## Search found 50 matches

Tue Mar 13, 2018 7:30 pm
Forum: *Enzyme Kinetics
Topic: Temperature and rate constants
Replies: 2
Views: 295

### Re: Temperature and rate constants

Raising the temperature will induce a larger k!
Tue Mar 13, 2018 7:29 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow and Fast Steps
Replies: 2
Views: 230

### Re: Slow and Fast Steps

I think we will be required to know how to differentiate between steps and show which one is the faster/slower one!
Tue Mar 13, 2018 7:29 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Which is which k?
Replies: 4
Views: 262

### Re: Which is which k?

I think normally we would assume that k is the forward reaction? But I am not positive! They should give it in the problem on the final, though.
Tue Mar 13, 2018 7:28 pm
Forum: Zero Order Reactions
Topic: Applications
Replies: 2
Views: 299

### Applications

Does anyone know of any examples of naturally occurring, applications of zero order reactions that we should be able to recognize?

Thanks!
Tue Mar 13, 2018 7:27 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: determine K
Replies: 3
Views: 371

### Re: determine K

Because there are 3 moles of B and only one of A it should be the same process just use the equation that would include 1/3!
Tue Mar 13, 2018 7:25 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Order less than 0
Replies: 4
Views: 374

### Re: Order less than 0

Yes, an order can be negative as well as a fraction! But we mainly just focus on zero, first, and second as those are the most common, naturally occurring orders for reactions.
Tue Mar 13, 2018 7:23 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells
Replies: 2
Views: 224

### Re: Galvanic Cells

Because there are different charges in the cathode and anode, the electrons will naturally move through the conducive wire to the cathode side!

Hope this helped.
Tue Mar 13, 2018 7:20 pm
Forum: Balancing Redox Reactions
Topic: Balancing redox reactions in question 14.13
Replies: 2
Views: 191

### Re: Balancing redox reactions in question 14.13

Hi! Simply writing out the half reactions will make it a lot easier! I always make sure to write out the half-reactions that are given and make sure they cancel out electrons to become the final reaction. As Victoria stated, making sure that the electrons cancel is the easiest way to balance the rea...
Tue Mar 13, 2018 7:19 pm
Forum: Balancing Redox Reactions
Topic: EMF
Replies: 1
Views: 159

### EMF

Does anyone know whether or not we will need to be able to define the electromotive force (emf) and its use for the final? If we do, could someone please give a definition?

Thanks!!
Mon Feb 19, 2018 3:25 pm
Forum: Balancing Redox Reactions
Topic: Balancing H
Replies: 2
Views: 217

### Re: Balancing H

I think you have to add H20 to one side and H+ to the other! So if you add hydrogen ions to one side it should be H20 on the other side. There are helpful worksheets on Lavelle's website under "Redox Reactions" if you want to look at that too.
Mon Feb 19, 2018 3:24 pm
Forum: Balancing Redox Reactions
Topic: Test 2
Replies: 3
Views: 248

### Test 2

For Test 2, will we just need to know how to balance redox reactions and identify cathodes/anodes? Does anyone have a list of useful equations or concepts?
Mon Feb 19, 2018 3:18 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Molar entropy v standard entropy of formation
Replies: 3
Views: 1351

### Re: Molar entropy v standard entropy of formation

Molar entropy is only for one mole of the substance, while standard entropy is just the general entropy for the formation of the product!

Hope that helps.
Mon Feb 19, 2018 3:17 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Understand equation
Replies: 2
Views: 296

### Re: Understand equation

The equation takes into account all the moles no matter the state! So just take what you are given with the equation and the enthalpies and then subtract the sum of the reactants from the sum of the products.

Hope that helps.
Mon Feb 19, 2018 3:16 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Change in Entropy for the Surroundings vs. System
Replies: 2
Views: 303

### Re: Change in Entropy for the Surroundings vs. System

The equations are opposite for the system vs the surroundings because heat is being transferred from one to the other, so the entropies must be opposite values to reflect this.
Mon Feb 19, 2018 3:14 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: delta U for reversible [ENDORSED]
Replies: 2
Views: 227

### Re: delta U for reversible[ENDORSED]

If a system is isothermal, that means that q=0, so if the substance is reversible or irreversible, the internal energy change will still be 0-- this is because there is no change in heat!
Mon Feb 19, 2018 3:13 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: PV = nRT
Replies: 6
Views: 405

### Re: PV = nRT

You use this equation for ideal gases! If in a problem, you are given a pressure and the other variables, and it is stated that the given substance is an ideal gas, you will use this equation.

Hope this helped,
Maya
Mon Feb 19, 2018 3:12 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Practice Midterm #7
Replies: 2
Views: 167

### Re: Practice Midterm #7

Hi!

Yes, make sure you add the enthalpy for melting the ice (the phase change) for the Q of the system. That should get you the right answer!
Mon Feb 19, 2018 3:10 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Derivation of Formulas
Replies: 5
Views: 452

### Re: Derivation of Formulas

Hi Chris!

We don't need to know the derivations of the formulas, but will be expected to show why we're using certain formulas on the test. For example, with Van't Hoff's equation, it would be useful to put both of the equations that we are using.
Mon Feb 19, 2018 3:08 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isothermal system
Replies: 5
Views: 607

### Re: Isothermal system

Hi Tiffany!

Because q=0 as there is no transfer of heat or change in temp (isothermal) there will be no change in entropy of the molecules.
Mon Feb 19, 2018 3:07 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: constant pressure
Replies: 2
Views: 306

### Re: constant pressure

Hi Bella!

Usually the book or test will tell you are using a constant pressure. Unless they give another pressure, I think it's safe to assume that the pressure is constant.
Mon Feb 19, 2018 3:05 pm
Forum: Calculating Work of Expansion
Topic: irreversible work [ENDORSED]
Replies: 3
Views: 266

### Re: irreversible work[ENDORSED]

Yes you use that equation! Also remember that reversible work does more work than irreversible work, as the area underneath the curve is greater.
Sun Jan 28, 2018 10:49 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Test question [ENDORSED]
Replies: 16
Views: 887

### Test question[ENDORSED]

On the test where we were supposed to state the First Law of Thermodynamics, how specific were we supposed to get with the definition?

Thanks!
Sun Jan 28, 2018 10:48 pm
Forum: Calculating Work of Expansion
Topic: Diagram of Reversible Expansion
Replies: 3
Views: 249

### Re: Diagram of Reversible Expansion

A vacuum is a space that has no matter! For example, space is a vacuum because nothing can exist in that space. Because its pressure is lower, work will probably be done on that part of the system!
Sun Jan 28, 2018 10:47 pm
Forum: Biological Examples (*DNA Structural Transitions, etc.)
Topic: DNA Structural Transition
Replies: 2
Views: 601

### DNA Structural Transition

Can anyone explain what exactly a DNA structural transition is? And its significance to thermodynamics?
Sun Jan 28, 2018 10:46 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity [ENDORSED]
Replies: 4
Views: 265

### Heat capacity[ENDORSED]

Does anyone know if there are heat capacities we must know/memorize? Such as the heat capacity of water, etc.
Sun Jan 28, 2018 10:45 pm
Forum: Phase Changes & Related Calculations
Topic: Endothermic or Exothermic
Replies: 20
Views: 867

### Re: Endothermic or Exothermic

Condensation is exothermic! It's easy to just think of where the heat is going (gas has more heat/energy than a liquid, so the heat must be leaving the gas).
Sun Jan 28, 2018 10:44 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Universe being isolated
Replies: 3
Views: 254

### Universe being isolated

Can anyone explain why exactly the universe is an isolated system? How is it similar to a calorimeter?
Mon Jan 15, 2018 7:12 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Constant Pressure Enthalpy
Replies: 1
Views: 108

### Constant Pressure Enthalpy

Why does delta H = q when there's constant pressure?
Mon Jan 15, 2018 7:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 3
Views: 189

### Re: Hess's Law

Hi Warda!

Hess' Law is also especially helpful when you need to utilize the given reactions to come up with an unknown enthalpy. That way, you can use enthalpies that are known, rearrange the products and reactants, and solve for an unknown enthalpy.

Hope this helped!

Maya
Mon Jan 15, 2018 7:08 pm
Forum: Phase Changes & Related Calculations
Topic: reversible, isothermal expansion of a gas
Replies: 2
Views: 159

### Re: reversible, isothermal expansion of a gas

Hi Simrina!

I don't believe we need to know this! Dr. Lavelle didn't really go over using derivatives in lecture.

Hope this helped,
Maya
Mon Dec 04, 2017 9:53 pm
Forum: Naming
Topic: Order of Chemicals/Ligands
Replies: 1
Views: 112

### Order of Chemicals/Ligands

Can anyone explain the order of the ligands in naming? When you are presented with a coordination compound, what is the normal order for naming the ligands and other atoms?

Thanks!
Mon Dec 04, 2017 9:24 pm
Forum: Biological Examples
Topic: Final-- Examples
Replies: 2
Views: 404

### Final-- Examples

Does anyone know if we will be tested on the final with biological examples? As in do we need to memorize a couple in case we are tested on them? In that case, does anyone have any logical/easy way of remembering them?

Thanks!!
Tue Nov 28, 2017 8:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Converting between constants
Replies: 2
Views: 206

### Re: Converting between constants

I don't think so either! Dr. Lavelle said we wouldn't have to use the molar concentrations that much.
Tue Nov 28, 2017 8:50 pm
Forum: Dipole Moments
Topic: SiO2
Replies: 2
Views: 274

### Re: SiO2

I agree with Emily! On the midterm, I thought about it as Silicon and Oxygen having two different electronegativities, so the Silicon and Oxygen would not bond ionically. They are also from the same "side" of the periodic table, and not from two different sides like all of the other ionic ...
Sun Nov 19, 2017 9:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Naming; VSEPR
Replies: 3
Views: 306

### Re: Naming; VSEPR

The variables A and X stand for different things in the VSEPR model! Lavelle went over it in his lecture I am pretty sure, but you might be talking about some sort of exception.
Sun Nov 19, 2017 9:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 180degrees and lone pairs?
Replies: 4
Views: 275

### Re: 180degrees and lone pairs?

Yes, it could be trigonal bipyramidal! The lone pair electrons may balance each other out to make it possible.
Sun Nov 19, 2017 9:00 pm
Forum: Resonance Structures
Topic: Midterm Q8
Replies: 2
Views: 220

### Midterm Q8

Can anyone explain why exactly the HOCO compound has the Lewis structure that it does? Why is it not classified as a radical?
Sun Nov 19, 2017 8:58 pm
Forum: Hybridization
Topic: General Hybridization
Replies: 3
Views: 324

### General Hybridization

Does anyone have any useful graphics for picturing hybridization? I am trying to come up with a more general picture of hybridization, and feel like watching some sort of a video would make it easier to understand.

Thanks!
Sun Nov 19, 2017 8:57 pm
Forum: Dipole Moments
Topic: Power of Dipoles
Replies: 2
Views: 192

### Power of Dipoles

Is it possible to measure the power of a dipole moment? A.k.a. are there dipole moments that are stronger than others?

Thanks!
Maya
Sun Nov 19, 2017 8:56 pm
Forum: Resonance Structures
Topic: SO2 resonance
Replies: 2
Views: 267

### Re: SO2 resonance

I just checked also and it only says 2! Possibly the problem you are working on has the wrong answer? You might want to check the solutions manual online.
Thu Nov 02, 2017 10:16 pm
Forum: Trends in The Periodic Table
Topic: Logistics
Replies: 1
Views: 149

### Logistics

I have a question regarding trends! Does anyone have any easy ways to be able to remember the trends? Let me know if you have any tricks to remember the increasing/decreasing trends.

Thanks,
Maya
Thu Nov 02, 2017 10:15 pm
Forum: Trends in The Periodic Table
Topic: 2.67 [ENDORSED]
Replies: 2
Views: 196

### 2.67[ENDORSED]

Hey!

I have a question regarding electron affinity trends. For problem 67 part B, the question is which has the higher electron affinity: nitrogen or chlorine. The answer should be nitrogen because it is to the right of chlorine, but in the book it says the answer is chlorine. Why is this??

Help!!
Thu Nov 02, 2017 10:13 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 1.45
Replies: 2
Views: 240

### Re: 1.45

Yes exactly!! You don't have to take into account the value of the velocity itself because it is only asking for the uncertainty.

Hope this helped.
Thu Nov 02, 2017 10:12 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty Principle [ENDORSED]
Replies: 5
Views: 382

### Uncertainty Principle[ENDORSED]

Hi!!

I have a question regarding the Uncertainty principle. If given a problem where the momentum uncertainty, for example, is + or - 2, does that mean the uncertainty amount is 4? Or do you have to take into account the value of the momentum?

Thanks!
Sun Oct 22, 2017 4:54 pm
Forum: Ionic & Covalent Bonds
Topic: Chemical formula?
Replies: 5
Views: 430

### Re: Chemical formula?

Hi!

You usually will not have to find a chemical formula without any given values. Metals, gases, etc. have different characteristics that make them easier to figure out; which is listed in the book.

Hope this helped.
Sun Oct 22, 2017 4:48 pm
Forum: Electronegativity
Topic: Which atom would carry the formal charge
Replies: 3
Views: 594

### Re: Which atom would carry the formal charge

Hello!

The most electronegative atom would hold the electron as, by the definition of electronegativity, the atom holds a higher affinity for taking electrons.

Hope this makes sense, and good luck.
Fri Oct 13, 2017 6:54 pm
Forum: Properties of Light
Topic: Balmer vs Lyman Series [ENDORSED]
Replies: 3
Views: 313

### Re: Balmer vs Lyman Series[ENDORSED]

Hey! The Lyman series corresponds to n=1 because it refers to wavelengths that start at a given energy level and end at 1 (2-1, 1-1, 3-1). The same goes for the Balmer series but with n=2. As for knowing which series to use, the problem will normally state which series is most appropriate! Hope this...
Fri Oct 13, 2017 6:51 pm
Forum: Properties of Light
Topic: Converting Units [ENDORSED]
Replies: 11
Views: 777

### Re: Converting Units[ENDORSED]

I agree with the above as well! Sometimes it is easier to see the answer in meters (the SI unit), however in some cases it is more useful to see the answer in the closest unit. For example, if the closest thing is a nanometer, you would be able to see and compare the answer to other wavelengths.
Fri Oct 06, 2017 2:23 pm
Forum: Balancing Chemical Reactions
Topic: Percent yield [ENDORSED]
Replies: 6
Views: 691

### Re: Percent yield[ENDORSED]

Hi Jelci! To calculate percent yield, all you have to do is divide the actual yield by theoretical yield. This will give you a decimal value, which you can then multiply by 100 to get the percent value. To think about this in an easier way just consider how much of your theoretical yield you have pr...
Fri Oct 06, 2017 2:21 pm
Forum: SI Units, Unit Conversions
Topic: Significant Figures [ENDORSED]
Replies: 9
Views: 1147

### Re: Significant Figures[ENDORSED]

Hello! One very easy way to go about sig figs is to simply look at the amount of sig figs in the value that is given. For example, if you are given a problem of combustion that begins with 7.00 g of butane gas, the amount of sig figs for the answer will most likely be 3-- as there are 3 sig figs in ...