: entropy positive value
- Replies: 30
- Views: 2060
Re: entropy positive value
I think he was referring to the second law, which states that an isolated system's entropy will always increase over time. A system can have a negative change in entropy, but overall somewhere in the universe, the entropy will increase.
- Sun Feb 21, 2021 8:19 pm
- Forum: Balancing Redox Reactions
- Topic: Salt Bridge Clarification
- Replies: 3
- Views: 230
Re: Salt Bridge Clarification
Salt bridges allow ions to go from the cathode solution to the anode solution to counter the increasing negative charge on the cathode side. If salt bridges didn't exist, the transfer of electrons would eventually stop. I'm not sure how exactly they move, but the driving force behind it may just be ...
- Sun Feb 21, 2021 8:13 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Different Standard Reduction Potentials
- Replies: 2
- Views: 208
Re: Different Standard Reduction Potentials
Don't quote me on this but I think it has to do with how well a compound acts as an oxidizing agent, or how likely it is to be reduced. That explains why Flourine gas (fluorine has very good electron pulling power), has such a high standard potential.
- Sun Feb 21, 2021 8:06 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Stable vs Unstable Gibbs Free Energy
- Replies: 16
- Views: 2613
Re: Stable vs Unstable Gibbs Free Energy
If a compound is thermodynamically stable, then forming it would be thermodynamically spontaneous in terms of Gibbs free energy. Therefore, A negative Gibbs free energy for the formation of some compound indicates that it is stable. If the Gibbs free energy is positive, then it's unstable.
- Sun Feb 14, 2021 9:16 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Homework Problem 4F.7
- Replies: 1
- Views: 154
Re: Homework Problem 4F.7
For both parts a and b, you'll use the equation deltaS = nCln(T2/T1). The difference between the two parts will be due to different heat capacity values, C. For the constant pressure, the heat capacity of a monatomic gas is (3/2)R, and for constant volume, the heat capacity is (5/2)R, where R is the...
- Sun Feb 14, 2021 9:06 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: isometric and enthalpy
- Replies: 3
- Views: 359
Re: isometric and enthalpy
I think another thing to remember is that in a situation with constant volume, the heat, q, is equal to the change in internal energy. Also, when there is no change in volume, gases do no work, so that's why the work term gets removed from deltaU = q + w
- Sun Feb 14, 2021 9:02 pm
- Forum: Student Social/Study Group
- Topic: Fav Shows of the Moment
- Replies: 115
- Views: 56607
Re: Fav Shows of the Moment
Nathan Lao 2I wrote:Wandavision is literally so good. I just don't like how each episode is a cliffhanger. They answer our questions about the previous episode but then introduce way more at the end of each one. The suspense kills me.
I get more and more confused the more episodes I watch
- Sun Feb 14, 2021 9:01 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Sapling #6
- Replies: 6
- Views: 394
Re: Sapling #6
Basically, you have to find the change in entropy due to volume and then combine it with the change in entropy due to temperature change. Use nRln(v2/v1) and nCln(T2/T1) and then add the two together.
- Sun Feb 14, 2021 8:58 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase Changes: delta H and delta S
- Replies: 5
- Views: 669
Re: Phase Changes: delta H and delta S
When you have a phase change, for example going from a solid to a liquid, delta H is positive because heat is going into the system to make this phase change happen. Going from a solid to a liquid is also a more disordered state, and therefore delta S would have to be positive.
- Sun Feb 14, 2021 8:56 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: qrev vs q
- Replies: 21
- Views: 2077
Re: qrev vs q
qrev is heat from a reversible expansion/compression, but q is just a heat term. Make sure that you use qrev when solving for entropy changes.
- Sun Feb 07, 2021 7:56 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Can heat capacities be negative?
- Replies: 52
- Views: 14345
Re: Can heat capacities be negative?
Heat capacities talk about how much heat a system needs to gain, and thus will always be positive. However, when you have a loss of heat (negative q) that's usually because delta T is negative.
- Sun Feb 07, 2021 7:55 pm
- Forum: Student Social/Study Group
- Topic: Midterm 2 study tips
- Replies: 26
- Views: 1518
Re: Midterm 2 study tips
Do the textbook problems, they are your friends. I haven't gone to any UA workshops, but I've heard they're good practice. Also, I like reading over the outlines to make sure I know all of the bullet points.
- Sun Feb 07, 2021 7:51 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: HW 14
- Replies: 13
- Views: 1714
Re: HW 14
Yeprem wrote:but for V in PV=nRT which V value do i use, V1 or V2?
Use V1, because the number of moles won't change when you expand a gas.
- Sun Feb 07, 2021 7:45 pm
- Forum: Student Social/Study Group
- Topic: Superbowl Sunday
- Replies: 26
- Views: 1869
Re: Superbowl Sunday
this did not age well
- Sun Feb 07, 2021 7:44 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: converting T to kelvin
- Replies: 46
- Views: 3716
Re: converting T to kelvin
The best thing to do to be safe would be to check the units of whatever it is you're trying to solve or the gas constant given in the problem. Also, if you are using the change in temperature then celsius and kelvins are interchangeable because a change of +1 degrees celsius is the same as a change ...
- Sun Feb 07, 2021 7:42 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Combustion = Exothermic
- Replies: 23
- Views: 943
Re: Combustion = Exothermic
When you form the bonds to make water and carbon dioxide, that releases more energy than it takes to break the bonds in the reactants. Also, think of combustion as producing heat, so you know that it's "releasing" heat, and would therefore be exothermic.
- Sun Feb 07, 2021 7:40 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling Week 3/4 #13
- Replies: 8
- Views: 517
Re: Sapling Week 3/4 #13
At constant pressure, work done by the system will be -delta n *RT. Therefore, for a system to DO work, the change in n would have to be a positive number, so the reaction should produce a greater number of moles of gas compared to the moles of gas used. For the equation A(s) + B(s) -> C(g), the del...
- Sun Jan 31, 2021 9:43 pm
- Forum: Phase Changes & Related Calculations
- Topic: State Property
- Replies: 11
- Views: 566
Re: State Property
Heat depends on the path taken, so it's not a state function. However, enthalpy is.
- Sun Jan 31, 2021 7:21 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Sapling #8 Weeks 3&4
- Replies: 10
- Views: 550
Re: Sapling #8 Weeks 3&4
The delta H given in the problem refers to the KJ per mole of S8. Therefore multiple the delta H with the number of moles of S8 (1.31).
- Sun Jan 31, 2021 7:13 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Molar Heat Capacity
- Replies: 11
- Views: 379
Re: Molar Heat Capacity
You'll probably use it in some practice problems, if they give you moles of a substance and molar heat capacity. Otherwise, we usually use specific heat.
- Sun Jan 31, 2021 7:12 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: delta H vs delta U
- Replies: 11
- Views: 562
Re: delta H vs delta U
Delta H is the change in heat energy whereas delta U is the change in total energy
- Sun Jan 31, 2021 7:09 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calculus for thermochemistry
- Replies: 5
- Views: 387
Re: Calculus for thermochemistry
Maybe some upper divisions have calculus pre-reqs but I'm not sure.
- Sun Jan 31, 2021 7:06 pm
- Forum: Phase Changes & Related Calculations
- Topic: Vapor vs gas
- Replies: 121
- Views: 14821
Re: Vapor vs gas
Yes! Vapors are gases.
- Sun Jan 24, 2021 9:28 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Q9
- Replies: 2
- Views: 93
Re: Sapling Q9
If pH<pKa, then it is in a more acidic environment. This means that the species will act as a base and will then accept a proton. Therefore in the solution, there is more HA present. If pH>pKa, then it's in a basic environment. This means that the species will act as an acid and donate its proton. T...
- Sun Jan 24, 2021 9:20 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling #2 Week 2
- Replies: 5
- Views: 263
Re: Sapling #2 Week 2
You'll have to test the assumption. So when you do your ice tables and solve for x (assuming that x is negligible in the denominator), then take x and divide it by the concentration of the initial solution. If this is greater than 5% then the assumption doesn't work and you have to use quadratic. To...
- Sun Jan 24, 2021 8:37 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: pKa
- Replies: 14
- Views: 550
Re: pKa
They both equal each other.
- Sun Jan 24, 2021 8:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: derive pKW = pH + pOH [ENDORSED]
- Replies: 3
- Views: 435
Re: derive pKW = pH + pOH [ENDORSED]
I'm pretty sure that's all you need to know because that is how you derive that equation.
- Sun Jan 24, 2021 8:24 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: acids and bases
- Replies: 4
- Views: 296
Re: acids and bases
Acids generally have a carboxyl group or an acidic hydrogen. If a compound is a group 1 hydroxide, or a group 1/2 oxide, it is a base. When you have salt compounds, what I usually do is split the compound into two ions. If the compound is strong, its conjugate acid/base will be weak so the solution ...
- Sun Jan 17, 2021 7:38 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: 5% rule
- Replies: 5
- Views: 290
Re: 5% rule
I would always plug it in to check if it's less than 5% because it really depends on the concentration of the initial solution. That's why I trust the 10^-4 limit rather than 10^-3.
- Sun Jan 17, 2021 7:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs Kc
- Replies: 9
- Views: 478
Re: K vs Kc
Correct me if I'm wrong, but I believe that Kc is just a more specific way to describe K. However, if you want to convert between Kc and Kp, then I think the equation is Kp= Kc(RT)^delta(n), where delta n is the change in the number of moles (moles of products - moles of reactants). So calculating ...
- Sun Jan 17, 2021 4:43 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Sapling Week 1 #6
- Replies: 7
- Views: 582
Re: Sapling Week 1 #6
So what you do is write the equation for Q, which is the same as Kc but the concentrations aren't equilibrium concentrations. So, Q = ([NH3]^2) / ([H2]^3 * [N2])
Then, just plug in the concentrations that they gave in the problem.
Then, just plug in the concentrations that they gave in the problem.
- Sun Jan 17, 2021 4:38 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 1 #10
- Replies: 3
- Views: 212
Re: Sapling Week 1 #10
Since the problem gives you the equilibrium concentrations already, all you need to do is write the equation for Kc which would be Kc = [NO2]^2 / [N2O4]. The NO2 is squared because one mol of N2O4 yields two moles of NO2. Then just plug in the values.
- Sun Jan 17, 2021 4:31 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: How do we know a compound is a weak acid or base?
- Replies: 6
- Views: 413
Re: How do we know a compound is a weak acid or base?
For the problems in 6D, when they give you a compound, what I usually do is split the compound into two ions. For example, 6D.15 asks to find the pH of 0.19M NH4Cl. So looking at this compound you need to figure out whether its acidic or basic so you know whether to use Ka or Kb when solving for the...
- Sun Jan 10, 2021 7:04 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling #7
- Replies: 3
- Views: 206
Re: Sapling #7
Because the question says "immediately after the temperature change", the concentrations of the reactants or products haven't changed yet so Q is the same. However, because the reaction is endothermic, increasing the temperature will increase K (favoring the products).
- Sun Jan 10, 2021 5:59 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs Kc
- Replies: 9
- Views: 478
Re: K vs Kc
Correct me if I'm wrong, but I believe that Kc is just a more specific way to describe K. However, if you want to convert between Kc and Kp, then I think the equation is Kp= Kc(RT)^delta(n), where delta n is the change in the number of moles (moles of products - moles of reactants).
- Sun Jan 10, 2021 5:56 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 51.13c
- Replies: 4
- Views: 153
Re: 51.13c
Large equilibrium constants favor products, and a small equilibrium constant favors the reactants. At 1000K, F2 has a larger equilibrium constant than Cl2 (you'll probably solve for this in parts a and b). A large equilibrium constant in this example would favor the products of dissociation, therefo...
- Sun Jan 10, 2021 5:54 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Stable Reactants and Products
- Replies: 7
- Views: 252
Re: Stable Reactants and Products
Large equilibrium constants favor products, and a small equilibrium constant favors the reactants. As an example, think about the dissociation of F2 and Cl2. At 1000K, F2 has a larger equilibrium constant than Cl2. A large equilibrium constant in this example would favor the products of dissociation...
- Sun Jan 10, 2021 5:47 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling hw 5
- Replies: 14
- Views: 570
Re: Sapling hw 5
You want to use equations that, when added together, give you the overall reaction. Sometimes, you'll have to flip one of the equations (use 1/K) or you may have to multiply all of the reactants and products of an equation by some constant (use K^constant). When you alter the individual equations, r...
- Tue Dec 15, 2020 10:13 pm
- Forum: Conjugate Acids & Bases
- Topic: conjugate acids and bases
- Replies: 8
- Views: 549
Re: conjugate acids and bases
The conjugate acid will gain a H+ (add 1 to the charge), and the conjugate base will lose a H+ (subtract 1 from the charge).
- Tue Dec 15, 2020 10:09 pm
- Forum: Coordinate Covalent Bonds
- Topic: Polydentate Ligands
- Replies: 8
- Views: 513
Re: Polydentate Ligands
I would look for lone pairs on the lewis structure and then determine whether those pairs are in a favorable orientation, like with spacers. That's the only way to bind to the same central metal.
- Tue Dec 15, 2020 10:01 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Why is CO (carbon monoxide) monodentate?
- Replies: 6
- Views: 1682
Re: Why is CO (carbon monoxide) monodentate?
The structure doesn't have spacers making it impossible for two lone pairs to become bonding pairs simultaneously. It would try and bend the bond.
- Tue Dec 15, 2020 9:59 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: How do you determine the stronger base/acid?
- Replies: 7
- Views: 562
Re: How do you determine the stronger base/acid?
I would memorize the seven strong acids, because that rules out all the other acids as weak. For the relative strengths of the weaker acids it depends on the acid type: 1) binary acids are some HA acid, where A is some anion. With these acids, the strength increases as the electron affinity of A inc...
- Tue Dec 15, 2020 9:52 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation #s help
- Replies: 5
- Views: 421
Re: Oxidation #s help
To reiterate what others have said, you take the charge of the element that interacts with the complex ion (which is what is in brackets). The total charge of the compound should be zero, so you know that the charge on the element(s) outside of the brackets should equal the negative of the total cha...
Re: -ate
-ate is used when the complex ion has a negative charge. Usually, the coordination compound will contain some metal cation in front of the complex ion in the bracket.
- Sun Dec 06, 2020 6:45 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate Ligands We Have to Know
- Replies: 3
- Views: 204
Re: Polydentate Ligands We Have to Know
I believe that oxalato, en, edta, dien, and carbonato are generally the ones we need to know as they come up in textbook problems. I haven't encountered any other ones.
- Sun Dec 06, 2020 6:44 pm
- Forum: Hybridization
- Topic: Clarification on Hybridization
- Replies: 2
- Views: 90
Re: Clarification on Hybridization
The regions of electron density should equal the orbitals that are available from the hybridizations. sp = 2 orbitals, so, therefore, two regions of electron density. sp3 = 4 orbitals, so therefore four regions of electron density.
- Sun Dec 06, 2020 6:32 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Pka and Ka
- Replies: 6
- Views: 383
Re: Pka and Ka
Ka is the acid dissociation constant and pKa is the negative log of the Ka value.
- Sun Dec 06, 2020 6:30 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Number and Regions of density
- Replies: 8
- Views: 811
Re: Coordination Number and Regions of density
Coordination numbers refer to the number of bonds between the central metal and ligands. Regions of density could include lone pairs of electrons which does not pertain to coordination numbers.
- Sun Dec 06, 2020 6:28 pm
- Forum: Naming
- Topic: Anion Naming
- Replies: 7
- Views: 422
Re: Anion Naming
Yes! Only prefixes that specify the number of ligand molecules is used. Anything outside of the bracket that pertains to the complex ion doesn't use a prefix.
- Sun Nov 29, 2020 11:59 pm
- Forum: Ionic & Covalent Bonds
- Topic: Polar and Nonpolar
- Replies: 37
- Views: 2007
Re: Polar and Nonpolar
The shape of the molecule can show whether dipoles are positioned to cancel each other out.
- Sun Nov 29, 2020 5:37 pm
- Forum: Limiting Reactant Calculations
- Topic: Combustion
- Replies: 10
- Views: 633
Re: Combustion
Oxygen gas can be assumed in excess during combustion reactions unless stated otherwise.
- Sun Nov 29, 2020 5:31 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Textbook Problem 2E27
- Replies: 4
- Views: 152
Re: Textbook Problem 2E27
Since we will most likely be provided the molecular formal of compounds that we are unfamiliar with, you can probably search it up and still get good practice from doing the lewis structure. The past two midterms have always given us the molecular formulas so I wouldn't worry about it too much.
- Sun Nov 29, 2020 5:30 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Textbook Problem 2F3
- Replies: 4
- Views: 266
Re: Textbook Problem 2F3
After drawing the Lewis structure, the first bonds (single) between any two atoms would be sigma bonds and any additional bonds between the atoms (making it a double or triple bond) would be pi bonds.
- Sun Nov 29, 2020 5:28 pm
- Forum: Limiting Reactant Calculations
- Topic: Cl vs Cl2
- Replies: 9
- Views: 7421
Re: Cl vs Cl2
Chlorine and Oxygen gas are both diatomic molecules and will be written Cl2 and O2.
- Sun Nov 29, 2020 5:26 pm
- Forum: Sigma & Pi Bonds
- Topic: Sapling Q #16
- Replies: 14
- Views: 951
Re: Sapling Q #16
Molecules with resonance structures where the double or triple bond can be moved among different atoms consist of pi bonds, so depending on the lewis structures and whether resonance is possible, that can show whether the bonds are delocalized.
- Sun Nov 22, 2020 8:49 pm
- Forum: Lewis Structures
- Topic: Electron Density
- Replies: 14
- Views: 675
Re: Electron Density
Electron density is the probability of finding an electron in a given region of an orbital. Greater electron density can indicate the more negative pole of a molecule.
- Sun Nov 22, 2020 7:01 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: CH3F Molecular Shape
- Replies: 7
- Views: 2090
Re: CH3F Molecular Shape
CH3F is tetrahedral and I believe that the bond angles will decrease by a small amount.
- Sun Nov 22, 2020 6:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 21
- Views: 805
Re: Bond Angles
To reiterate what others have said since bond angles are experimentally determined, I would remember the angles for the parent shapes where all bond angles are equal and then when larger areas of electron density are present then the bond angles would decrease.
- Sun Nov 22, 2020 6:31 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Shape
- Replies: 10
- Views: 464
Re: Shape
I believe it would be linear.
- Sun Nov 22, 2020 6:29 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Finding negative pole of a molecule
- Replies: 4
- Views: 379
Re: Finding negative pole of a molecule
The best way would be to compare electronegativities and whichever atom has the greater electronegativity (electron pulling power) would be the negative end of the pole. The relative differences in electronegativity would also tell us which ones have a greater dipole moment (greater difference in el...
- Sun Nov 15, 2020 4:06 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Energy Levels in electron configurations
- Replies: 5
- Views: 166
Re: Energy Levels in electron configurations
So basically the 4s subshell gets filled first before 3d. This is because, at the time where there are no electrons in the 3d subshell, the 4s subshell is lower in energy. However, once the 3d subshell starts getting filled, it has lower energy than the 4s subshell and therefore gets written before...
- Sun Nov 15, 2020 4:04 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Sapling week 5 & 6 #5
- Replies: 20
- Views: 879
Re: Sapling week 5 & 6 #5
The formal charge on the carbon is a -2.
- Sun Nov 15, 2020 4:03 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Atomic orbitals + probability
- Replies: 1
- Views: 105
Re: Atomic orbitals + probability
I think we just need to know that orbitals aren't pre-existing but rather describe the probabilities of finding electrons at a specific energy level.
- Sun Nov 15, 2020 4:00 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Textbook Question
- Replies: 3
- Views: 159
Re: Formal Charge Textbook Question
Make sure you're using the pdf solutions of the textbook that's in the sapling website. It might just be an error in the solutions in the back of the ebook because in the pdf, the left structure is the favored one because of the minimized formal charges.
- Sun Nov 15, 2020 3:58 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Scandium Exception
- Replies: 1
- Views: 192
Re: Scandium Exception
Yes, as soon as the 3d subshell starts getting filled, it is written before the 4s subshell because it is at a lower energy level.
- Sun Nov 15, 2020 3:56 pm
- Forum: Student Social/Study Group
- Topic: Favorite TV shows
- Replies: 277
- Views: 50782
Re: Favorite TV shows
GOSSIP GIRL !!!
and as soon as you finish start YOU
and as soon as you finish start YOU
- Sun Nov 15, 2020 3:55 pm
- Forum: Resonance Structures
- Topic: lewis base or acid
- Replies: 15
- Views: 531
Re: lewis base or acid
A lewis acid accpets electrons and therefore is usually a cation, a molecule where the central atom is electron deficient, or a molecule with polar double bonds. A lewis base donates the electrons and therefore is usually an anion, a molecule where atoms have excess electrons or a molecule with lone...
- Sun Nov 15, 2020 3:53 pm
- Forum: Ionic & Covalent Bonds
- Topic: Polarity of bonds vs molecules
- Replies: 6
- Views: 220
Re: Polarity of bonds vs molecules
The ability for a molecule to be non-polar yet consist of polar bonds is due to the ability for dipoles to cancel out. This can be seen after looking at the shape of the molecule (for example, a symmetrical molecule will most likely have dipoles that cancel each other out).
- Sun Nov 08, 2020 6:25 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Energy Levels in electron configurations
- Replies: 5
- Views: 166
Re: Energy Levels in electron configurations
So basically the 4s subshell gets filled first before 3d. This is because, at the time where there are no electrons in the 3d subshell, the 4s subshell is lower in energy. However, once the 3d subshell starts getting filled, it has lower energy than the 4s subshell and therefore gets written before ...
- Sun Nov 08, 2020 6:23 pm
- Forum: Trends in The Periodic Table
- Topic: Elements that form Cations
- Replies: 6
- Views: 287
Re: Elements that form Cations
Electrons on the left side of the periodic table are more likely to form cations because of their low ionization energies and low electron affinities. They are more likely to lose their outermost electron as it isn't held as tightly by nuclear charge.
- Sun Nov 08, 2020 6:20 pm
- Forum: Ionic & Covalent Bonds
- Topic: Sapling #1
- Replies: 3
- Views: 214
Re: Sapling #1
Your structure seems right to me. Did the question ask to put formal charges?
- Sun Nov 08, 2020 6:18 pm
- Forum: Lewis Structures
- Topic: Sapling Week 5/6 HW #9
- Replies: 2
- Views: 113
Re: Sapling Week 5/6 HW #9
I think since the total formal charge of the ion is -1, it is considered more stable as opposed to a different lewis structure in which the oxygens would be given a formal charge value that isn't one even though they are more electronegative. I think when comparing lewis structures to see which is m...
- Mon Nov 02, 2020 8:52 pm
- Forum: Trends in The Periodic Table
- Topic: Sizes of ions vs elements
- Replies: 4
- Views: 228
Sizes of ions vs elements
How is it that Na+ is smaller than Cl-, but elemental Na is larger than elemental Cl?
- Sun Nov 01, 2020 8:24 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Determining Quantum Numbers
- Replies: 5
- Views: 306
Re: Determining Quantum Numbers
So the first three quantum numbers specify an orbital. Each orbital can hold a maximum of 2 electrons. So the first three quantum numbers can specify at most 2 electrons. Once the fourth quantum number is given, then the four numbers specify a single electron.
Hope this helps :)
Hope this helps :)
- Sun Nov 01, 2020 8:22 pm
- Forum: Photoelectric Effect
- Topic: sapling problem
- Replies: 2
- Views: 321
Re: sapling problem
Someone had asked this a couple weeks ago and this was my reasoning: So the problem gives the energy requried to remove an electron. In this problem, the work function should equal the energy of the incoming photon, so hv= work function. Substitute frequency for c/lamda so that you can solve for wav...
- Sun Nov 01, 2020 8:19 pm
- Forum: *Shrodinger Equation
- Topic: Schrodinger Equation
- Replies: 1
- Views: 198
Re: Schrodinger Equation
I'm not 100% sure but I believe we just need to understand it conceptually and what it represents because it helps explain quantum numbers in orbitals, but I don't think we need to do calculations with wave functions because in the textbook many of the problems required integration.
- Sun Nov 01, 2020 8:18 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Quantum Number Memorizing tips
- Replies: 2
- Views: 639
Re: Quantum Number Memorizing tips
For the quantum number l that specifies the subshell, you should probably just memorize that s = 0, p=1, and so on. For the Magnetic quantum number that gives you the specific orbital, i would remember that it depends on what l is : l, l-1, ...., -l
- Sun Nov 01, 2020 8:14 pm
- Forum: DeBroglie Equation
- Topic: average wavelength
- Replies: 3
- Views: 259
Re: average wavelength
Use deBroglie's wavelength equation where wavelength = h/p, and p is momentum. p=mv. The problem gives you the velocity of the particle so all you have to do is plug it into the equation.
- Sun Nov 01, 2020 8:12 pm
- Forum: Photoelectric Effect
- Topic: Participation points
- Replies: 16
- Views: 815
Re: Participation points
As long as the five posts are timestamped before 11:59pm of Sunday of every week, then you'll get the credit for all the posts.
- Sat Oct 24, 2020 5:54 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Question about the Delta X and what it stands for
- Replies: 6
- Views: 554
Re: Question about the Delta X and what it stands for
Delta X refers to uncertainty in position. In a problem where they say that the electron is bound by an atom, the uncertainty of the position would be the length of the atom because the electron could be anywhere in that range. If the problem said something like the uncertainty was 10 nm +/- 2nm, th...
- Sat Oct 24, 2020 5:49 pm
- Forum: Properties of Electrons
- Topic: Schrodinger's wave equation
- Replies: 4
- Views: 274
Re: Schrodinger's wave equation
The mathematical representation of wave functions from Schrodinger's wave equation are essentially math models of specific orbitals. So each orbital has a unique wave function that specifically works for that orbital. So yes, it could be used as a form of identification, but I'm not too sure that it...
- Sat Oct 24, 2020 5:44 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Textbook 1B.28
- Replies: 1
- Views: 138
Textbook 1B.28
Hi guys :) So this is an even numbered problem from the textbook. I know how to do part a, but I'm confused on part b and c, specifically on the mass of the Li+ atom. The uncertainty principle has negligible consequences for macroscopic objects. However, the properties of nanoparticles, which have d...
- Sat Oct 24, 2020 5:32 pm
- Forum: Photoelectric Effect
- Topic: Wavelength in Photoelectric Effect
- Replies: 7
- Views: 382
Re: Wavelength in Photoelectric Effect
It depends on the surface metal that has the electrons. Some metals require a greater frequency than others., so there's no exact range.