Search found 137 matches
- Tue Mar 10, 2020 10:45 pm
- Forum: General Rate Laws
- Topic: Equations
- Replies: 5
- Views: 412
Re: Equations
It is provided on your equation sheet but it is useful to know how to derive the half life ones since let's say you are asked to find the how much time it takes for the concentration to be 1/15 initial, you would first need to derive an equation for that (exactly the way you do for half life) then s...
- Tue Mar 10, 2020 10:43 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: How to calculate for n
- Replies: 7
- Views: 581
Re: How to calculate for n
n is the number of electron that are being transferred
- Tue Mar 10, 2020 10:42 pm
- Forum: General Rate Laws
- Topic: pseudo rate laws
- Replies: 5
- Views: 310
Re: pseudo rate laws
To differentiate with the actual rate constant
- Tue Mar 10, 2020 10:41 pm
- Forum: Ideal Gases
- Topic: Acids and Basis: Salts
- Replies: 9
- Views: 613
Re: Acids and Basis: Salts
That's the ICE table problem!
- Tue Mar 10, 2020 10:41 pm
- Forum: General Rate Laws
- Topic: Difference between initial reaction rate vs reaction rate
- Replies: 1
- Views: 207
Re: Difference between initial reaction rate vs reaction rate
Initial rate is the rate that you use when trying to figure out what is the rate constant,k. It is when the reaction first starts so no products has formed. Reaction rate is your rate law: rate = k[P]. This is the rate of your rxn as a whole when it reaches equilibrium
- Sat Mar 07, 2020 6:23 pm
- Forum: Second Order Reactions
- Topic: 7B.13
- Replies: 5
- Views: 458
7B.13
For this question: The half-life for the second-order reaction of a substance A is 50.5 s when [A]0 0.84M . Calculate the time needed for the concentration of A to decrease to (a) one sixteenth; (b) one-fourth; (c) one-fi fth of its original value. So for this question, I calculate k (0.0236) and th...
- Tue Mar 03, 2020 12:59 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Rate Constant, k
- Replies: 4
- Views: 356
Re: Rate Constant, k
Unit of k is depend on your order
- Tue Mar 03, 2020 12:56 pm
- Forum: Second Order Reactions
- Topic: [A] v. Time
- Replies: 27
- Views: 1151
Re: [A] v. Time
Linear
- Tue Mar 03, 2020 12:55 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Platinum
- Replies: 6
- Views: 384
Re: Platinum
You use Plt (s) when you don’t have an inert conducting metal solid
- Tue Mar 03, 2020 12:55 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: n
- Replies: 4
- Views: 355
Re: n
You would determine it from your half reaction (making sure that both of them have the same number of electrons; if not, multiply one with another)
- Tue Mar 03, 2020 12:53 pm
- Forum: Balancing Redox Reactions
- Topic: Acidic/Basic Solution
- Replies: 2
- Views: 221
Re: Acidic/Basic Solution
As of the resulting balanced REDOX, no it does not matter where the H+ or OH- ends up on. Just remember if acidic, your rxn should have H+ and basic, OH-
- Sat Feb 29, 2020 1:59 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Le Chateliers with Ecell
- Replies: 2
- Views: 240
Re: Le Chateliers with Ecell
It applies like how you would in equilibrium
- Sat Feb 29, 2020 1:58 pm
- Forum: Balancing Redox Reactions
- Topic: Reducing/Oxidizing Agents
- Replies: 13
- Views: 604
Re: Reducing/Oxidizing Agents
It's vice versa with the ones being oxidized/ reduced. The oxidized one is the reducing agent (think about it, if let's say H is being oxidized, it can go around oxidizing anyone else, thus, someone has to oxidize it, thus it is a reducing agent)
- Sat Feb 29, 2020 1:56 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Spontaneous reactions
- Replies: 6
- Views: 425
Re: Spontaneous reactions
It doesn't affect but a positive cell potential means a negative Gibbs free energy which mean spontaneous
- Sat Feb 29, 2020 1:54 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: E potentials
- Replies: 5
- Views: 424
Re: E potentials
It will always be given for reduction
- Sat Feb 29, 2020 1:53 pm
- Forum: Balancing Redox Reactions
- Topic: Cell Diagrams
- Replies: 14
- Views: 937
Re: Cell Diagrams
For cell diagram, anode always on the left, then salt bridge (||) then cathode
- Sun Feb 23, 2020 11:45 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Writing cell diagram
- Replies: 2
- Views: 201
Re: Writing cell diagram
JonathanS 1H wrote:The answer to both questions is that Hg (l) is the anode in this case. With a liquid anode, we include the liquid but since water is our solvent and not involved in either the anode or cathode, we do not include it in the cell diagram.
So if the anode is in liquid state, we don’t need any metal?
- Sun Feb 23, 2020 4:09 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Identify the state
- Replies: 3
- Views: 237
Identify the state
Suppose that each of the following pairs of redox couples is joined to form a galvanic cell that generates a current under standard conditions. Identify the oxidizing agent and the reducing agent, write a cell diagram, and calculate the standard cell potential. a) Co 2+/Co and Ti 3+/Ti 2+ So for thi...
- Sun Feb 23, 2020 2:33 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Writing cell diagram
- Replies: 2
- Views: 201
Writing cell diagram
So I have several questions regarding writing cell diagram (I'm also refering to 6M.5: For each reaction that is spontaneous under standard conditions (that is, K > 1), write a cell diagram, determine the standard cell potential, and calculate ΔG° for the reaction: (a) 2 NO3 − (aq) + 8 H + (aq) + 6 ...
- Sun Feb 23, 2020 12:38 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6M.1
- Replies: 2
- Views: 149
Re: 6M.1
You have the numbers correct. but should double-check the arrangement of the final equation you are using to solve. Should be like this... Ecell = E cathode - E anode (solving for E cathode...) E cathode = E cell + E anode E cathode = -.698V + .34V = -.349V Wait im confused, why are we solving for ...
- Sat Feb 22, 2020 11:40 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6M.1
- Replies: 2
- Views: 149
6M.1
A student was given a standard Cu(s)|Cu2+ (aq) half-cell containing an unknown metal M in 1.00 m M(NO3)2(aq) and formed the cell M(s)|M+ (aq) || Cu 2+ (aq)|Cu(s). The cell potential was found to be -0.689 V. What is the value of E°(M 2+|M)? So for this problem, I identify the anode (M(s)-> M+ + e)...
- Sat Feb 22, 2020 10:02 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Writing half-rxn
- Replies: 3
- Views: 251
Re: Writing half-rxn
I think we might be provided with half reactions but also it would be good to practice coming up with them on our own? If we are not given, then do you know any strategy to do so? Because for this rxn specifically, there is no way I could have come up with Ag(s) -> Ag+ + e and AgBr + e -> Ag + Br
- Sat Feb 22, 2020 9:42 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Writing half-rxn
- Replies: 3
- Views: 251
Writing half-rxn
6L.7: Write the half-reactions and devise a galvanic cell (write a cell diagram) to study each of the following reactions:
a) AgBr(s)-->Ag+(aq)+Br-(aq)
For this type of question, are we refering to all the half rxn in Appendix 2A or a we expected to come up with them on our own??
a) AgBr(s)-->Ag+(aq)+Br-(aq)
For this type of question, are we refering to all the half rxn in Appendix 2A or a we expected to come up with them on our own??
- Thu Feb 20, 2020 9:57 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Adiabatic systems
- Replies: 14
- Views: 776
Re: Adiabatic systems
Yes, always
- Thu Feb 20, 2020 9:56 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Purpose of Salt Bridge
- Replies: 12
- Views: 769
Re: Purpose of Salt Bridge
To keep the electrons flowing back so that the "negative" doesn't build up on the cathode side
- Thu Feb 20, 2020 9:55 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Half cells
- Replies: 2
- Views: 185
Re: Half cells
No they refer to anything. Hydrogen is just the standard use to measure E knot
- Thu Feb 20, 2020 9:54 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: converting T to kelvin
- Replies: 46
- Views: 3292
Re: converting T to kelvin
Depends on the equation you are using but I think if in doubt, just convert it to K (unless they are problems that involve a specific heat capacity ones)
- Thu Feb 20, 2020 9:52 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cells
- Replies: 8
- Views: 440
Re: Galvanic Cells
Basically to produce electricity (eg. battery)
- Sat Feb 15, 2020 7:12 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Unit for Pressure in delta G equation
- Replies: 2
- Views: 212
Unit for Pressure in delta G equation
For this equation: deltaG = deltaG knot + RTlnQ. If we are given the pressure to find Q, what would be the unit for the pressure? I am refering to 5G.13
- Wed Feb 12, 2020 2:57 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 4F. 11
- Replies: 3
- Views: 245
Re: 4F. 11
Use the ideal gas law. Usually when you are not given anything,there is a high chance you are able to get it by the ideal gas law
- Wed Feb 12, 2020 2:47 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: P1/P2
- Replies: 10
- Views: 1161
Re: P1/P2
Because P and V has an inverse relationship. If you increases one, one wil decreases (PV=nRT)
- Wed Feb 12, 2020 2:46 pm
- Forum: Calculating Work of Expansion
- Topic: work in reversible reaction
- Replies: 4
- Views: 272
Re: work in reversible reaction
d is delta. In Calculus, it is the derivative. In this case, it is the change in volume.
- Wed Feb 12, 2020 2:44 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: q of ice and q of water
- Replies: 8
- Views: 1495
Re: q of ice and q of water
Because all the heat lost by water ( - sign) has to be gained by ice ( + sign). Even though it doesn't matter, it is conventional to put the negative sign on the side that lost heat, and since heat flows from hot to cold, in this case, you would put the negative sign on q water
- Wed Feb 12, 2020 2:42 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Cubic to quadratic function
- Replies: 4
- Views: 412
Re: Cubic to quadratic function
We are not having any cubic equation on the test. If there is, you would use an approximation.
- Sat Feb 08, 2020 5:17 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 4J.5
- Replies: 2
- Views: 457
4J.5
Write a balanced chemical equation for the formation reaction of (a) NH3 (g ); (b) H2O (g ); (c) CO; (d) NO2 (g) . For each reaction, determine Δ G ° from data in Appendix 2A. For this problem, my understanding is that we just need to find the Δ G ° from the table right? However, all the answers are...
- Sat Feb 08, 2020 4:27 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 4J.3 part b
- Replies: 1
- Views: 84
4J.3 part b
Calculate the change in molar Gibbs free energy for the process NH3(l) S NH3(g) at 1 atm (b) -180 deg C. In each case, indicate whether vaporization would be spontaneous. So for this one, I did exactly what I did for part a which is dG = dH - TdS. dH is 23400 J/mol dS is 97.6 J/K.mol T is -180 + 273...
- Sat Feb 08, 2020 1:34 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Equation for Cv and Cp
- Replies: 3
- Views: 174
Re: Equation for Cv and Cp
Janet Nguy 2C wrote:For diatomic molecules, Cv = 5/2R and Cp = 7/2R. I'm not sure about the other kind, though. But I don't think we would be asked something that's not monatomic or diatomic.
So, we just have to remember for diatomic then?
- Sat Feb 08, 2020 1:33 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: 4H.11 d
- Replies: 1
- Views: 151
4H.11 d
Use data in Table 4H.1 or Appendix 2A to calculate the standard reaction entropy for each of the following reactions at 25°C. For each reaction, interpret the sign and magnitude of the reaction entropy. (d) The decomposition of potassium chlorate: 4KClO4 -> 3KClO4 + KCl So for this problem, why don'...
- Sat Feb 08, 2020 12:59 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Equation for Cv and Cp
- Replies: 3
- Views: 174
Equation for Cv and Cp
I know the equations for Cv and Cp for monoatomic gases are given on the equation sheet but what about for diatomic and nonlinear? Are we expected to know them for the midterm?
- Tue Feb 04, 2020 9:36 am
- 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: Degeneracy
- Replies: 1
- Views: 67
Degeneracy
Can someone explain this concept to me please? Like why and when are we using it? I know it has something to do with the probabilities of how the atoms can arrange but other than that, I don't get all the calculation and its meaning
- Tue Feb 04, 2020 9:32 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: reaction enthalpy
- Replies: 14
- Views: 451
Re: reaction enthalpy
Elizabeth Harty 1A wrote:In the thermodynamics outline what does the bullet point "calculate enthalpy changes from calorimetric data" mean?
I think he is referring to deltaH rxn so like the 3 ways and the q=mcdeltaT
- Tue Feb 04, 2020 9:29 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: R vs C
- Replies: 2
- Views: 104
Re: R vs C
Both of them would have to be given to you if they are needed in a problem. R is the gas constant and there are different constants depending on their unit. c is the (specific or molar) heat capacity, which is different for each substances or element etc.
- Tue Feb 04, 2020 9:27 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy
- Replies: 2
- Views: 106
Re: Enthalpy
Enthalpy is the heat transferred. So change in enthalpy, delta H, is the change in heat during a rxn. A negative value means the rxn gives off heat, hence exothermic. Simillarly, a positive value means the rxn requires heat, hence endothermic.
- Tue Feb 04, 2020 9:24 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Extensive Property
- Replies: 4
- Views: 275
Re: Extensive Property
Extensive property is anything that can change, mainly based on your mass. Such as weight, the more you have of something, the "more" weight you have. Other examples would be volume or length
- Sun Feb 02, 2020 11:32 pm
- Forum: Calculating Work of Expansion
- Topic: 4.7 answer
- Replies: 1
- Views: 87
4.7 answer
a) Calculate the work that must be done against the atmosphere for the expansion of the gaseous products in the combustion of 1.00 mol C6H6 (l) at 25C and 1.00 bar. So for this question, I first use PV=nRT (R= 8.314 x 10^-2) to get V. I got V = 24.8L. Then convert P into atm (1 bar = 0.987 atm) and ...
- Sat Feb 01, 2020 5:31 pm
- Forum: Calculating Work of Expansion
- Topic: Gas constant
- Replies: 5
- Views: 254
Gas constant
A piston confines 0.200mol Ne(g) in 1.20L at 25C. part (a)The gas is allowed to expand through an additional 1.20L against a constant pressure of 1.00 atm. b) The gas is allowed to expand reversibly and isothermally to the same final volume. So I want to calculate the work done for part b but I don'...
- Tue Jan 28, 2020 11:45 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpies
- Replies: 4
- Views: 214
Re: Enthalpies
Standard enthalpies of formation is when all the R are in their most stable state, forming P
- Tue Jan 28, 2020 11:42 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Best Method of the 3 Given?
- Replies: 7
- Views: 219
Re: Best Method of the 3 Given?
If you are asking for when to use what, it is obviously going to depend on the information you are given. However, as of like theoretical accuracy, bond enthalpies method is the least accurate because the value that are given to you are the average bond enthalpies, not exact. So it would be off comp...
- Tue Jan 28, 2020 11:39 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: System vs Surroundings
- Replies: 14
- Views: 2050
Re: System vs Surroundings
System is the one that you are focusing on. In most cases, it is the chemical rxn
- Tue Jan 28, 2020 11:38 pm
- Forum: Phase Changes & Related Calculations
- Topic: steam at 100ºC burn worse
- Replies: 7
- Views: 883
Re: steam at 100ºC burn worse
Because the energy it takes for liquid to become steam require more energy. So when the steam touch your skin, the steam has to condensate, meaning turns back into liquid phase and when it does that, it releases all the energy
- Tue Jan 28, 2020 11:36 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase change and temp
- Replies: 8
- Views: 279
Re: Phase change and temp
Because all the energy are being used to either break a bond or form a bond, thus no energy is used for heating up the material
- Tue Jan 28, 2020 11:35 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Heat Supplied to a system
- Replies: 6
- Views: 434
Re: Heat Supplied to a system
You need the mass to use q=mc(delta)T
- Tue Jan 28, 2020 11:34 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Order of homework for Thermochem unit
- Replies: 6
- Views: 311
Re: Order of homework for Thermochem unit
I think right now it is 4C and 4E
- Mon Jan 27, 2020 12:57 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard enthalpies of formation
- Replies: 7
- Views: 585
Re: Standard enthalpies of formation
I highly doubt that we'll be required to memorize enthalpies of formation, so I assume they'll be given on a test. This would be a good question for Dr. Lavelle himself. Remember which ones can be cancelled because they're in their base state, though. You might have to memorize those, but I believe...
- Sun Jan 26, 2020 10:30 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard enthalpies of formation
- Replies: 7
- Views: 585
Standard enthalpies of formation
Hi, for questions such as 4D.9, are we supposed to Google the delta H for each compound?? I can't seem to find any table or something like that in the book? Is that the case for all the other problems that want us to find deltaH too?
- Wed Jan 22, 2020 12:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Determining pH
- Replies: 3
- Views: 88
Re: Determining pH
Weak acids and bases are just those not considered strong. I think you just need to memorize them. The strong acids include most halogens and some oxoacids like HCl, HI, HBr, HClO4, HNO3, and H2SO4. The strong bases include Group 1 and heavy group 2 hydroxides, like LiOH and B(OH)2. Thank you for y...
- Wed Jan 22, 2020 10:44 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Determining pH
- Replies: 3
- Views: 88
Determining pH
Rank the following solutions in order of increasing pH: A) .00005 M HCl B) .2 M CH3NH3Cl C) .2 M CH3COOH D) .2 M C6H5NH2 justify your ranking. So for this one, I believe we are using the ICE box for the weak ones but (might be a silly question) but how would I know if those solutions are weak bases ...
- Tue Jan 21, 2020 10:21 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Sig Figs for pH/pOH
- Replies: 7
- Views: 332
Re: Sig Figs for pH/pOH
Basically the digit before the “.” doesn’t count as sig fig. For example, pH =3.98 only has 2 sig fig. You count after the decimal place. However, the concentration of OH or H3O follow the usual rule.
- Tue Jan 21, 2020 10:19 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: X was ignored
- Replies: 27
- Views: 1003
Re: X was ignored
Because your Ka is less than 10^-3. Since Ka then is so small, you can ignore it for the denominator
- Tue Jan 21, 2020 10:18 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle
- Replies: 19
- Views: 1615
Re: Le Chatelier's Principle
When something is disturbing your chemical equilibrium and you want to see what happen next
- Tue Jan 21, 2020 10:17 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction Q
- Replies: 7
- Views: 368
Re: Reaction Q
Reaction Quotient, Q, tells us the direction the rxn will shift in order to achieve equilibrium
- Tue Jan 21, 2020 10:16 am
- Forum: Ideal Gases
- Topic: Kc vs Kp
- Replies: 109
- Views: 4390
Re: Kc vs Kp
If all the reactants are gas then use Kp. You can calculate Kc for gas too but they would have to explicitly tell you so
- Sat Jan 18, 2020 1:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 6E.1
- Replies: 1
- Views: 173
6E.1
So the question ask for the pH of 0.15M H2SO4. Since it is a strong acid, I just take the negative log of it and gets 0.82 as the answer. However, the back of the book's answer is 0.80. Did I do something wrong?
- Fri Jan 17, 2020 12:16 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 6B.9
- Replies: 3
- Views: 225
Re: 6B.9
I didnt get the same ans as the back of the textbook either! For i i got -0.176 for pH instead of 0.176. There's probably a typo somewhere (??!), I hope
- Tue Jan 14, 2020 2:39 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: What is this?
- Replies: 23
- Views: 1393
Re: What is this?
It basically says that the rxn likes to be in its equilibrium state and it will always try to be(adjust) in its equilibrium state. Therefore, when you change the rxn in someway such as adding a reactant or increasing the volume, etc. the rxn would shift to the corresponding side to adjust back to it...
- Tue Jan 14, 2020 2:37 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change on Same Side
- Replies: 6
- Views: 201
Re: Change on Same Side
If we add N2, then NH3 would increase since the rxn wants to maintain its equilibrium state. In order to make NH3, you need both N2 and H2 so your H2 concentration would decrease as the result.
- Tue Jan 14, 2020 2:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Strong Acids/Bases
- Replies: 4
- Views: 146
Re: Strong Acids/Bases
Strong acids or strong bases disassociate completely in rxn. Therefore if you want theirs concentration, you only need the concentration of the acid/base since they are also the concentration of your H+ and OH-. However, weak acids/base do not disassociate completely. That’s when your ICE table come...
- Tue Jan 14, 2020 2:33 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Which liquids to use
- Replies: 7
- Views: 171
Re: Which liquids to use
Only use aqueous and gas for K. You probably misunderstood aqueous for liquid.
- Tue Jan 14, 2020 2:32 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Expansion
- Replies: 5
- Views: 153
Re: Expansion
It would make the rxn shifts to one way or another but K is remains unchanged
- Tue Jan 07, 2020 11:56 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Q vs K
- Replies: 13
- Views: 450
Re: Q vs K
K is the value of molarity of P/R at equilibrium while Q is not at equilibrium (usually at initial condition). They are, however, calculated the same. Molarity or partial pressure ratio of P/R
- Tue Jan 07, 2020 11:55 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Textbook example 5H.1
- Replies: 2
- Views: 132
Re: Textbook example 5H.1
R is a gas constant so it is given. There are multiple R correspond to the different units so choose the one that fits your data the most! And all of the ones we need are on the equation sheet
- Tue Jan 07, 2020 3:01 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constant for Solids/Gases
- Replies: 5
- Views: 193
Re: Equilibrium Constant for Solids/Gases
Taking them out doesn’t mean there’s nothing there. Since K is Product over Reactant, you have to indicate that there is Product, so you put 1 there. If you just put [A][B], it would mean that those are the concentration of your products
- Tue Jan 07, 2020 2:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Very Large K
- Replies: 12
- Views: 2534
Re: Very Large K
Since K is just Product/ Reaction. A large K means a large amount of Product, so the rxn would mainly producing product or shifting to the right
- Tue Jan 07, 2020 2:56 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Writing expression for K
- Replies: 5
- Views: 196
Re: Writing expression for K
If everything is gas then you use P but otherwise, use concentration […]
- Thu Dec 05, 2019 3:05 am
- Forum: Bronsted Acids & Bases
- Topic: Relative strength of base?
- Replies: 3
- Views: 229
Re: Relative strength of base?
Yes you would look at the same characteristics to determine the strength of a base. Essentially a stronger base, wants to accept a proton easier, and will give off more hydroxide ion. So how would that work though? Cause like for acid, you look at the strength between H and A (the bigger the A, the...
- Wed Dec 04, 2019 10:53 pm
- Forum: Bronsted Acids & Bases
- Topic: Relative strength of base?
- Replies: 3
- Views: 229
Relative strength of base?
How do you determine the relative strengths of 2 bases to see which one is stronger? I know for acids, you look at bond length and the anion’s stability so does the same logic apply to bases too?
- Wed Dec 04, 2019 10:50 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acid Strength
- Replies: 5
- Views: 360
Re: Acid Strength
You would look at bond length first. If it’s the same then you look at the resulting anion’s stability (electronegativity, resonance...)
- Wed Dec 04, 2019 10:49 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: 1E.5 part d
- Replies: 1
- Views: 172
1E.5 part d
For 1E.5 part d, the problem asks to tell whether a statement is true or false. d) Zeff e for an electron in a p-orbital is lower than for an electron in an s-orbital in the same shell I approach this question by thinking that since both are on the same shell, their distance from the nucleus are the...
- Tue Dec 03, 2019 1:14 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: 6C.21
- Replies: 2
- Views: 220
6C.21
For question such as 6C.21, are we expected to know the formula trichloroacetic acid or formic acid?
I know he says that naming things is not on the test but in class, he did go over it so is it fair game?
I know he says that naming things is not on the test but in class, he did go over it so is it fair game?
- Mon Dec 02, 2019 11:36 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Anion stability
- Replies: 6
- Views: 453
Re: Anion stability
Usually the more resonance it has the more stable it is since electrons are "floating" around.
- Mon Dec 02, 2019 11:34 pm
- Forum: Conjugate Acids & Bases
- Topic: how to figure out?
- Replies: 12
- Views: 678
Re: how to figure out?
Whatever your acid is in the reactant side, it would become your conj. base in the product side. Let's say your acid is HBr, after it gives of the H+, Br- is your conjugate base
And of course, vice versa with base and conj. acid
And of course, vice versa with base and conj. acid
- Mon Dec 02, 2019 11:30 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Formal Charge and its effect on Shape
- Replies: 3
- Views: 229
Re: Formal Charge and its effect on Shape
You are trying to make all the formal charges of each element equal to 0. Of course, if the compound as a whole has a negative or positive charge, at least one of them have to have a charged. When that happens, put the negative charge on the more electronegative one.
- Mon Dec 02, 2019 11:28 pm
- Forum: Bronsted Acids & Bases
- Topic: strong v weak acids
- Replies: 8
- Views: 441
Re: strong v weak acids
It would be a smart move to do so!
- Mon Dec 02, 2019 11:24 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Electronegativity and acid strength
- Replies: 5
- Views: 251
Re: Electronegativity and acid strength
Since in both HBrO and HClO has the same OH bond, you have to look at the anion after the H+ has been removed. Then, the one with the element that is more electronegative is the stronger acid. Why? Because higher electronegativity means that element would pull on the electron from the partially nega...
- Thu Nov 28, 2019 11:20 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acid Strength
- Replies: 6
- Views: 400
Re: Acid Strength
I think memorization is the best way
- Thu Nov 28, 2019 11:19 pm
- Forum: Bronsted Acids & Bases
- Topic: 6A9
- Replies: 2
- Views: 209
Re: 6A9
The way I do it is to look which compound in the products side have gained or lost a H+. If it has gained then the similar reactant must have been a base and vice versa
- Thu Nov 28, 2019 11:17 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Lewis Acid/Base
- Replies: 5
- Views: 217
Re: Lewis Acid/Base
Lewis acid is a compound that accepts electrons while lewis base donates electron
- Thu Nov 28, 2019 11:15 pm
- Forum: Hybridization
- Topic: Sigma and Pi bonds
- Replies: 7
- Views: 480
Re: Sigma and Pi bonds
Single bond: 1 sigma
Double: 1 sigma and 1 pi
Triple: 1 sigma and 2 pi
Double: 1 sigma and 1 pi
Triple: 1 sigma and 2 pi
- Thu Nov 28, 2019 11:14 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Bronsted Acid/Base
- Replies: 4
- Views: 255
Re: Bronsted Acid/Base
Bronsted acid is a compound that donates H+ in solution while Bronsted base is a compound that accepts the H+
9C.3
For question 9C.3, the problem tells us to use the table to write the formula for the coordination com#. My question is on the final exam, if we have one of these questions, are we gonna be given the table or do we have to memorize it?
- Fri Nov 22, 2019 4:30 pm
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate covalent bonds
- Replies: 9
- Views: 739
Re: Coordinate covalent bonds
Angela Prince 3B wrote:Do coordinate covalent bonds happen only in transition metals?
And does it occur in all transition metals or are there exceptions?
I think just in transition metal
- Fri Nov 22, 2019 4:29 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Acids
- Replies: 6
- Views: 442
Re: Acids
Whether it dissociate completely in water or not. Strong acid theoretically would dissociate 100% in water
- Fri Nov 22, 2019 4:28 pm
- Forum: Lewis Structures
- Topic: Cis- vs Trans- bonds
- Replies: 5
- Views: 437
Re: Cis- vs Trans- bonds
It’s fair game since he did talk about it in class. Cis means the dipole moment cant cancel each other out while trans they do
- Fri Nov 22, 2019 4:26 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: bent v. angular
- Replies: 27
- Views: 1429
Re: bent v. angular
They are the same shape
- Fri Nov 22, 2019 4:26 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: LDF vs dipole-dipole
- Replies: 4
- Views: 360
Re: LDF vs dipole-dipole
Yes since different atoms have different strengths or forces
- Fri Nov 22, 2019 4:25 pm
- Forum: Hybridization
- Topic: hybridizing d orbitals
- Replies: 7
- Views: 417
- Fri Nov 15, 2019 6:06 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E.29 B
- Replies: 1
- Views: 95
Re: 2E.29 B
Yes, you are correct when saying that the dipole is based on the distance so that's why structure I is greater. Since the 2 Cl- with the same (-) charge repel each other more when they are closer together, creating a stronger dipole moment. If the 2 Cl- are far from each other (II), then the repulsi...
- Fri Nov 15, 2019 5:54 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E.25 part a
- Replies: 1
- Views: 107
2E.25 part a
Draw the Lewis structure and predict whether each of the following molecules is polar or non-polar? a) CH2Cl2 For this one, correct me if I am wrong please but when I draw the Lewis structure out, C is the central atom. From here, I can either place the 2 Cl opposite each other on the axial position...
- Fri Nov 15, 2019 5:37 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E.21 a & d
- Replies: 2
- Views: 118
Re: 2E.21 a & d
Could someone explain the shape and bond angles of C2H4? I don't understand why it's trigonal planar. Also, I don't understand the answer for the shape and bond angles of N2H4. If someone could explain that as well that would be great! As of shape and bond angles of N2H4, the lewis structure for it...
- Fri Nov 15, 2019 5:35 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E.21 a & d
- Replies: 2
- Views: 118
Re: 2E.21 a & d
C2H4 is trigonal planar around the C atom because it bonds to 2 H and double bond to another C, therefore it has 3 e- density around it => trigonal planar.