Search found 60 matches
- Sun Mar 17, 2019 10:51 pm
- Forum: First Order Reactions
- Topic: Slopes of a plot
- Replies: 7
- Views: 1193
Re: Slopes of a plot
The only one that isn't -k is is 2nd-order, which is just k (+k).
- Sun Mar 17, 2019 10:49 pm
- Forum: Zero Order Reactions
- Topic: Deriving Equations
- Replies: 7
- Views: 1156
Re: Deriving Equations
All are given except you might want to know different forms for 1st-order.
- Sun Mar 17, 2019 10:48 pm
- Forum: General Rate Laws
- Topic: Rate constant units
- Replies: 3
- Views: 659
Re: Rate constant units
Can you have it be moles per mL per second? Or per day?
- Sun Mar 17, 2019 12:26 am
- Forum: Balancing Redox Reactions
- Topic: calculating standard cell potential
- Replies: 5
- Views: 772
Re: calculating standard cell potential
Just remember that if you use the overall net equation for E you leave the signs and if you're adding up form had reactions etc. you have already flipped the sign so just add.
- Sun Mar 17, 2019 12:25 am
- Forum: Balancing Redox Reactions
- Topic: Balanced Half Reactions
- Replies: 5
- Views: 670
Re: Balanced Half Reactions
I think you want to balance the atoms, charge, and number of electrons all because its still a half reaction until you put it all together for the final reaction.
- Sun Mar 17, 2019 12:23 am
- Forum: Balancing Redox Reactions
- Topic: Test 2
- Replies: 2
- Views: 495
Re: Test 2
So -0.1 has more oxidizing power than -0.02, with any positive value having the strongest oxidizing power compared to these two.
- Sun Mar 17, 2019 12:16 am
- Forum: Balancing Redox Reactions
- Topic: Acidic conditions
- Replies: 3
- Views: 538
Re: Acidic conditions
Just remember that for acidic conditions you are adding H2O to whichever side needs to balance Oxygens and H+'s typically to the other. You do the same thing with basic solutions but with OH- and H2O
- Sun Mar 17, 2019 12:14 am
- Forum: Balancing Redox Reactions
- Topic: Agents
- Replies: 1
- Views: 383
Agents
I understand factually that an oxidizing agent is whatever is being reduced and a reducing agent is whatever is being oxidized. However I'm having trouble what exactly this means more conceptually. Anyone have a way to explain it that might help?
- Sun Mar 17, 2019 12:10 am
- Forum: Balancing Redox Reactions
- Topic: Balancing basic redox reactions
- Replies: 7
- Views: 835
Re: Balancing basic redox reactions
How do you know which reaction is being oxidized and which is being reduced in a question where you are only given a the final reaction? Whichever reactant has a value that is becoming less positive, as more electrons 'reduces' the number, (+7 to +5 etc.) is being reduced. Whichever reactant is get...
- Wed Mar 06, 2019 9:48 pm
- Forum: First Order Reactions
- Topic: 1/2 life
- Replies: 7
- Views: 772
Re: 1/2 life
Why is it that for only the first order it isn't dependent on the initial concentration?
- Wed Mar 06, 2019 9:46 pm
- Forum: First Order Reactions
- Topic: Exponential Curve
- Replies: 6
- Views: 628
Re: Exponential Curve
I thought on Monday he said first order rate laws would always have a linear slope? -k?
- Wed Mar 06, 2019 9:45 pm
- Forum: General Rate Laws
- Topic: Which law?
- Replies: 2
- Views: 291
Which law?
How do we know when to use each rate law? Will we have to be able to recognize it or will the question tell us?
- Wed Mar 06, 2019 9:43 pm
- Forum: General Rate Laws
- Topic: Mechanisms?
- Replies: 3
- Views: 379
Re: Mechanisms?
Check the textbook, it should be in there!
- Wed Mar 06, 2019 9:43 pm
- Forum: General Rate Laws
- Topic: Table with different Concentration
- Replies: 4
- Views: 418
Re: Table with different Concentration
It should mirror the homework so if you've been seeing that type of problem in the textbook then its likely that it could appear.
- Wed Mar 06, 2019 9:42 pm
- Forum: General Rate Laws
- Topic: Slope
- Replies: 2
- Views: 287
Slope
On Monday Professor Lavelle said that we could tell when the 1st order rate law is being used because the slope would be linear, yet today for the 2nd and 0 order rate laws, those slopes were linear as well. Did i miss something?
- Wed Mar 06, 2019 9:40 pm
- Forum: General Rate Laws
- Topic: Rate Laws 0-2
- Replies: 2
- Views: 248
Rate Laws 0-2
How can we tell when each rate law is supposed to be used? Is it related to what the variable on the y-axis is?
- Mon Feb 25, 2019 7:32 pm
- Forum: Balancing Redox Reactions
- Topic: Test #2
- Replies: 9
- Views: 883
Re: Test #2
Will he ask us any acid base questions, or is he only asking Gibbs and electrochemistry?
- Sun Feb 03, 2019 8:14 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Recognizing delta u
- Replies: 2
- Views: 260
Re: Recognizing delta u
If they mention internal energy then they are referring to delta U and you should use its associated equations.
- Sun Feb 03, 2019 8:13 pm
- Forum: Calculating Work of Expansion
- Topic: work done by vs on a system
- Replies: 5
- Views: 731
Re: work done by vs on a system
So basically what matters is if energy is being put into a system vs. is being "taken out of" a system.
- Sun Feb 03, 2019 8:11 pm
- Forum: Calculating Work of Expansion
- Topic: Equations for w
- Replies: 5
- Views: 450
Re: Equations for w
So does this mean we aren't going to have to use the integral formula to calculate anything on tests?
- Sun Feb 03, 2019 8:09 pm
- Forum: Calculating Work of Expansion
- Topic: Isolated System
- Replies: 5
- Views: 2854
Re: Isolated System
The heat of the surroundings would not be able to effect the isolated system so regardless of the surrounding heat, it doesn't matter. It will not effect the system and would not matter for calculations/the problem at large.
- Sun Feb 03, 2019 8:08 pm
- Forum: Calculating Work of Expansion
- Topic: Units for pressure
- Replies: 10
- Views: 721
Re: Units for pressure
If its ever in bar, thats more or less equivalent to atm.
- Sun Feb 03, 2019 8:07 pm
- Forum: Calculating Work of Expansion
- Topic: internal vs. external pressure
- Replies: 3
- Views: 5868
Re: internal vs. external pressure
If these two were not equal, then they would be attempting to reach a state of equilibrium (being equal). So if you had a closed system with a certain pressure on the inside and a different pressure on the outside, and you suddenly removed whatever was making the system closed rather than open, the ...
- Sun Feb 03, 2019 8:04 pm
- Forum: Calculating Work of Expansion
- Topic: Free expansion
- Replies: 3
- Views: 358
Re: Free expansion
With this free expansion, would the pressure and volume both be positive for the work equation? I get confused as to if the P is always negative or not.
- Sun Jan 20, 2019 10:40 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Lecture 1/18/19
- Replies: 1
- Views: 161
Lecture 1/18/19
Can someone explain the last example he did on Friday? Im a little confused still as to how/why NO2- was 0.15 and H3O+ was still 0
- Sun Jan 20, 2019 10:36 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Week 1 Lecture 3
- Replies: 4
- Views: 296
Re: Week 1 Lecture 3
So you can only calculate K when you already know its at equilibrium?
- Sun Jan 20, 2019 10:31 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 5%
- Replies: 5
- Views: 478
5%
How exactly does one actually test the 5% rule (if x less than 5% of initial concentration then the approximation is valid)? He always says it in lecture but hasn't actually done the math and I need to see things like that before i fully grasp them regardless of how basic i know it is.
- Sun Jan 20, 2019 8:58 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Week 1 Lecture 3
- Replies: 4
- Views: 296
Re: Week 1 Lecture 3
and furthermore, if you switch the concentrations from all being 0.1 to all being 0.2, is it still at equilibrium as all the values increased proportionally?
- Sun Jan 20, 2019 8:56 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Week 1 Lecture 3
- Replies: 4
- Views: 296
Week 1 Lecture 3
In class on 1/11/19 we did an example where we calculated K with initial concentrations at eq. being 0.1, 0.1, and 0.1. We got 100 for the K value. We then said that if P doubles (V halves) then the new initial concentration wold be 0.2, 0.2, and 0.2. We calculated the Q value for this and got 25. C...
- Sat Jan 12, 2019 9:55 pm
- Forum: Ideal Gases
- Topic: units for PV=nRT
- Replies: 5
- Views: 612
Re: units for PV=nRT
For P (partial pressure), bar and atm are used almost interchangeably as their values are apparently quite similar.
- Sat Jan 12, 2019 9:51 pm
- Forum: Ideal Gases
- Topic: K and Q
- Replies: 7
- Views: 450
Re: K and Q
K calculates the equilibrium constant (either with partial pressure P or concentration n/v) whereas Q can be use anytime and is useful in its comparison to a K value. Whether it is greater than or less than the reactions K value, dictates which direction the reaction is going and if there are more p...
- Sat Jan 12, 2019 9:49 pm
- Forum: Ideal Gases
- Topic: bar or atm
- Replies: 8
- Views: 590
Re: bar or atm
So 1 bar is roughly equivalent to 1 atm? The same holding true for, lets say, 6 bar and 6 atm?
- Sat Dec 08, 2018 9:08 pm
- Forum: Hybridization
- Topic: 4.93
- Replies: 2
- Views: 472
4.93
Why are all the Carbon atoms in 4.93 SP^3 hybridized? Don't they only have 3 regions of electron density each?
- Sat Dec 08, 2018 8:51 pm
- Forum: Administrative Questions and Class Announcements
- Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
- Replies: 118
- Views: 20766
Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Double and triple bonds count as single regions of electron density correct? Im trying to explain them to my friend and she's convinced they count as 2 and 3 respectively.
- Sat Dec 01, 2018 8:51 pm
- Forum: Hybridization
- Topic: Rating Polarity
- Replies: 3
- Views: 302
Re: Rating Polarity
HF will have greater polarity than HCL, which will in turn have greater polarity than HBR, which is more polar than HI. It corresponds directly with electronegativity as the stronger the electronegativity of an atom, the more it pulls an electron, and thus the more polar the molecule becomes.
- Sat Dec 01, 2018 8:44 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: sigma composition
- Replies: 2
- Views: 559
Re: sigma composition
When it goes down a period does it get to 3SP^3 ever? We only did examples in class that were in the second period so I'm a tad confused.
- Sat Dec 01, 2018 8:43 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: repulsion strength
- Replies: 3
- Views: 635
Re: repulsion strength
This is why when doing VSEPR if there is a linear molecule (2 bonds) and you add a lone pair it becomes bent. The repulsion from the lone pair is so strong that the bonds move closer towards each other to be away from the lone pair.
- Sat Dec 01, 2018 8:35 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Water molecules
- Replies: 9
- Views: 916
Re: Water molecules
They bond with things that have a partial negative charge as they have a partial positive charge. They will form hydrogen bonds with N, O, and F (if they have partial negative charges, which they should). H bonding holds DNA together and gives whatever it makes up higher melting and boiling points.
- Sat Dec 01, 2018 8:10 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: AXE formula
- Replies: 32
- Views: 12047
Re: AXE formula
To learn these I just made a chart, or you can write down the one posted above as it can be super helpful, and then put it all into flashcards on quilt. I studied that until i had it memorized, then, doing a bunch of problems switches the memorization from route to actual understanding.
- Sat Dec 01, 2018 8:05 pm
- Forum: Hybridization
- Topic: Regions of Electron Desnity
- Replies: 5
- Views: 455
Re: Regions of Electron Desnity
Also, regarding this, Yes, and they also count when determine electron arrangement. It is important however, to remember that lone pairs do not count when naming the shape. The lone pairs DO count when naming the shape in some instances as it can help you know what shape it is. If its just 3 bonds a...
- Sat Dec 01, 2018 8:03 pm
- Forum: Hybridization
- Topic: Regions of Electron Desnity
- Replies: 5
- Views: 455
Re: Regions of Electron Desnity
So for hybridization we count all bonding pairs and all lone pairs to get all the regions of electron density? Do we ever only count the bonding pairs?
- Sat Dec 01, 2018 7:58 pm
- Forum: Hybridization
- Topic: 2SP^3 vs. SP^3
- Replies: 6
- Views: 749
2SP^3 vs. SP^3
Is 2SP^3 always equivalent to SP^3, or just sometimes? Its when its on that level correct? All of the examples we did in class were the 2SP^3 so I'm slightly confused as to how it works for molecules above period 2.
- Sat Dec 01, 2018 7:55 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Types of intramolecular forces
- Replies: 4
- Views: 536
Re: Types of intramolecular forces
What if the molecule is polar and doesn't have hydrogen bonding?
- Tue Nov 27, 2018 4:22 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma vs. Pi
- Replies: 11
- Views: 1609
Sigma vs. Pi
Im having trouble being able to easily identify when a bond is a sigma bond vs. when its a pi bond. Does anyone have any quick and easy tips? I feel like its super simple and im just way over complicating it.
- Tue Nov 27, 2018 4:20 pm
- Forum: Lewis Structures
- Topic: Midterm question
- Replies: 8
- Views: 657
Re: Midterm question
If you didn't get your midterm after lecture last week, go to your TA and they should have it. When your TA graded it they did a pretty good job of explaining what you got wrong and can explain why you got things wrong.
- Tue Nov 27, 2018 4:17 pm
- Forum: Lewis Structures
- Topic: Complicated Lewis Structures
- Replies: 3
- Views: 334
Re: Complicated Lewis Structures
Are you referring to the [] compound's we covered in class on Monday? The coordinated compounds/bonds?
- Tue Nov 06, 2018 7:01 pm
- Forum: Ionic & Covalent Bonds
- Topic: Bond Length
- Replies: 8
- Views: 583
Re: Bond Length
So the shorter the bond,the stronger it also is?
- Tue Nov 06, 2018 7:00 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent bonds
- Replies: 3
- Views: 381
Covalent bonds
Anytime two atoms of the same type are bonded together it must be a covalent bond correct? Like in Disulfide bonds?
- Sun Nov 04, 2018 6:49 pm
- Forum: Properties of Light
- Topic: Practice Midterm 8b
- Replies: 3
- Views: 560
Re: Practice Midterm 8b
On the same question, based on the reply, what is the V we use to solve for v? Its the velocity of the electron right? I feel like im just missing something super obvious here...
- Sun Nov 04, 2018 6:30 pm
- Forum: Properties of Light
- Topic: Midterm Question 5a
- Replies: 4
- Views: 454
Re: Midterm Question 5a
They compared it to a fingerprint, an ID of sorts. Based upon the specific wavelength that is emitted/absorbed, an object (whatever it may be) can be identified.
- Sun Oct 21, 2018 6:33 pm
- Forum: Photoelectric Effect
- Topic: Work Function
- Replies: 16
- Views: 760
Re: Work Function
If the energy of the light (photons) is higher than the work function (the little symbol that looks kind of like the green lantern symbol) then its met the "threshold" and can eject an electron. The difference between the work function (threshold) and the energy from the light equates to w...
- Sun Oct 21, 2018 6:18 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: What is the equation used for?
- Replies: 9
- Views: 845
Re: What is the equation used for?
This relates to the uncertainty regarding electrons. The more we know concerning an electrons position, the less we know about its momentum and vice versa. The two things exhibit an inverse relationship toward each other. My TA made it seem like we more so had to undderstand the concepts than we had...
- Sun Oct 21, 2018 6:15 pm
- Forum: Properties of Light
- Topic: Wavelengths and frequencies
- Replies: 10
- Views: 643
Re: Wavelengths and frequencies
Honestly as long as you know the order and which is shortest and which is longest, you should be ok. I would try to learn the rough values of each differing type, but beyond that I think you should be fine.
- Sun Oct 14, 2018 8:01 pm
- Forum: Properties of Light
- Topic: Chapters 1 and 2 logisitcs
- Replies: 3
- Views: 250
Chapters 1 and 2 logisitcs
Im not sure if I've missed an obvious explanation but i'm slightly confused as to what is covered and when. I know last Monday we started chapters 1 and 2, however i'm not sure if we finished the chapters and now have new chapters assigned, or if we are still doing those chapters. Will the homework ...
- Sun Oct 14, 2018 2:33 pm
- Forum: Properties of Light
- Topic: C=Wavelength*Frequency
- Replies: 11
- Views: 3130
Re: C=Wavelength*Frequency
Does it matter if you use 2.99x10^8 or 3.00x10^8? or are they close enough that the difference is indiscernible?
- Sun Oct 14, 2018 2:31 pm
- Forum: Properties of Light
- Topic: De Broglie Equation
- Replies: 6
- Views: 428
Re: De Broglie Equation
Im slightly confused as to why Kg is the standard SI unit for mass when all of the mole conversions and problems weve been doing thus far have been in grams?
- Sun Oct 14, 2018 2:29 pm
- Forum: Properties of Light
- Topic: Colors and Frequency
- Replies: 14
- Views: 1557
Re: Colors and Frequency
And do we also need to have memorized at what values each differing type of light starts and ends?
- Sat Oct 06, 2018 10:01 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Question E.15
- Replies: 1
- Views: 132
Question E.15
Is the sulfide being referred to in question E.15 the metal that is mentioned in the question? I was confused where the Sulfide suddenly came from?
- Sat Oct 06, 2018 9:58 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing reactions tips
- Replies: 29
- Views: 2039
Re: Balancing reactions tips
Typically I do it by trial and error as wel (more or less logic-ing it out) but you can do the method from that one example he did where he got 13/2 (6.5) then multiply both side by 2
- Sat Oct 06, 2018 9:52 pm
- Forum: Empirical & Molecular Formulas
- Topic: Molecular Formula
- Replies: 12
- Views: 542
Re: Molecular Formula
How do you know which order they should go in though?