## Search found 60 matches

Sun Mar 17, 2019 10:51 pm
Forum: First Order Reactions
Topic: Slopes of a plot
Replies: 7
Views: 726

### 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: 669

### 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: 345

### 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: 359

### 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: 414

### 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: 298

### 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: 328

### 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: 242

### 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: 487

### 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: 343

### 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: 247

### 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: 156

### 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: 160

### 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: 178

### 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: 145

### 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: 113

### 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: 428

### 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: 138

### 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: 279

### 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: 230

### 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: 2586

### 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: 312

### 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: 1432

### 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: 194

### 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: 70

### 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: 190

### 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: 255

### 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: 190

### 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: 190

### 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: 242

### 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: 312

### 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: 310

### 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: 342

### 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: 13695

### 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: 176

### 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: 380

### 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: 400

### 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: 498

### 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: 5689

### 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: 195

### 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: 195

### 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: 274

### 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: 227

### 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: 833

### 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: 330

### 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: 75

### 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: 328

### 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: 195

### 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: 305

### 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: 240

### 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: 375

### 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: 451

### 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: 370

### 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: 162

### 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: 850

### 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: 234

### 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: 875

### 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: 100

### 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: 1243

### 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: 248

### Re: Molecular Formula

How do you know which order they should go in though?