Search found 112 matches
- Thu Mar 11, 2021 6:51 pm
- Forum: General Rate Laws
- Topic: Sapling W9/W10 #5
- Replies: 5
- Views: 387
Re: Sapling W9/W10 #5
you just want to plug in the factors of how they are changing in the rate law equation. Since it is rate=k[A][B]^2, you can see that if A was halved it would be A/2 and that if B was tripled it would be [3B]^2 which would be 9B and therefore 9/2 would be by how much the rate increases
- Thu Mar 11, 2021 6:48 pm
- Forum: General Rate Laws
- Topic: Elementary Rate Laws
- Replies: 3
- Views: 312
Re: Elementary Rate Laws
yes! you would omit solids and liquids because their concentration basically stays the same
- Thu Mar 11, 2021 6:47 pm
- Forum: General Rate Laws
- Topic: Intermediate
- Replies: 59
- Views: 3883
Re: Intermediate
an intermediate is a molecule produced in the middle of the reaction but is later consumed before the final products are created
- Thu Mar 11, 2021 6:41 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Sapling #17
- Replies: 3
- Views: 221
Re: Sapling #17
another thing to note that since deltaH is positive, it is endothermic and you know that the activation energy of the forward reaction will be greater than the activation energy of the reverse. You can then evaluate your units from there
- Thu Mar 11, 2021 6:34 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: sapling week 10 #20
- Replies: 3
- Views: 362
Re: sapling week 10 #20
Here you would set up the equation Kcat/Kuncat=Ae^-Ea/RT of the catalyzed a=/Ae^-Ea/RT of the uncatalyzed and then plug in the values to get the answer
- Sat Mar 06, 2021 6:46 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Kinetic stability
- Replies: 14
- Views: 735
Re: Kinetic stability
kinetic stability refers to the energy barrier. There is more stability if the energy barrier is really large because then even if the reaction is favorable, it will be extremely small and therefore will not occur for a very long time. This can be seen with diamonds turning into graphite
- Sat Mar 06, 2021 6:41 pm
- Forum: Zero Order Reactions
- Topic: Half life
- Replies: 20
- Views: 1039
Re: Half life
[A]o/2K =t(1/2) is the equation and this shows that the half life of a zero order reaction is dependent on the initial concentration of A
- Sat Mar 06, 2021 6:27 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: First - Order/Order
- Replies: 7
- Views: 492
Re: First - Order/Order
order refers to the number of reactants that can form the product. first order is one reactant and so on
- Sat Mar 06, 2021 6:25 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Diamond vs. Graphite
- Replies: 23
- Views: 1127
Re: Diamond vs. Graphite
it is possible but because of that energy barrier it will take a very long time for that process to happen. You would need a catalyst to speed of the process but it is spontaneous
- Sat Mar 06, 2021 6:11 pm
- Forum: General Rate Laws
- Topic: Factors Affecting k
- Replies: 83
- Views: 5707
Re: Factors Affecting k
yes! It can only change when the temperature changes
- Sun Feb 28, 2021 5:28 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling #10
- Replies: 6
- Views: 306
Re: Sapling #10
The one with the highest reduction potential is likely to be more easily reduced and that makes it the best oxidizing agent
- Sat Feb 27, 2021 7:31 pm
- Forum: Balancing Redox Reactions
- Topic: sapling week 7/8 #5
- Replies: 1
- Views: 134
sapling week 7/8 #5
How would i balance this equation given that its a basic solution?
N2H4(g)+ClO−3(aq)⟶NO(g)+Cl−(aq)
N2H4(g)+ClO−3(aq)⟶NO(g)+Cl−(aq)
- Sat Feb 27, 2021 6:39 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Sapling #12 Week 7/8
- Replies: 4
- Views: 372
Re: Sapling #12 Week 7/8
also make sure to convert to kj because F is given in terms of joules but the answer wants it in Kj
- Sat Feb 27, 2021 6:19 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: sapling week 7/8 #12
- Replies: 3
- Views: 218
Re: sapling week 7/8 #12
I'm so confused on why I keep getting this wrong. I found that E for the anode is 2(1.498) and the cathode is 3(0.76) and it would end up with Ecell=.716 . Is this correct?
- Fri Feb 26, 2021 5:02 pm
- Forum: Balancing Redox Reactions
- Topic: sapling week 7/8 #3
- Replies: 2
- Views: 198
sapling week 7/8 #3
For a particular redox reaction, BrO− is oxidized to BrO−3 and Cu2+ is reduced to Cu+ . Complete and balance the equation for this reaction in basic solution. The phases are optional. So I am really confused on how to balance the acidity and add in H20 and OH- in the equations... can someone please ...
- Sun Feb 21, 2021 7:55 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrode vs. Anode
- Replies: 6
- Views: 337
Re: Electrode vs. Anode
An electrode is like a more general term that includes both the anode and cathode. The cathode is the positive charged side and anode is the negative charged side.
- Sun Feb 21, 2021 7:53 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: State function?
- Replies: 36
- Views: 1465
Re: State function?
it is not a state function because it depends on the path taken. Usually a state function will have delta in its equation
- Sun Feb 21, 2021 7:50 pm
- Forum: Balancing Redox Reactions
- Topic: Manipulating Reduction Potentials
- Replies: 5
- Views: 417
Re: Manipulating Reduction Potentials
because the reduction potential depends on the amount of electrons lost or gained rather than the moles of the reaction, it wouldn't change.
- Sun Feb 21, 2021 7:39 pm
- Forum: Calculating Work of Expansion
- Topic: Spontaneous
- Replies: 26
- Views: 1583
Re: Spontaneous
a reaction is spontaneous when it can occur by itself. It can be either exo or endothermic and all depends on if deltaG is negative
- Sun Feb 21, 2021 7:38 pm
- Forum: Van't Hoff Equation
- Topic: Sapling #18
- Replies: 12
- Views: 721
Re: Sapling #18
raise it to the power of e!
- Sat Feb 13, 2021 6:33 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Sapling #14
- Replies: 6
- Views: 287
Re: Sapling #14
try converting it into kelvin or maybe what happened is you didn't convert between j and kj
- Sat Feb 13, 2021 5:12 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Sapling number 8
- Replies: 7
- Views: 566
Re: Sapling number 8
you would have to break apart each change in entropy into sections. From there you can add them together and get the answer.
- Sat Feb 13, 2021 4:37 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: sapling week 5/6 assignment #15
- Replies: 6
- Views: 454
Re: sapling week 5/6 assignment #15
you would use the hess method. reverse the sign so that it goes from c to d and make sure your units are aligned but yes it is very similar to the enthaply questions we learned for the last midterm
- Sat Feb 13, 2021 4:11 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: W5/6 Sapling #6
- Replies: 6
- Views: 520
Re: W5/6 Sapling #6
Just be sure you take into account the moles that are given in the problem! At first I assumed n was 1 and that Cvm was the same and kept getting an incorrect number and then it was correct when I account for n
- Sat Feb 13, 2021 4:04 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: deltaS equations
- Replies: 8
- Views: 366
Re: deltaS equations
Hi! So in this case you would use delta s=q/t when the temp and volume are constant, delta s = Cvln(t2/t1) when the temperature is changing and the volume is constant (or just not measured) and delta s=nRln(v2/v1) when there is a change in volume but the temperature is constant
- Fri Feb 05, 2021 2:27 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Extensive vs intensive property for heat capacities
- Replies: 7
- Views: 345
Re: Extensive vs intensive property for heat capacities
extensive properties depend on the amount of substance/matter present or being measured while intensive properties do not
- Fri Feb 05, 2021 2:22 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: sapling week 3/4 question 15
- Replies: 4
- Views: 254
Re: sapling week 3/4 question 15
isn't the equation already balanced though? What kind of stoichiometry do you mean? Sorry I am just kind of confused how I can convert it from solid to gas in this equation
- Fri Feb 05, 2021 2:19 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling Question Week 3/4
- Replies: 4
- Views: 176
Re: Sapling Question Week 3/4
you can only assume w=0 when both the volume and pressure are constant. In this case you would need to use the ideal gas law to find the change in volume and then calculate w=-pdeltav
- Fri Feb 05, 2021 2:17 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling Week 3/4 #20
- Replies: 5
- Views: 260
Re: Sapling Week 3/4 #20
Yes so this just talks about the way the molecules are arranged. If it is linear, then the degree bond angles are 180 degrees and there is no polarity. It's like a review from chem14A
- Fri Feb 05, 2021 2:16 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: sapling week 3/4 #19
- Replies: 1
- Views: 120
sapling week 3/4 #19
Hi! I'm having trouble on this question. Honestly I have no clue where to start. I know how to find q but the second experiment is throwing me off a bit
- Fri Feb 05, 2021 2:00 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: sapling week 3/4 question 15
- Replies: 4
- Views: 254
sapling week 3/4 question 15
Hi! I've tried to solve this question and still continue to get the wrong answer... someone pls help :)!! Ok so I need to Calculate the value of work, w, for the system if 39.2 g NaN3 reacts completely at 1.00 atm and 22 ∘ C. and I am given the equation 2NaN3(s)⟶2Na(s)+3N2(g) So from here I know tha...
- Sun Jan 31, 2021 9:56 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Stable Form in Enthalpies of Formation
- Replies: 11
- Views: 521
Re: Stable Form in Enthalpies of Formation
i think you just memorize them. They have to be pure elements.
- Sun Jan 31, 2021 9:52 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: steam causing burns
- Replies: 40
- Views: 1413
Re: steam causing burns
this is because it is releasing heat not only as it is slowly becoming cooler but also in its phase change. It releases a lot of heat as it goes from gas to liquid
- Sun Jan 31, 2021 9:49 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: 534
Re: Sapling #8 Weeks 3&4
well we assume that the equation that was given is with 1 moles of s8 and when you are given more than that, like 1.21 moles, you would multiply the enthalpy by the amount of moles that are given
- Sun Jan 31, 2021 9:43 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Sapling Week 3/4 #6
- Replies: 14
- Views: 586
Re: Sapling Week 3/4 #6
well here you can tell combustion is involved because the products are CO2 and H2O and the reactant has O2
- Sun Jan 31, 2021 9:40 pm
- Forum: Phase Changes & Related Calculations
- Topic: Define Phase Change
- Replies: 78
- Views: 5531
Re: Define Phase Change
a phase change is just when a substance, like water, changes its state of matter and we try to find how much heat must be put in or taken out to allow that chnage to occur.
- Thu Jan 21, 2021 5:10 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Polyprotic Acids
- Replies: 8
- Views: 363
Re: Polyprotic Acids
i don't think there is a specific cut off but we need to know and assume that the second reaction will be way weaker and the K value will be extremely small
- Thu Jan 21, 2021 5:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: How to fill in 2nd row of ICE table?
- Replies: 25
- Views: 899
Re: How to fill in 2nd row of ICE table?
generally, we are given the initial concentration of one of the reactants which means that initially the products start with 0. From there, you know that in order for both products and reactants to exist, the reaction must happen and therefore some of the concentration of the reactants will have to ...
- Thu Jan 21, 2021 5:05 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Week 2 Sapling #5
- Replies: 9
- Views: 279
Re: Week 2 Sapling #5
in this case, I would not approximate the x value because you'll end up with a weird solution. keep x^2/M-x. M is what the initial concentration is and that is what we are trying to find. We can find x by using the pH and from there you can plug in X to find M.
- Thu Jan 21, 2021 5:03 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE table values
- Replies: 20
- Views: 923
Re: ICE table values
depends on what you are given. They should generally be in that but for example, if it given in bar, then use that.
- Thu Jan 21, 2021 5:02 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Sapling #9
- Replies: 7
- Views: 364
Re: Sapling #9
here you are comparing the concentration of HA and A-. A- is the charged form and HA is the neutral form. In this case, you want to make a ratio of how much of these products exist... and knowing that the solution will try to go to of a pH of 7 to stabilize and in that case they will try to take out...
- Thu Jan 21, 2021 4:59 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Sapling Week 2, Question 3
- Replies: 4
- Views: 216
Re: Sapling Week 2, Question 3
since the K value is not less than 10^-4, the approximation is not accurate enough so you would have to use the K formula and go the long way of using the quadratic formula to find a more accurate answer. It should be less than 9%
- Sun Jan 17, 2021 4:17 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: X less than 5 percent
- Replies: 11
- Views: 943
Re: X less than 5 percent
hello! I think this is why we have the 5% rule in place so that if it is over the 5% mark, it is better to use the quadratic equation because the approximation isn't as accurate
- Sun Jan 17, 2021 4:15 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Endothermic/exothermic reactions and K
- Replies: 11
- Views: 585
Re: Endothermic/exothermic reactions and K
Hi! So K will change because the change in temperature has an affect on the equilibrium constant. If the delta H is positive (endothermic reaction) and heat is added, it will cause K to increase because it will favor products being made since an increase in heat will favor the forward reaction. If d...
- Sun Jan 17, 2021 4:10 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Help on #7 Sapling Homework
- Replies: 5
- Views: 177
Re: Help on #7 Sapling Homework
we don't count Na+ as something that changes the pH because it comes from a strong base and since it fully dissociates, it will not affect the pH. Anything that dissociates from a weak base/acid will always affect the pH so we only put that into the ICE table
- Sun Jan 17, 2021 4:04 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q > K, Q< K
- Replies: 25
- Views: 862
Re: Q > K, Q< K
when Q>K, there are more products than there should be and therefore the reaction will shift towards the reactants so that the Q can balance out to equal K. When Q<K, there are more reactants than there should be which is why the quotient is not equal to K so the reaction will shift towards and favo...
- Sun Jan 17, 2021 4:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Week 1 Sapling 3
- Replies: 11
- Views: 498
Re: Week 1 Sapling 3
yes! Then make sure you set up the equation in a quadratic equation where you can then use the quadratic formula
- Sun Jan 17, 2021 3:58 pm
- Forum: Ideal Gases
- Topic: Equilibrium Constant (Q and K)
- Replies: 13
- Views: 668
Re: Equilibrium Constant (Q and K)
Hi! So Q is the reaction quotient and it can be used at any time of the reaction, while K is used when the reaction is at equilibrium. If Q is not equal to K, then we can predict what way the reaction will go until K and Q are the same.
- Sat Jan 09, 2021 6:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 1 #4
- Replies: 4
- Views: 180
Re: Sapling Week 1 #4
ok but how do you figure out x from here?
- Sat Jan 09, 2021 5:29 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Conceptual Understanding of Decrease in Volume
- Replies: 3
- Views: 134
Re: Conceptual Understanding of Decrease in Volume
in the problem that Lavelle showed us in the lecture, the effect of the decrease in volume caused the Q to not be equal to the K and from there, you will see a shift in products and reactant concentrations so that K can be equal to Q
- Sat Jan 09, 2021 5:25 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Impacts of Increasing Pressure
- Replies: 4
- Views: 161
Re: Impacts of Increasing Pressure
the pressure can really only increase if there is a change in the volume because unless you take the moles of solute out, they shouldn't change. Therefore, you can infer that volume has to change in order for pressure to change and that will cause the concentration to change as well.
- Sat Jan 09, 2021 5:23 pm
- Forum: Ideal Gases
- Topic: value of R
- Replies: 24
- Views: 1077
Re: value of R
it depends on the units given! Each R value uses different kinds of units so be extra sure to use the right R value and to pay close attention to the units given in the problem
- Sat Jan 09, 2021 5:21 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling week 1 #2
- Replies: 1
- Views: 76
Sapling week 1 #2
Hi! the question isP: 2SO(3)=>2SO(2)+O(2) and you are given that At a certain temperature, 0.980 mol SO3 is placed in a 4.00 L container and that at equilibrium, 0.120 mol O2 is present. Calculate Kc. I did the ICE chart and found that at equilibrium the concentrations should be: (0.245-2X). (2x). a...
- Sat Jan 09, 2021 4:46 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling week 1 #3
- Replies: 2
- Views: 108
Sapling week 1 #3
Hi! I am having trouble on this question. It's the one where Kc=53.3 and the equation is H(2)+I(2)=2HI and at a certain temp at equilibrium, 0.7 mol of I(2) and 0.7 mol of H(2) are placed in a beaker of 1.00 L and it asks for the concentration of HI at equilibrium. I did an ICE chart and found that ...
- Sat Jan 09, 2021 4:24 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Wk 1 Q2
- Replies: 3
- Views: 422
Re: Sapling Wk 1 Q2
No this doesn't really help :/ for this question, how would you get to find X without knowing the Kc. I get how to do the rest of the problem, I am just stuck on the part where at the end of the ICE chart, we are trying to find what X is and I cant seem to figure out how
- Sun Dec 13, 2020 1:14 am
- Forum: Lewis Acids & Bases
- Topic: Water
- Replies: 63
- Views: 3024
Re: Water
water is amphoteric! it can act as both an acid or a base
- Sun Dec 13, 2020 1:11 am
- Forum: Calculating the pH of Salt Solutions
- Topic: pH formula?
- Replies: 69
- Views: 4130
Re: pH formula?
pH=-log[H+]
it's also helpful to note that pH+pOH=14 and that [H+][OH-]=1*10^-14
it's also helpful to note that pH+pOH=14 and that [H+][OH-]=1*10^-14
- Sun Dec 13, 2020 1:09 am
- Forum: Identifying Acidic & Basic Salts
- Topic: Neutral Salts
- Replies: 7
- Views: 519
Re: Neutral Salts
if the anion of the salt comes from a strong base and the cation comes from a strong acid, they cancel out and have no effect on the pH and therefore they are neutral
- Sun Dec 13, 2020 1:07 am
- Forum: Identifying Acidic & Basic Salts
- Topic: rules for determining
- Replies: 7
- Views: 579
Re: rules for determining
So when I do this, I first separate the salt into its anion and its cation. From there, I try to see whether or not one of them belong to a strong acid or base and if so, they do not affect the pH of the solution. The one that does belong to the pH can affect it.
- Sun Dec 13, 2020 1:05 am
- Forum: Identifying Acidic & Basic Salts
- Topic: What is a Salt?
- Replies: 9
- Views: 715
Re: What is a Salt?
hi! A salt is an ionic compound, with both an anion and a cation. It can also become basic or acidic when in an aqueous solution depending on if the cation or anion belong to weak acids or bases
- Sun Dec 13, 2020 12:43 am
- Forum: Polyprotic Acids & Bases
- Topic: Defintion
- Replies: 39
- Views: 2595
Re: Defintion
well a polyprotic acid can break off an H+ ion more than once so when you see an acid consist of more than one H, it can indicated that
- Sun Dec 06, 2020 1:44 am
- Forum: Conjugate Acids & Bases
- Topic: Finding Conjugate A and B
- Replies: 6
- Views: 411
Re: Finding Conjugate A and B
Yes!! For conjugate acids, you would add an H+ but remove an H+ for a conjugate base
- Sun Dec 06, 2020 1:40 am
- Forum: Amphoteric Compounds
- Topic: Amphoteric
- Replies: 11
- Views: 759
Re: Amphoteric
an amphoteric substance can act as both an acid and a base and an amphiprotic substance can both accept protons and donate them. When a substance is amphiprotic it implies that it is also amphoteric.
- Sun Dec 06, 2020 1:33 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: strong vs weak
- Replies: 10
- Views: 369
Re: strong vs weak
To determine whether it is a strong acid, it would dissociate more or completely under water, in order for that to happen, the bonds in a certain molecule need to be broken more easily and therefore the bonds need to be weak. This would mean that the size of the atom in an acid would mean a lot beca...
- Sun Dec 06, 2020 1:31 am
- Forum: Lewis Acids & Bases
- Topic: Bronsted vs. Lewis bases
- Replies: 11
- Views: 430
Re: Bronsted vs. Lewis bases
Yes they are the same! We just decribe them differently! For bronsted bases, we describe them by the fact that they receive protons while for lewis bases, we describe them through them donating electrons.
- Sun Dec 06, 2020 1:27 am
- Forum: Lewis Acids & Bases
- Topic: sapling q 4
- Replies: 3
- Views: 132
Re: sapling q 4
In this case, the way I see it is that if you have NH3 which has a lone pair and wants to complete its octet and you have a H+ which can make a bond to complete its own octet, it would bind to NH3 and therefore since it doesn't have any electrons, it would be a lewis acid because it is accepting the...
- Sun Dec 06, 2020 1:23 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: pH Chart
- Replies: 16
- Views: 696
Re: pH Chart
I don't think we need to fully memorize the exact pH level of each item but it would help to have general knowledge of what items would be considered acidic or basic.
- Sun Nov 29, 2020 3:26 pm
- Forum: Hybridization
- Topic: delocalized pi bonds
- Replies: 15
- Views: 607
Re: delocalized pi bonds
delocalized pi bonds occur when there are resonance structures. If a pi bond can exist in a different region, then it is delocalized.
- Sun Nov 29, 2020 3:25 pm
- Forum: Hybridization
- Topic: Sapling #20
- Replies: 4
- Views: 234
Re: Sapling #20
regardless of what type of bond it is, it will count as one electron density. A double bond will only count as one so there are in fact only 4 electron density regions and therefore it will have an sp3 hybridization
- Sun Nov 29, 2020 3:23 pm
- Forum: Hybridization
- Topic: Hybridization for NH3
- Replies: 1
- Views: 146
Re: Hybridization for NH3
well the hybridization for NH3 would be sp3 because the nitrogen central atom has 3 bonded regions and one lone pair region (which is 4 different electron densities). When calculating the hybridization you want to first find that it is sp3 and then get more specific into finding which quantum number...
- Sun Nov 29, 2020 3:17 pm
- Forum: Hybridization
- Topic: e density
- Replies: 30
- Views: 1127
Re: e density
every bond and lone pair are seen as their own electron density yes, and on top of that a double bond would count as one electron density
- Sun Nov 29, 2020 3:16 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Week 8 sapling #18
- Replies: 3
- Views: 203
Re: Week 8 sapling #18
I think that it's because it is written as H2CCCH2 instead of just C3H4. I believe that they were implying that the hydrogens will be connected only to the outer carbons.
- Sun Nov 29, 2020 2:20 pm
- Forum: Hybridization
- Topic: sapling #11
- Replies: 11
- Views: 611
Re: sapling #11
It depends on the amount of electron regions there are attached to one atom. If there are 2 then it is an sp orbital since 1s is its own region and one p is another region. Double bonds count as one region.
- Sun Nov 22, 2020 5:03 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: lone pair position placing
- Replies: 4
- Views: 236
Re: lone pair position placing
Yes! These shapes exist because they are the ones that have the least amount of repulsion. For the square planar shapes, you want to make sure that the lone pairs are furthest away from each other and in that case, since only 4 of the 6 positions are occupied by bonded atoms, it will create a shape ...
- Sun Nov 22, 2020 4:57 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle of Molecule
- Replies: 7
- Views: 281
Re: Bond Angle of Molecule
I think that its fine to list an answer that falls in the correct margin of the answer. In this case, since we knew that there were 4 bonds, and 2 of them were lone pairs, they would cause the angle between the lone pairs to be greater than 109.5 and the angles between the lone pairs and bonding pai...
- Sun Nov 22, 2020 4:45 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pair E-
- Replies: 47
- Views: 2139
Re: Lone Pair E-
yes they count as their own separate region and have a stronger repulsion power than the rest of the regions. the powers go from lone pair to lone pair>lone pair to bonding pair>bonding pair to bonding pair. This will in turn also cause the angles between the other regions to be greater.
- Sun Nov 22, 2020 4:41 pm
- Forum: Hybridization
- Topic: Pi and Sigma Bonds
- Replies: 10
- Views: 449
Re: Pi and Sigma Bonds
I agree with the above statements, these sigma and pi bonds occur with any type of covalently bonded molecule since these molecules may consist of both double and triple bonds.
- Sun Nov 22, 2020 4:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: shape
- Replies: 6
- Views: 333
Re: shape
Well I think its best to start with drawing out the lewis structure to figure out how many bonds are present and from there when you know that there are lone pairs or not, you can figure out approximately how far the angles would be from each pair of electrons that require the least repulsion effort...
- Sun Nov 22, 2020 4:34 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma and Pi Bonds
- Replies: 24
- Views: 1267
Re: Sigma and Pi Bonds
I don't believe that a double bond are called pi bonds since it contains both a sigma bond and a pi bond. I think that the thing you need to know though about double bonds is that since it has a pi bond, it is unable to rotate.
- Sun Nov 15, 2020 10:39 pm
- Forum: Bond Lengths & Energies
- Topic: sapling #4
- Replies: 3
- Views: 194
Re: sapling #4
I agree with the above comment, when saying "ample" it is way more closer to the middle of the two bond lengths and therefore wont have significantly more than one or the other.
- Sun Nov 15, 2020 10:37 pm
- Forum: Resonance Structures
- Topic: Sapling #4
- Replies: 6
- Views: 444
Re: Sapling #4
I would keep in mind that since there is delocalization of electrons, there could be many variations as to where you can include a double bond. The whole point is to find a resonance structure that has the least amount of individual formal charges among the atoms but still keeps the same overall for...
- Sun Nov 15, 2020 10:35 pm
- Forum: Lewis Structures
- Topic: Sapling Week 5/6 HW #3
- Replies: 7
- Views: 264
Re: Sapling Week 5/6 HW #3
I doubt you would need to memorize it since we haven't learned how to formulate lewis structures or formulas based off names
- Sun Nov 15, 2020 10:23 pm
- Forum: Dipole Moments
- Topic: H-Bond acceptor
- Replies: 9
- Views: 456
Re: H-Bond acceptor
No, the hydrogen needs to be attached to either F,N,O but the other atom just has to be electronegative.
- Sun Nov 15, 2020 10:18 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Sapling #9 week 5/6
- Replies: 13
- Views: 767
Re: Sapling #9 week 5/6
In order to find the formal charge, you look at each atom within the molecule and find its formal charge. The resonance structure with the lowest amount of charges and changes will be the best one
- Sun Nov 15, 2020 10:17 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation Number
- Replies: 8
- Views: 439
Re: Oxidation Number
It's just something you would need to know conceptually. Like for carbon, it would be a +4 because all the electrons move away from it to the more electronegative atom
- Sun Nov 08, 2020 3:46 pm
- Forum: Lewis Structures
- Topic: Negative Sign
- Replies: 12
- Views: 890
Re: Negative Sign
The negative sign will be on the outside of the molecule and it is used to dictate the charge of the molecule based on how many electrons it will need to complete an octet and to be stable
- Sun Nov 08, 2020 3:44 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Equation
- Replies: 16
- Views: 641
Re: Formal Charge Equation
L represents the number of lone pairs and they can be counted in the lewis dot diagram
- Sun Nov 08, 2020 3:39 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Sapling #2 weeks 5
- Replies: 3
- Views: 118
Re: Sapling #2 weeks 5
The way to draw this: you first start by making a single pair of each oxygen to the carbon. You notice that carbon still has a free electron that could bond with one of the oxygens to fill its octet, so it forms a double bond with one of the oxygen atoms which fills up the octet for that atom as wel...
- Sun Nov 08, 2020 3:34 pm
- Forum: Resonance Structures
- Topic: Resonance & Stability
- Replies: 4
- Views: 237
Re: Resonance & Stability
to have several resonance structures allows for the electron density to be more evenly distributed and therefore the overall charge of the components in the molecule will be more neutral and therefore more stable.
- Sun Nov 08, 2020 3:24 pm
- Forum: Electronegativity
- Topic: Electronegativity Table/Chart in Lecture
- Replies: 14
- Views: 546
Re: Electronegativity Table/Chart in Lecture
Hi! So I don't think we will have to know the exact value of the electronegativity of each element but we will need to know the general trends of electronegativity that occur in the periodic table and where electronegative atoms are found more.
- Sun Nov 08, 2020 3:21 pm
- Forum: Lewis Structures
- Topic: Lewis Structure for BrF3
- Replies: 6
- Views: 567
Re: Lewis Structure for BrF3
I agree with everyone above, it must fill its octet and have 6 valence electrons. The book probably forgot to input the 2 electrons
- Sat Oct 31, 2020 3:35 pm
- Forum: Ionic & Covalent Bonds
- Topic: lone pairs
- Replies: 5
- Views: 373
Re: lone pairs
yes! They usually are easier to lose or cause the atom to want to gain an electron to finish the orbital
- Sat Oct 31, 2020 3:32 pm
- Forum: Ionic & Covalent Bonds
- Topic: Is ionic or covalent stronger?
- Replies: 31
- Views: 16780
Re: Is ionic or covalent stronger?
ionic bonds are usually stronger because they are causing a transfer in electrons rather than a quick sharing of them. Covalent bonds are created by electronegativity and tend to be weaker
- Sat Oct 31, 2020 3:29 pm
- Forum: Electronegativity
- Topic: Electronegativity
- Replies: 10
- Views: 655
Re: Electronegativity
typically electronegative atoms make covalent bonds and are non metal. It is more electronegative when it wants more electrons. For example, in H2O, Oxygen is very electronegative and that is why it bonds with 2 hydrogen atoms.
- Sat Oct 31, 2020 3:27 pm
- Forum: Lewis Structures
- Topic: Lewis Structures
- Replies: 7
- Views: 567
Re: Lewis Structures
Use the atom with the lowest ionization energy (this is the least electromagnetic atom)
- Sat Oct 31, 2020 3:24 pm
- Forum: Ionic & Covalent Bonds
- Topic: Inert vs Noble Gas
- Replies: 4
- Views: 240
Re: Inert vs Noble Gas
Hey! So im pretty sure both terms can be used interchangeably since noble gases are in the outermost level of the periodic table and don't partake in chemical reactions and inert gases are defined as not partaking in chemical reactions.
- Sat Oct 31, 2020 3:16 pm
- Forum: Octet Exceptions
- Topic: Octet exception
- Replies: 14
- Views: 1295
Re: Octet exception
H, He, Li, Be are not part of the octet rule because H and He only need to fill up an S orbital to satisfy the orbital and since Li and Be are closest to Helium, they will lost electrons to reach the amount of valence electrons/the state of helium and therefore they don't and won't have to fill an 8...
- Fri Oct 23, 2020 2:18 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Light's effects
- Replies: 8
- Views: 281
Re: Light's effects
Hi! So I think that the electron is affected by the photon due to its size and mass. It was said during the lecture that a baseball wouldn't be affected because it is so big and therefore wouldn't feel the affects of the photon
- Fri Oct 23, 2020 2:13 am
- Forum: Properties of Electrons
- Topic: Sapling 2 HW #6
- Replies: 10
- Views: 561
Re: Sapling 2 HW #6
Hi! So since it is excited to the n=6 level, it can return to any level below it (n=5,4,3,2,1) so it will have 5 different spectral lines.
To find the wavelength, we can use the rydberg formula to find the frequency and then, in turn you can use c=(wavelength)(frequency) to get the wavelength.
To find the wavelength, we can use the rydberg formula to find the frequency and then, in turn you can use c=(wavelength)(frequency) to get the wavelength.
- Fri Oct 23, 2020 12:04 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Energy Levels
- Replies: 8
- Views: 388
Re: Energy Levels
Hi! So I think what he meant in his lecture was that the energy of the photon has to be atleast equal to/match the energy needed to move the electron up an energy level. It just can't be less than the needed energy to eject it.