Search found 133 matches
- Sat Mar 14, 2020 9:48 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: k
- Replies: 36
- Views: 1705
Re: k
if concentration is kept constant, then yes, a larger k results in a faster rate
- Sat Mar 14, 2020 9:39 am
- Forum: Second Order Reactions
- Topic: Third Order Reactions [ENDORSED]
- Replies: 9
- Views: 768
Re: Third Order Reactions [ENDORSED]
I'm pretty sure third order reactions won't be on the exam.
- Sat Mar 14, 2020 9:38 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Endgame 2D
- Replies: 3
- Views: 343
Re: Endgame 2D
Maybe double check the numbers you're using again? when I do 0.15*-2*96485/(8.314*298) I get the right answer
- Sat Mar 14, 2020 9:01 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram
- Replies: 11
- Views: 763
Re: Cell Diagram
That's what I do lmao
- Sat Mar 14, 2020 9:01 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: 7C.11 c)
- Replies: 2
- Views: 217
Re: 7C.11 c)
the rate constant is a tool used to relate concentrations to the rate of reaction, and as such, is not affected by the concentrations.
- Sat Mar 14, 2020 8:52 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Concentration Cell
- Replies: 3
- Views: 261
Re: Concentration Cell
Yes. The anode is the side that is oxidized, and the side with lower concentration always receives electrons.
- Sat Mar 14, 2020 8:50 am
- Forum: First Order Reactions
- Topic: k versus k prime
- Replies: 6
- Views: 601
Re: k versus k prime
k' is a constant generally used for the reverse reaction rate. It is similar to the concept of products over reactants, since the equation divides the rate at which products are formed over the rate at which reactants are formed.
- Sat Mar 14, 2020 8:45 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Fast Step
- Replies: 1
- Views: 183
Re: Fast Step
This is because of the bottleneck effect. for example, if you have a reaction that goes through steps a, b, and c in order, with B as the slowest step, then a bottleneck will occur. Basically, the original reactants will continually be processed through step a, but step b will cause for a buildup of...
- Sat Mar 14, 2020 8:36 am
- Forum: First Order Reactions
- Topic: Pseudo First-Order Reaction?
- Replies: 2
- Views: 255
Re: Pseudo First-Order Reaction?
Basically, if the concentration of one reactant species is constant, then the rate law of rate = k [a][b] can be simplified to just rate = k' [a] where b is just assumed to be a constant. However, if the concentration of b is not much higher than a, or some other mechanism where the concentration of...
- Sat Mar 14, 2020 8:34 am
- Forum: First Order Reactions
- Topic: 7B.1
- Replies: 1
- Views: 194
Re: 7B.1
You should just be able to plug values into [A]_t = [A]_0 * e^(-kt). using 20 mg, k = 7.6*10^-3 and t = 300 yields ~2 mg
- Sat Mar 14, 2020 8:26 am
- Forum: *Enzyme Kinetics
- Topic: Bottleneck
- Replies: 2
- Views: 416
Re: Bottleneck
No, it only describes a concept in reaction rate and kinetics, but it doesn't change K at equilibrium. It may change how long it takes for a reaction to get to equilibrium however.
- Fri Mar 13, 2020 11:41 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: HW 7D.5
- Replies: 1
- Views: 170
Re: HW 7D.5
first, you find the frequency factor by plugging all of the given values and constants into the Arrhenius equation, and then you solve for k by plugging everything into the equation again except changing T.
- Fri Mar 13, 2020 11:39 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Calculations using Nernst Eq.
- Replies: 2
- Views: 266
Re: Calculations using Nernst Eq.
the basic form of a natural log is ln(x) = y where e^y = x. From this, once you isolate the natural log, in order to find the concentrations inside the log (x), you should use this identity by setting both sides as exponents of the constant e
- Fri Mar 13, 2020 11:36 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Endgame 1a
- Replies: 5
- Views: 528
Re: Endgame 1a
anode is always oxidized, and the side with lower concentration will always be oxidized.
- Fri Mar 13, 2020 11:35 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Endgame 5 and 7
- Replies: 2
- Views: 282
Re: Endgame 5 and 7
You can add them in 5 because they're part of a cathode anode system, but standard Ecell is not a state function in either case.
- Fri Mar 13, 2020 11:29 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Collision theory
- Replies: 2
- Views: 189
Re: Collision theory
Based on the review stuff we've had, I'd expect one or two conceptual questions or something to do with the Arrhenius equation to be on it.
- Fri Mar 13, 2020 11:29 pm
- Forum: Balancing Redox Reactions
- Topic: QD3 Midterm
- Replies: 5
- Views: 457
Re: QD3 Midterm
Since pH is higher than the pKa, the acid will dissociate into its conjugate base and H+, and so its conjugate base will have a charge of -1.
- Fri Mar 13, 2020 11:26 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Temperature and Kinetics
- Replies: 3
- Views: 272
Re: Temperature and Kinetics
An increase in temperature is equal to an increase in kinetic speed and so would increase the collisions of the molecules. This increases the reaction rate. Besides this it shouldn't affect the catalyst, unless the catalyst is something that can be denatured by higher temperatures or something else ...
- Fri Mar 13, 2020 11:25 pm
- Forum: First Order Reactions
- Topic: Units
- Replies: 2
- Views: 263
Re: Units
The units for the rate of reaction are M/s. Accordingly, the units for the rate constant is dependent on the units of the reactant species, so where there is only one reactant species, the rate constant is /s for first order reactions and 1/M*s for second order reactions.
- Fri Mar 13, 2020 11:20 pm
- Forum: First Order Reactions
- Topic: 7A.15
- Replies: 1
- Views: 206
Re: 7A.15
To find the order, you have to use the equation rate = k [A]^x[B]^y[C]^z. I would start by comparing experiments 1 and 4 where A^x and B^y would be constant, so the resulting difference would be due to C^z, so you'd be able to solve for z. From there I would compare 1 and 2, where B^y is constant so...
- Thu Mar 12, 2020 10:36 pm
- Forum: Balancing Redox Reactions
- Topic: Determing balanced rxns for a basic solution
- Replies: 5
- Views: 464
Re: Determing balanced rxns for a basic solution
The method your TA showed you does work, although it may be slightly slower than the normal method.
- Thu Mar 12, 2020 10:35 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Week 10 Review Problem
- Replies: 2
- Views: 184
Re: Week 10 Review Problem
Cell potential does not depend on the moles of a single half reaction, but rather on the redox reaction as a whole
- Thu Mar 12, 2020 10:35 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: K
- Replies: 3
- Views: 245
Re: K
it doesn't have to be M/s, as it depends on the order of the reaction. It is a simple constant that relates the rate of reaction to the concentration of reactants, and so the units come from changing one to the other.
- Thu Mar 12, 2020 10:34 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Homework 7E3
- Replies: 2
- Views: 208
Re: Homework 7E3
You are able to do exactly this, although it would be more efficient, albeit slightly more complicated, if you use 75/125 for the activation energy.
- Thu Mar 12, 2020 9:03 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Review Problem for Week 10 #5
- Replies: 3
- Views: 286
Re: Review Problem for Week 10 #5
you'll almost always get delta G formation in a problem, but its usually zero for molecules that are already in their lowest energy states, such as diatomic noble gases.
- Thu Mar 12, 2020 9:01 pm
- Forum: General Rate Laws
- Topic: Natural Log Rate Order
- Replies: 4
- Views: 369
Re: Natural Log Rate Order
What do you mean natural logs? I'm just assuming here, but if you're talking about the linear graph of ln(A) and time t, then yes. A reaction that has a linear graph between lnA and t is first order
- Thu Mar 12, 2020 8:59 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2 Answers
- Replies: 1
- Views: 143
Re: Test 2 Answers
1G,1H,1I Discussion, Echem Review
If you search the above post and look for one posted by chem_mod, it'll show up
If you search the above post and look for one posted by chem_mod, it'll show up
- Thu Mar 12, 2020 8:58 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Rate Constant and Shorter Half Life
- Replies: 5
- Views: 684
Re: Rate Constant and Shorter Half Life
The half life is the amount of time for half the reaction to occur. If the reaction rate is higher, it means the reaction happens faster, so then the amount of time to get to half of the final state would be shorter.
- Thu Mar 12, 2020 7:01 pm
- Forum: General Science Questions
- Topic: Study guide
- Replies: 2
- Views: 281
Re: Study guide
If you're talking about this question:Calculate the reaction enthalpy for the synthesis of hydrogen bromide gas, H2(g) + Br2(l) → 2 HBr(g), from the following data - you know that enthalpies of reaction equations can be added together, multiplied, and subtracted.
- Thu Mar 12, 2020 6:58 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Lavelle's Review Slides
- Replies: 1
- Views: 163
Re: Lavelle's Review Slides
If you algebraically solve for x, you can cancel out x on both sides of the division equation on the right side, leaving you with 10 = 2/x, where x would equal 0.2
- Thu Mar 12, 2020 6:55 pm
- Forum: Second Order Reactions
- Topic: 7B.17
- Replies: 2
- Views: 265
Re: 7B.17
Plug in the values into the equation 1/[A] = kt + 1/[A]0
- Thu Mar 12, 2020 6:53 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: End of focus question 7.25
- Replies: 1
- Views: 162
Re: End of focus question 7.25
Frogs are cold blooded, so that, even with a great difference in temperature, since their own body temperatures won't compensate for a very cold environment, this reaction still has to occur for them to have vision, and so a reaction rate that has as small of a difference as possible would be evolut...
- Thu Mar 12, 2020 6:49 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing the redox rxn in an acidic solution
- Replies: 5
- Views: 362
Re: Balancing the redox rxn in an acidic solution
Divide it into the partial reactions, where Cl is reduced and O2 is oxidized
- Thu Mar 12, 2020 6:48 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: What was your favorite chem topic?
- Replies: 137
- Views: 13100
Re: What was your favorite chem topic?
Balancing chemical equations bc ez
- Thu Mar 12, 2020 6:47 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius Equation
- Replies: 8
- Views: 599
Re: Arrhenius Equation
The Arrhenius equation basically just relates the rate constant to temperature and the activation energy of the reaction.
- Thu Mar 12, 2020 6:45 pm
- Forum: General Rate Laws
- Topic: Integrated vs. Differentiated
- Replies: 1
- Views: 153
Re: Integrated vs. Differentiated
We don't need to know how to derive or integrate rate laws. Both measure the rate of a reaction, but a differential rate law relates this to the concentration of a species in the reaction while an integrated rate law relates this to an amount of time.
- Thu Mar 12, 2020 6:42 pm
- Forum: General Rate Laws
- Topic: Rate-determining step
- Replies: 7
- Views: 599
Re: Rate-determining step
Identifying the rate limiting step can be proposed / guessed from the reaction rate equation. Depending on the question, it may also be given in the problem itself.
- Thu Mar 12, 2020 6:39 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: 7E.7
- Replies: 2
- Views: 240
Re: 7E.7
The different pathway may have a lower activation energy, but not necessarily. A different pathway can be a completely different set of sub steps per reaction that happen when a catalyst is added.
- Thu Mar 12, 2020 6:38 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Collision Theory, Mean Relative Speed, Transition State Theory
- Replies: 1
- Views: 164
Re: Collision Theory, Mean Relative Speed, Transition State Theory
We don't need to know the equations associated with collision theory, but you should have a strong conceptual understanding.
- Thu Mar 12, 2020 6:38 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Calculating Gibbs free energy of 1/2 rxn
- Replies: 3
- Views: 328
Re: Calculating Gibbs free energy of 1/2 rxn
Your units are fine, but I'm pretty sure n = 2, since there is a transfer of two electrons.
- Thu Mar 12, 2020 6:37 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Pseudo first/second order
- Replies: 2
- Views: 172
Re: Pseudo first/second order
A pseudo first or second order reaction is one that is not naturally first or second order with regard to that reactant, but, if another reactant has an relatively much larger concentration, it can be simplified to a pseudo-_____ order. You'd have to get a description of the actual experimental proc...
- Thu Mar 12, 2020 6:33 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Last Q&A question
- Replies: 1
- Views: 146
Re: Last Q&A question
I'm not sure where to find the question, but as for determining the rate limiting step, depending on the reaction rate equation, we can propose / guess which step of the reaction is the slowest, so long as it conforms to the reaction rate equation.
- Thu Mar 12, 2020 6:30 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Concentration cell question
- Replies: 3
- Views: 303
Re: Concentration cell question
Plugging the values given into the equation, E = -RT/nF *ln([Anode] / [Cathode]), we can find the concentration of the anode solution. We can also figure out part b from this problem through the same equation, where adding water to the cathode solution reduces cathode concentration, and halving the ...
- Thu Mar 12, 2020 6:27 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Solving for the equilibrium constant
- Replies: 3
- Views: 407
Re: Solving for the equilibrium constant
Your work looks right to me. Where is this problem from?
- Thu Mar 12, 2020 6:08 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle
- Replies: 4
- Views: 442
Re: Le Chatelier's Principle
If you still don't understand Le Chatelier's principle from the textbook's description, you can go to khan academy and try looking at some of his videos, and here's a youtube lecturer I find very helpful. https://www.youtube.com/watch?v=PciV_Wuh9V8
- Thu Mar 12, 2020 6:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Topics
- Replies: 10
- Views: 875
Re: Final Topics
From what I remember from lecture, I think Lavelle said that the final is cumulative
- Thu Mar 12, 2020 5:38 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: q and delta H
- Replies: 4
- Views: 452
Re: q and delta H
heat transferred is equal to enthalpy when pressure is constant.
- Thu Mar 12, 2020 4:49 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: activation energy units
- Replies: 3
- Views: 531
Re: activation energy units
Activation energy does not depend on the number of moles. If the number of moles goes up, then total energy goes up, as evidenced by the activation energy, but activation energy itself does not have anything to do with it.
- Thu Mar 12, 2020 4:48 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Slow step of reaction?
- Replies: 5
- Views: 436
Re: Slow step of reaction?
depending on a reaction, you may be able to guess what the slow step is just by looking at its chemical reaction. The slow step of an overall reaction is usually determined experimentally.
- Thu Mar 12, 2020 4:44 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: comparing rates
- Replies: 3
- Views: 269
Re: comparing rates
Yes, for each mole of one reactant species consumed, you'll get one mole of any product.
- Thu Mar 12, 2020 4:32 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Question 5 UA Worksheet
- Replies: 1
- Views: 250
Re: Question 5 UA Worksheet
Which worksheet is this?
- Thu Mar 12, 2020 4:29 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius Equation
- Replies: 3
- Views: 259
Re: Arrhenius Equation
There are a variety of problems where you can use the rate constant, such as when you have information about two of the following three, and are asked to find the third: rate constant, temperature, and activation energy of a reaction. Activation energy may be given.
- Thu Mar 12, 2020 4:10 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: rates
- Replies: 2
- Views: 218
Re: rates
The rate of reaction is how quickly a reaction proceeds, or how much concentration of reactant(s) is consumed in some period of time. The rate constant is a constant, differing between different reactions, that relates the current concentration of reactants to the rate of reaction
- Thu Mar 12, 2020 2:56 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4.17
- Replies: 2
- Views: 341
Re: 4.17
given the initial .030 mols of SO2 and O2, there should be 0.030 moles of SO3 and 0.015 moles of O2 remaining after the reaction goes to completion, since SO2 is the limiting reactant. The final amount of gas is the amount of O2 added with the newly created SO3.
- Thu Mar 12, 2020 2:52 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 6.43 questions
- Replies: 2
- Views: 231
Re: 6.43 questions
Standard just means that the reaction occurs at 25 degrees C and 1 atm. It's sometimes referred to as STP, or standard temperature and pressure.
- Thu Mar 12, 2020 2:51 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: reaction profiles
- Replies: 3
- Views: 273
Re: reaction profiles
A reaction profile is a diagram that shows the change in potential energy over a reaction pathway / time of a reaction. It will normally go up, reaching a climax, before falling to either a higher or lower energy level than when it started.
- Thu Mar 12, 2020 2:49 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Collision Frequency
- Replies: 3
- Views: 232
Re: Collision Frequency
I think we do need to understand it since I remember Lavelle talking about it in lecture.
- Thu Mar 12, 2020 2:48 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius equation
- Replies: 3
- Views: 338
Re: Arrhenius equation
The arrhenius equation relates the temperature to the rate of reaction. It can be written as k = Ae^(-E_a/RT)
- Sat Feb 01, 2020 9:01 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: example 4A.1
- Replies: 1
- Views: 88
Re: example 4A.1
The answer is already in joules when you plug it into the equation. Writing the answer either way works, as long as you make sure that it is clear what the direction of work is.
- Sat Feb 01, 2020 8:58 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: 4A. 5 Isothermic VS. Reversible
- Replies: 2
- Views: 109
Re: 4A. 5 Isothermic VS. Reversible
They describe two different properties of an expansion. Isothermic means that the gas has a constant temperature. A reversible expansion means one where the outside pressure is constant. A reversible expansion does more work in the case of that question.
- Sat Feb 01, 2020 8:55 pm
- Forum: Calculating Work of Expansion
- Topic: External Pressure in Reversible Expansion
- Replies: 1
- Views: 79
Re: External Pressure in Reversible Expansion
For example, you can have a reversible gas pump to constantly change pressure during a reaction.
- Sat Feb 01, 2020 8:53 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Textbook question 4C.3
- Replies: 3
- Views: 177
Re: Textbook question 4C.3
I got the same answers as you did, and the answer key looks like it isn't accurate.
- Sat Feb 01, 2020 8:41 pm
- Forum: Calculating Work of Expansion
- Topic: Reversible and Irreversible
- Replies: 5
- Views: 219
Re: Reversible and Irreversible
From our textbook:"in thermodynamics, a reversible process is one that can be reversed by an infi- nitely small change in a variable (an “infinitesimal” change). For example, if the external pressure exactly matches the pressure of the gas in the system, then the piston moves in neither directi...
- Sun Jan 26, 2020 11:27 pm
- Forum: Phase Changes & Related Calculations
- Topic: ∆H
- Replies: 17
- Views: 696
Re: ∆H
No, you can touch it.
- Sun Jan 26, 2020 11:25 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Practice Test
- Replies: 2
- Views: 140
Re: Practice Test
Magic Eight Ball says... Yes, Chemcomm always has practice tests.
- Sun Jan 26, 2020 11:24 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4A Thinking Point
- Replies: 2
- Views: 123
Re: 4A Thinking Point
You could use it to charge another battery in the same loop, leaving it to discharge through a light when the first battery doesn't have any electric potential left.
- Sun Jan 26, 2020 11:23 pm
- Forum: Calculating Work of Expansion
- Topic: equipartition theorem
- Replies: 2
- Views: 111
Re: equipartition theorem
Magic eight ball says... ¯\_(ツ)_/¯.
- Sun Jan 26, 2020 11:22 pm
- Forum: Phase Changes & Related Calculations
- Topic: Differentiating (q) and (w)
- Replies: 4
- Views: 200
Re: Differentiating (q) and (w)
Heat is a measure of transfer of thermal energy between two entities. Work is the amount of energy, in one form or another, that is actually used to do a certain task.
- Sun Jan 19, 2020 10:45 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Factors affecting K
- Replies: 2
- Views: 153
Re: Factors affecting K
Pressure and concentration changes will change the forward and backwards reactions at a rate that keeps the value of K, while temperature will favor one or the other, changing the value of K.
- Sun Jan 19, 2020 10:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Acids and Bases
- Replies: 2
- Views: 93
Re: Acids and Bases
Technically, it does, but it's pH is at 7, and the concentration of hydronium and hydroxide ions are extremely low, and not significant enough to affect most things
- Sun Jan 19, 2020 8:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Buffers
- Replies: 2
- Views: 158
Re: Buffers
Any questions similar to those in the homework may be asked.
- Sun Jan 19, 2020 8:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Acid Base Equilibria
- Replies: 5
- Views: 199
Re: Acid Base Equilibria
Equilibrium concepts can be applied to many parts of chemistry. Acid base is an important one among many applications.
- Sun Jan 19, 2020 8:07 pm
- Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
- Topic: Titration
- Replies: 2
- Views: 670
Re: Titration
The equivalence point can be used in conjunction with the known concentration / amount of titrant to discover the total concentration or amount of analyte.
- Sun Jan 19, 2020 8:05 pm
- Forum: Student Social/Study Group
- Topic: Week 1 Discussion
- Replies: 1
- Views: 213
- Sun Jan 12, 2020 9:11 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Response of Equilibria to Change
- Replies: 6
- Views: 166
Re: Response of Equilibria to Change
The rule of thumb is that the equilibrium will respond in a way that counteracts the change. However, this doesn't give you an accurate representation, so the best way to do so is to recalculate using equations to determine equilibrium.
- Sun Jan 12, 2020 9:08 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Calculating Q
- Replies: 16
- Views: 804
Re: Calculating Q
Q calculations are only for aqueous solutions and gases, by definition.
- Sun Jan 12, 2020 9:07 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Concentration
- Replies: 5
- Views: 152
Re: Concentration
If it is only a change in concentration, Kc won't change, the equilibrium state, at least right when the concentration is added, will be different, but it will still tend to the same equilibrium constant
- Sun Jan 12, 2020 9:06 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Reaction Direction
- Replies: 19
- Views: 1074
Re: Reaction Direction
The left and right portions are arbitrary, as, given a reversible reaction, you could switch both sides and the left directional reaction would now be the new right directional compound
- Sun Jan 12, 2020 9:05 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Partial Pressure
- Replies: 3
- Views: 160
Re: Partial Pressure
Given an ideal gas, you could use the ideal gas law to find it, but otherwise, with just the chemical compound, it would be impossible
- Sat Dec 07, 2019 4:14 pm
- Forum: Polyprotic Acids & Bases
- Topic: Ions
- Replies: 3
- Views: 332
Ions
What ions and ligands should we have memorized for the final?
- Tue Dec 03, 2019 10:28 pm
- Forum: Properties of Light
- Topic: photons
- Replies: 3
- Views: 267
Re: photons
A shorter wavelength or higher frequency = more energy. Intensity has nothing to do with the energy of the photon, but rather, it has to do with the amplitude of the wave which corresponds to the "number" of photons
- Tue Dec 03, 2019 10:26 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Equations involving P and C.
- Replies: 1
- Views: 183
Re: Equations involving P and C.
C = Wavleength * frequency is usually only used for light waves.
- Tue Dec 03, 2019 10:25 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: pOH Trends
- Replies: 3
- Views: 284
Re: pOH Trends
A higher pOH value means that the solution is more acidic, as there are magnitudes smaller amounts of OH-
Re: Naming
Practice :(. For memorizing things, especially things that are applicable in problems, it helps most just to do a ton of problems where you name things and try your best to do each without referring back to your notes.
- Tue Dec 03, 2019 10:23 pm
- Forum: Bronsted Acids & Bases
- Topic: Strategies
- Replies: 1
- Views: 181
Re: Strategies
For acid base problems, I usually just use my intuition, and it works out since you know that nitrate has a base form as a common ion
- Tue Dec 03, 2019 10:21 pm
- Forum: Naming
- Topic: Naming Compounds
- Replies: 2
- Views: 96
Re: Naming Compounds
Cyano is -cn while cyanato is -ocn
- Fri Nov 29, 2019 2:42 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: pH vs. pOH
- Replies: 17
- Views: 2552
Re: pH vs. pOH
pH measures the amount of H+ molecules in solution while pOH measures the amount of OH molecules. Basically, the higher the pH, the lower the pOH, and the more acidic. Vice versa, the higher the pOH, the lower the pH, and the more basic a solution is.
- Fri Nov 29, 2019 2:41 pm
- Forum: Hybridization
- Topic: #2F16
- Replies: 1
- Views: 160
Re: #2F16
Draw out the lewis structure of the molecule and use your knowledge of vsepr theory to see if the p-orbitals are hybridized in this case.
- Fri Nov 29, 2019 2:28 pm
- Forum: Administrative Questions and Class Announcements
- Topic: week 9! F19 1A
- Replies: 1
- Views: 196
Re: week 9! F19 1A
yoooooooooo
- Fri Nov 29, 2019 2:27 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: Intermolecular Forces
- Replies: 6
- Views: 416
Re: Intermolecular Forces
the shape, molar mass, and individual atomic electronegativity is generally what you'd need to determine IMF. IMF then determines boiling point / melting point, not the other way around. where can we find this info? I'm assuming Lavelle has touched upon this in lecture, but I can't be sure since I ...
- Fri Nov 29, 2019 2:24 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Self-test 9C.2B
- Replies: 1
- Views: 189
Re: Self-test 9C.2B
In answering the question, the hydrate isomer isn't relevant and can just be ignored.
- Fri Nov 29, 2019 2:23 pm
- Forum: Hybridization
- Topic: Hybridization for elements like S, Xe, Br, etc.
- Replies: 4
- Views: 376
Re: Hybridization for elements like S, Xe, Br, etc.
Hybridization works the same for all elements, although some are very difficult to find in a molecular form. Count the number of bonds between atoms, and then it's just the same process
- Fri Nov 29, 2019 2:21 pm
- Forum: Conjugate Acids & Bases
- Topic: 6A.3: Differentiating between acids and bases
- Replies: 2
- Views: 250
Re: 6A.3: Differentiating between acids and bases
It's relatively simple to look at the lewis structure of a molecule and see whether or not it'll donate / accept protons for some molecules.
- Tue Nov 19, 2019 7:07 pm
- Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
- Topic: Hydrogen Bonding/Pi bonds
- Replies: 11
- Views: 1649
Re: Hydrogen Bonding/Pi bonds
Hydrogen bonding is an intermolecular force, while bonds are intramolecular forces and occur inside of molecules in the form of bonds. They all rely on the same fundamental forces, but are technically different things.
- Tue Nov 19, 2019 7:06 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: Intermolecular Forces
- Replies: 6
- Views: 416
Re: Intermolecular Forces
the shape, molar mass, and individual atomic electronegativity is generally what you'd need to determine IMF. IMF then determines boiling point / melting point, not the other way around.
- Tue Nov 19, 2019 7:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Effect of lone pair repulsion on single vs double bonds
- Replies: 1
- Views: 68
Re: Effect of lone pair repulsion on single vs double bonds
They have the same repulsion effect
- Tue Nov 19, 2019 7:04 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: Boiling Points
- Replies: 7
- Views: 369
Re: Boiling Points
N2O is linear while NO2 is bent, and so the latter is a polar molecule. Due to this, NO2 IMF's are stronger, and therefore would have a higher boiling point
- Tue Nov 19, 2019 7:02 pm
- Forum: Ionic & Covalent Bonds
- Topic: Direction in anions increase in polarizability
- Replies: 3
- Views: 277
Re: Direction in anions increase in polarizability
Anions are more polarizable since they have more electrons and therefore are easier to induce a dipole in
- Fri Nov 15, 2019 8:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR SHAPES
- Replies: 1
- Views: 211
Re: VSEPR SHAPES
just googline a VSEPR chart on google images will give you a lot that'll be helpful, i.e. https://images.app.goo.gl/uBwSDjsgjDuaAWr58.
- Fri Nov 15, 2019 8:57 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: London dispersion forces and vander waals
- Replies: 5
- Views: 544
Re: London dispersion forces and vander waals
van der waals forces is a general term that includes all intermolecular forces. London dispersion forces is a type of van der waals force that occurs between nonpolar molecules with instantaneously occuring dipoles.