Search found 137 matches

by Minh Ngo 4G
Tue Mar 10, 2020 10:45 pm
Forum: General Rate Laws
Topic: Equations
Replies: 5
Views: 59

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...
by Minh Ngo 4G
Tue Mar 10, 2020 10:43 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: How to calculate for n
Replies: 7
Views: 104

Re: How to calculate for n

n is the number of electron that are being transferred
by Minh Ngo 4G
Tue Mar 10, 2020 10:42 pm
Forum: General Rate Laws
Topic: pseudo rate laws
Replies: 5
Views: 52

Re: pseudo rate laws

To differentiate with the actual rate constant
by Minh Ngo 4G
Tue Mar 10, 2020 10:41 pm
Forum: Ideal Gases
Topic: Acids and Basis: Salts
Replies: 9
Views: 120

Re: Acids and Basis: Salts

That's the ICE table problem!
by Minh Ngo 4G
Tue Mar 10, 2020 10:41 pm
Forum: General Rate Laws
Topic: Difference between initial reaction rate vs reaction rate
Replies: 1
Views: 29

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
by Minh Ngo 4G
Sat Mar 07, 2020 6:23 pm
Forum: Second Order Reactions
Topic: 7B.13
Replies: 5
Views: 116

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...
by Minh Ngo 4G
Tue Mar 03, 2020 12:59 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Rate Constant, k
Replies: 4
Views: 62

Re: Rate Constant, k

Unit of k is depend on your order
by Minh Ngo 4G
Tue Mar 03, 2020 12:56 pm
Forum: Second Order Reactions
Topic: [A] v. Time
Replies: 16
Views: 174

Re: [A] v. Time

Linear
by Minh Ngo 4G
Tue Mar 03, 2020 12:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Platinum
Replies: 6
Views: 42

Re: Platinum

You use Plt (s) when you don’t have an inert conducting metal solid
by Minh Ngo 4G
Tue Mar 03, 2020 12:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: n
Replies: 4
Views: 41

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)
by Minh Ngo 4G
Tue Mar 03, 2020 12:53 pm
Forum: Balancing Redox Reactions
Topic: Acidic/Basic Solution
Replies: 2
Views: 30

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-
by Minh Ngo 4G
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: 29

Re: Le Chateliers with Ecell

It applies like how you would in equilibrium
by Minh Ngo 4G
Sat Feb 29, 2020 1:58 pm
Forum: Balancing Redox Reactions
Topic: Reducing/Oxidizing Agents
Replies: 13
Views: 76

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)
by Minh Ngo 4G
Sat Feb 29, 2020 1:56 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Spontaneous reactions
Replies: 6
Views: 45

Re: Spontaneous reactions

It doesn't affect but a positive cell potential means a negative Gibbs free energy which mean spontaneous
by Minh Ngo 4G
Sat Feb 29, 2020 1:54 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: E potentials
Replies: 5
Views: 59

Re: E potentials

It will always be given for reduction
by Minh Ngo 4G
Sat Feb 29, 2020 1:53 pm
Forum: Balancing Redox Reactions
Topic: Cell Diagrams
Replies: 14
Views: 123

Re: Cell Diagrams

For cell diagram, anode always on the left, then salt bridge (||) then cathode
by Minh Ngo 4G
Sun Feb 23, 2020 11:45 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing cell diagram
Replies: 2
Views: 53

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?
by Minh Ngo 4G
Sun Feb 23, 2020 4:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Identify the state
Replies: 3
Views: 31

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...
by Minh Ngo 4G
Sun Feb 23, 2020 2:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing cell diagram
Replies: 2
Views: 53

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 ...
by Minh Ngo 4G
Sun Feb 23, 2020 12:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M.1
Replies: 2
Views: 22

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 ...
by Minh Ngo 4G
Sat Feb 22, 2020 11:40 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M.1
Replies: 2
Views: 22

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)...
by Minh Ngo 4G
Sat Feb 22, 2020 10:02 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing half-rxn
Replies: 3
Views: 41

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
by Minh Ngo 4G
Sat Feb 22, 2020 9:42 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing half-rxn
Replies: 3
Views: 41

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??
by Minh Ngo 4G
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: 117

Re: Purpose of Salt Bridge

To keep the electrons flowing back so that the "negative" doesn't build up on the cathode side
by Minh Ngo 4G
Thu Feb 20, 2020 9:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Half cells
Replies: 2
Views: 28

Re: Half cells

No they refer to anything. Hydrogen is just the standard use to measure E knot
by Minh Ngo 4G
Thu Feb 20, 2020 9:54 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: converting T to kelvin
Replies: 21
Views: 320

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)
by Minh Ngo 4G
Thu Feb 20, 2020 9:52 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells
Replies: 8
Views: 52

Re: Galvanic Cells

Basically to produce electricity (eg. battery)
by Minh Ngo 4G
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: 30

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
by Minh Ngo 4G
Wed Feb 12, 2020 2:57 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 4F. 11
Replies: 3
Views: 44

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
by Minh Ngo 4G
Wed Feb 12, 2020 2:47 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: P1/P2
Replies: 10
Views: 149

Re: P1/P2

Because P and V has an inverse relationship. If you increases one, one wil decreases (PV=nRT)
by Minh Ngo 4G
Wed Feb 12, 2020 2:46 pm
Forum: Calculating Work of Expansion
Topic: work in reversible reaction
Replies: 4
Views: 88

Re: work in reversible reaction

d is delta. In Calculus, it is the derivative. In this case, it is the change in volume.
by Minh Ngo 4G
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: 136

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
by Minh Ngo 4G
Wed Feb 12, 2020 2:42 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Cubic to quadratic function
Replies: 4
Views: 96

Re: Cubic to quadratic function

We are not having any cubic equation on the test. If there is, you would use an approximation.
by Minh Ngo 4G
Sat Feb 08, 2020 5:17 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 4J.5
Replies: 2
Views: 53

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...
by Minh Ngo 4G
Sat Feb 08, 2020 4:27 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 4J.3 part b
Replies: 1
Views: 19

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...
by Minh Ngo 4G
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: 37

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?
by Minh Ngo 4G
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: 41

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'...
by Minh Ngo 4G
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: 37

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?
by Minh Ngo 4G
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: 14

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
by Minh Ngo 4G
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: 91

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
by Minh Ngo 4G
Tue Feb 04, 2020 9:29 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: R vs C
Replies: 2
Views: 26

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.
by Minh Ngo 4G
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: 23

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.
by Minh Ngo 4G
Tue Feb 04, 2020 9:24 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Extensive Property
Replies: 4
Views: 35

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
by Minh Ngo 4G
Sun Feb 02, 2020 11:32 pm
Forum: Calculating Work of Expansion
Topic: 4.7 answer
Replies: 1
Views: 49

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 ...
by Minh Ngo 4G
Sat Feb 01, 2020 5:31 pm
Forum: Calculating Work of Expansion
Topic: Gas constant
Replies: 5
Views: 40

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'...
by Minh Ngo 4G
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: 50

Re: Enthalpies

Standard enthalpies of formation is when all the R are in their most stable state, forming P
by Minh Ngo 4G
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: 54

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...
by Minh Ngo 4G
Tue Jan 28, 2020 11:39 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: System vs Surroundings
Replies: 14
Views: 596

Re: System vs Surroundings

System is the one that you are focusing on. In most cases, it is the chemical rxn
by Minh Ngo 4G
Tue Jan 28, 2020 11:38 pm
Forum: Phase Changes & Related Calculations
Topic: steam at 100ºC burn worse
Replies: 7
Views: 377

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
by Minh Ngo 4G
Tue Jan 28, 2020 11:36 pm
Forum: Phase Changes & Related Calculations
Topic: Phase change and temp
Replies: 8
Views: 86

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
by Minh Ngo 4G
Tue Jan 28, 2020 11:35 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Heat Supplied to a system
Replies: 6
Views: 81

Re: Heat Supplied to a system

You need the mass to use q=mc(delta)T
by Minh Ngo 4G
Tue Jan 28, 2020 11:34 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Order of homework for Thermochem unit
Replies: 6
Views: 66

Re: Order of homework for Thermochem unit

I think right now it is 4C and 4E
by Minh Ngo 4G
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: 143

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...
by Minh Ngo 4G
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: 143

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?
by Minh Ngo 4G
Wed Jan 22, 2020 12:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Determining pH
Replies: 3
Views: 29

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...
by Minh Ngo 4G
Wed Jan 22, 2020 10:44 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Determining pH
Replies: 3
Views: 29

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 ...
by Minh Ngo 4G
Tue Jan 21, 2020 10:21 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Sig Figs for pH/pOH
Replies: 7
Views: 58

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.
by Minh Ngo 4G
Tue Jan 21, 2020 10:19 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: X was ignored
Replies: 27
Views: 204

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
by Minh Ngo 4G
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: 244

Re: Le Chatelier's Principle

When something is disturbing your chemical equilibrium and you want to see what happen next
by Minh Ngo 4G
Tue Jan 21, 2020 10:17 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction Q
Replies: 7
Views: 74

Re: Reaction Q

Reaction Quotient, Q, tells us the direction the rxn will shift in order to achieve equilibrium
by Minh Ngo 4G
Tue Jan 21, 2020 10:16 am
Forum: Ideal Gases
Topic: Kc vs Kp
Replies: 43
Views: 512

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
by Minh Ngo 4G
Sat Jan 18, 2020 1:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6E.1
Replies: 1
Views: 32

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?
by Minh Ngo 4G
Fri Jan 17, 2020 12:16 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.9
Replies: 3
Views: 114

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
by Minh Ngo 4G
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: 627

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...
by Minh Ngo 4G
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: 64

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.
by Minh Ngo 4G
Tue Jan 14, 2020 2:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Strong Acids/Bases
Replies: 4
Views: 38

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...
by Minh Ngo 4G
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: 50

Re: Which liquids to use

Only use aqueous and gas for K. You probably misunderstood aqueous for liquid.
by Minh Ngo 4G
Tue Jan 14, 2020 2:32 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Expansion
Replies: 5
Views: 36

Re: Expansion

It would make the rxn shifts to one way or another but K is remains unchanged
by Minh Ngo 4G
Tue Jan 07, 2020 11:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs K
Replies: 13
Views: 152

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
by Minh Ngo 4G
Tue Jan 07, 2020 11:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook example 5H.1
Replies: 2
Views: 28

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
by Minh Ngo 4G
Tue Jan 07, 2020 3:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant for Solids/Gases
Replies: 5
Views: 65

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
by Minh Ngo 4G
Tue Jan 07, 2020 2:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Very Large K
Replies: 12
Views: 173

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
by Minh Ngo 4G
Tue Jan 07, 2020 2:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Writing expression for K
Replies: 5
Views: 81

Re: Writing expression for K

If everything is gas then you use P but otherwise, use concentration […]
by Minh Ngo 4G
Thu Dec 05, 2019 3:05 am
Forum: Bronsted Acids & Bases
Topic: Relative strength of base?
Replies: 3
Views: 51

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...
by Minh Ngo 4G
Wed Dec 04, 2019 10:53 pm
Forum: Bronsted Acids & Bases
Topic: Relative strength of base?
Replies: 3
Views: 51

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?
by Minh Ngo 4G
Wed Dec 04, 2019 10:50 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid Strength
Replies: 5
Views: 85

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...)
by Minh Ngo 4G
Wed Dec 04, 2019 10:49 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1E.5 part d
Replies: 1
Views: 97

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...
by Minh Ngo 4G
Tue Dec 03, 2019 1:14 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: 6C.21
Replies: 2
Views: 68

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?
by Minh Ngo 4G
Mon Dec 02, 2019 11:36 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Anion stability
Replies: 6
Views: 92

Re: Anion stability

Usually the more resonance it has the more stable it is since electrons are "floating" around.
by Minh Ngo 4G
Mon Dec 02, 2019 11:34 pm
Forum: Conjugate Acids & Bases
Topic: how to figure out?
Replies: 12
Views: 218

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
by Minh Ngo 4G
Mon Dec 02, 2019 11:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Formal Charge and its effect on Shape
Replies: 3
Views: 37

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.
by Minh Ngo 4G
Mon Dec 02, 2019 11:28 pm
Forum: Bronsted Acids & Bases
Topic: strong v weak acids
Replies: 8
Views: 105

Re: strong v weak acids

It would be a smart move to do so!
by Minh Ngo 4G
Mon Dec 02, 2019 11:24 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Electronegativity and acid strength
Replies: 5
Views: 73

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...
by Minh Ngo 4G
Thu Nov 28, 2019 11:20 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid Strength
Replies: 6
Views: 103

Re: Acid Strength

I think memorization is the best way
by Minh Ngo 4G
Thu Nov 28, 2019 11:19 pm
Forum: Bronsted Acids & Bases
Topic: 6A9
Replies: 2
Views: 45

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
by Minh Ngo 4G
Thu Nov 28, 2019 11:17 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Lewis Acid/Base
Replies: 5
Views: 52

Re: Lewis Acid/Base

Lewis acid is a compound that accepts electrons while lewis base donates electron
by Minh Ngo 4G
Thu Nov 28, 2019 11:15 pm
Forum: Hybridization
Topic: Sigma and Pi bonds
Replies: 7
Views: 98

Re: Sigma and Pi bonds

Single bond: 1 sigma
Double: 1 sigma and 1 pi
Triple: 1 sigma and 2 pi
by Minh Ngo 4G
Thu Nov 28, 2019 11:14 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Bronsted Acid/Base
Replies: 4
Views: 48

Re: Bronsted Acid/Base

Bronsted acid is a compound that donates H+ in solution while Bronsted base is a compound that accepts the H+
by Minh Ngo 4G
Sat Nov 23, 2019 11:20 pm
Forum: Naming
Topic: 9C.3
Replies: 2
Views: 67

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?
by Minh Ngo 4G
Fri Nov 22, 2019 4:30 pm
Forum: Coordinate Covalent Bonds
Topic: Coordinate covalent bonds
Replies: 7
Views: 209

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
by Minh Ngo 4G
Fri Nov 22, 2019 4:29 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Acids
Replies: 6
Views: 77

Re: Acids

Whether it dissociate completely in water or not. Strong acid theoretically would dissociate 100% in water
by Minh Ngo 4G
Fri Nov 22, 2019 4:28 pm
Forum: Lewis Structures
Topic: Cis- vs Trans- bonds
Replies: 5
Views: 98

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
by Minh Ngo 4G
Fri Nov 22, 2019 4:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bent v. angular
Replies: 20
Views: 387

Re: bent v. angular

They are the same shape
by Minh Ngo 4G
Fri Nov 22, 2019 4:25 pm
Forum: Hybridization
Topic: hybridizing d orbitals
Replies: 7
Views: 78

Re: hybridizing d orbitals

Sp3d
by Minh Ngo 4G
Fri Nov 15, 2019 6:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.29 B
Replies: 1
Views: 28

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...
by Minh Ngo 4G
Fri Nov 15, 2019 5:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.25 part a
Replies: 1
Views: 37

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...
by Minh Ngo 4G
Fri Nov 15, 2019 5:37 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.21 a & d
Replies: 2
Views: 30

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...
by Minh Ngo 4G
Fri Nov 15, 2019 5:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.21 a & d
Replies: 2
Views: 30

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.

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