## Search found 62 matches

Fri Mar 15, 2019 1:33 pm
Forum: General Rate Laws
Topic: Final Equations
Replies: 4
Views: 157

### Re: Final Equations

memorize this (it hasnt been on the sheet)
[A]t=[A]o -kt
Fri Mar 15, 2019 1:28 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: When to use Quadratic equation
Replies: 10
Views: 1159

### Re: When to use Quadratic equation

Does anyone have an example of this either from a book or a review session that goes step by step? thank u
Fri Mar 15, 2019 1:27 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Buffers
Replies: 4
Views: 384

### Re: Buffers

Yes the acid/base comes from the salt!
Fri Mar 15, 2019 1:26 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: strong and weak acids
Replies: 5
Views: 408

### Re: strong and weak acids

the more H3O+ ions there are the stronger the acid, so lower H3O+ ions means higher pH. (It's completely based on the H3O+ ions)
Fri Mar 15, 2019 1:25 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Units
Replies: 6
Views: 463

### Re: Units

No units for any of the equilibrium constants.
Fri Mar 15, 2019 1:22 pm
Forum: Ideal Gases
Topic: atm vs. bar?
Replies: 23
Views: 752

### Re: atm vs. bar?

when calculating for R just use the 8.314 value
Fri Mar 15, 2019 1:20 pm
Forum: Ideal Gases
Replies: 2
Views: 149

the C- is a 50% but it depends on the class average that it is scaled to that.
Fri Mar 15, 2019 1:18 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: instantaneous and unique rate
Replies: 6
Views: 575

### Re: instantaneous and unique rate

The unique rate has more to do with their relationship with each other like a product with a reactant.
The instantaneous rate is the tangent line when their is a change.
Fri Mar 15, 2019 1:16 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Initial Rates given in mmmol
Replies: 2
Views: 307

### Re: Initial Rates given in mmmol

i always convert back to mol because that's like the official units
Fri Mar 15, 2019 1:15 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Units of k
Replies: 7
Views: 418

### Re: Units of k

they are different depending on the order.

so the 1st only has s^-1
2nd: mol*L^-1*s^-1
3rd: mol^2 *L^-2 *s^-2
Fri Mar 15, 2019 1:13 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Rate vs. Initial Rate
Replies: 4
Views: 429

### Re: Rate vs. Initial Rate

initial rate is the one thats usually given but if the rate in general is given to you then you use the equation to do (k*any concentration that you are at) , versus initial has to do with the concentration in the beginning.
Wed Feb 20, 2019 1:48 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: What is pKa and Ka exactly?
Replies: 11
Views: 8944

### Re: What is pKa and Ka exactly?

the larger the Ka, the stronger the acid.
Wed Feb 20, 2019 1:47 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Autoprotolysis
Replies: 4
Views: 393

### Re: Autoprotolysis

it just means that in this example water can be an acid and a base. With this said, some of them would give away their H+ and become OH- and the one receiving the proton would become H3O+ .
Wed Feb 20, 2019 1:45 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ignoring x validity
Replies: 6
Views: 454

### Re: ignoring x validity

But are they going to give us a problem that is x^3?
Wed Feb 20, 2019 1:45 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Direction of a Reaction
Replies: 8
Views: 453

### Re: Direction of a Reaction

if Q>K , the reaction moves to the reactants.
if Q<K, the reaction moves to the products
Wed Feb 20, 2019 1:41 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 11
Views: 924

### Re: Le Chatelier's Principle

how do you calculate the partial pressure? and how does that relate to concentration?
Wed Feb 20, 2019 1:38 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: When does delta U equal zero?
Replies: 17
Views: 1844

### Re: When does delta U equal zero?

if the problem states that it is isothermal, q=0 and q=-w, since delta U = q+w, 0+0=0
Wed Feb 20, 2019 1:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Is there a significance with 298 degrees Kelvin?
Replies: 5
Views: 1783

### Re: Is there a significance with 298 degrees Kelvin?

Yes, 298 Degrees Kelvin is the standard for ideal gas.
Wed Feb 20, 2019 1:35 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: equations for q
Replies: 9
Views: 316

### Re: equations for q

if its just the C(delta) T, you are already included the amount of moles, instead of adding it in the beginning.(aka when you only have one mole)
Wed Feb 20, 2019 1:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Endothermic and Exothermic Graphs
Replies: 3
Views: 253

### Re: Endothermic and Exothermic Graphs

But keep in mind that delta H has a lot to do with this. and when measuring delta H you would measure from the beginning to the end state. (even if it does a big loop up, its just beginning and end result)
Wed Feb 20, 2019 1:32 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Most stable form?
Replies: 4
Views: 199

### Re: Most stable form?

What are the main things you would look for to determine its in the most stable form?
Wed Feb 20, 2019 1:30 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Using R
Replies: 10
Views: 341

### Re: Using R

You usually use R=8.314 , but the other values for R are given on the equation sheet.
Wed Feb 20, 2019 1:29 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Cp vs Cv
Replies: 7
Views: 513

### Re: Cp vs Cv

There are some times that they give you the C or heat capacity and you would just multiply this C by the number of moles.
Wed Feb 20, 2019 1:27 pm
Forum: Phase Changes & Related Calculations
Topic: Isothermal
Replies: 9
Views: 484

### Re: Isothermal

for the most part it should state that it is isothermal or that the temperature is constant.
Tue Feb 19, 2019 9:17 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work done vs work on system
Replies: 18
Views: 1381

### Re: Work done vs work on system

Think about it in terms of yourself.
if you're doing a workout, you lose energy.
But if someone else is doing it, you're positive energy.
Tue Feb 19, 2019 9:14 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Final exam
Replies: 8
Views: 406

### Re: Final exam

He will also give a ton of review sessions for the final in week 10 .
Tue Feb 19, 2019 9:14 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: R constants
Replies: 21
Views: 714

### Re: R constants

The best way to determine this is just to look if you can cancel out all the units.
Tue Feb 19, 2019 9:13 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Assume Ideal Behavior
Replies: 3
Views: 372

### Re: Assume Ideal Behavior

This "assume ideal behavior" just means you can us PV=nRT equation
Tue Feb 19, 2019 9:10 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: constant C
Replies: 7
Views: 399

### Re: constant C

just C is the heat capacity. C subunit P, is the heat capacity at the constant pressure. C subunit V is the heat capacity at constant volume.
Tue Feb 19, 2019 9:08 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Replies: 35
Views: 1127

the tests themselves are not curve. but as long as you get 250 points out of 500 points in the whole quarter you get a C-
Fri Dec 07, 2018 11:39 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Ordering Polarizability and Polarizing Power
Replies: 4
Views: 629

### Re: Ordering Polarizability and Polarizing Power

you determine the order based on the amount of electrons and the size of the atom. for Anions you are looking for the one that is more negativity. and for the cations you are looking for the most positive.
Fri Dec 07, 2018 11:34 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 5
Views: 279

### Lone Pairs

Only the lone pairs on the central atom affect the shape right? not the lone pairs on the other ones?
Fri Dec 07, 2018 11:31 am
Forum: Hybridization
Topic: Sigma bonds
Replies: 9
Views: 341

### Re: Sigma bonds

marg44 wrote:For these sigma and pi bonds, is one bond stronger than the other? Or are they of equal strength?

Sigma bonds are stronger and pi bonds are weaker.
Fri Dec 07, 2018 11:26 am
Forum: Bond Lengths & Energies
Topic: Bond strength & resonance structures
Replies: 2
Views: 343

### Bond strength & resonance structures

Can someone explain the correlation between the bond strength and resonance structures?
Fri Dec 07, 2018 11:21 am
Forum: *Stereochemistry
Topic: What's a stereocenter?
Replies: 5
Views: 1171

### Re: What's a stereocenter?

if it is on the final, is it used as a concept question or something more than that?
Fri Dec 07, 2018 11:16 am
Forum: *Shrodinger Equation
Topic: Shrodinger Equation meaning
Replies: 1
Views: 307

### Shrodinger Equation meaning

Can someone re explain this concept briefly ? i know we are not doing calculations (just conceptual) right?
Fri Dec 07, 2018 11:13 am
Forum: Bond Lengths & Energies
Topic: intermolecular forces
Replies: 1
Views: 328

### intermolecular forces

How do you determine what inter molecular forces could be present in a molecule?
Fri Dec 07, 2018 11:10 am
Forum: Calculating the pH of Salt Solutions
Topic: pH on final
Replies: 5
Views: 917

### pH on final

what are some questions that could be asked on the final using pH?
Fri Dec 07, 2018 11:08 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong Acids [ENDORSED]
Replies: 1
Views: 134

### Strong Acids[ENDORSED]

Can someone name all the strong acids? I know that it's a short list.
Tue Nov 13, 2018 5:43 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 6
Views: 359

### Re: Resonance Structures

That makes so much more sense! thank you!
Tue Nov 13, 2018 5:39 pm
Forum: Hybridization
Topic: How to Determine
Replies: 12
Views: 504

### Re: How to Determine

Can someone give a concrete example that would help better visualize this? thanks
Tue Nov 13, 2018 5:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 5
Views: 288

### Re: Bond Angles

If you do draw them out, I would recommend explicitly writing the degrees somewhere just to be safe. This will also show your TA that you know what bond angle is actually there without having to actually draw out a 109.5 degrees vs a 120 degree angle.
Tue Nov 13, 2018 5:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Biological Activity
Replies: 3
Views: 168

### Re: Biological Activity

This isn't something we particularly have to know, but its just saying that the shape plays a role in how certain things function. Like a protein would work better folded in a certain way vs if it was just a chain of amino acids. The shape can either improve its ability or diminish it.
Tue Nov 13, 2018 5:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Homework Problem: SOCl2 bond angles
Replies: 1
Views: 183

### Re: Homework Problem: SOCl2 bond angles

It has to do with the fact that they are both bonds. (vs it being lone pairs) because all ends are bonds and there are no lone pairs. the repelling is equally distributed.
Tue Nov 13, 2018 5:16 pm
Forum: Octet Exceptions
Topic: List of octect exceptions
Replies: 6
Views: 292

### Re: List of octect exceptions

For these exceptions are we able to draw a Lewis structure for them? (if any)
Tue Nov 13, 2018 5:11 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 6
Views: 359

### Resonance Structures

Can someone please give a formal definition to what resonance structures are? and why we use them?
Tue Nov 13, 2018 5:09 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Stable Vs. Formal
Replies: 4
Views: 585

### Stable Vs. Formal

Is there a difference between the stable charge and the formal charge? if they are explain please and thank you.
Tue Nov 13, 2018 4:57 pm
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Shape and Boiling Point
Replies: 12
Views: 1544

### Re: Shape and Boiling Point

Does the distance between the bonds effect the boiling point? Would this cause the bond to be stronger or weaker? This distance between the bonds would have an effect on the boiling point or how easily the bonds are broken. This is how I think about it to determine whether it is a stronger bond or ...
Tue Nov 13, 2018 4:55 pm
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Shape and Boiling Point
Replies: 12
Views: 1544

### Re: Shape and Boiling Point

I think most of what he was referring to with boiling point and shape, was how if there is more surface area touching than the rod for example would be a harder bond to break, versus when you look at to circles only has a little piece touching there for it is an easier bond to break.
Sat Nov 10, 2018 6:38 pm
Forum: Ionic & Covalent Bonds
Topic: Dissociation Energy
Replies: 3
Views: 172

### Re: Dissociation Energy

Okay, if the negative is releasing or absorbing energy what does the positive indicate?
Sat Nov 10, 2018 6:36 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Shielding [ENDORSED]
Replies: 15
Views: 1000

### Re: Shielding[ENDORSED]

WHAT DOES THIS EVEN MEAN????? I don't even remember this being talked about.
Sat Nov 10, 2018 6:32 pm
Forum: Quantum Numbers and The H-Atom
Topic: Degeneracy
Replies: 8
Views: 675

### Re: Degeneracy

To find how many degenerate orbitals there are using Ml.
let's say L is 1.
so Ml is =-1,0,1
by that we count how many there are in Ml (3). so we have three degenerate orbitals for this atom.
Sat Nov 10, 2018 6:30 pm
Forum: Trends in The Periodic Table
Topic: Bond Lenghts
Replies: 7
Views: 518

### Re: Bond Lenghts

Lavelle explained a bit more on the lengths and strengths of the bonds in class on Wednesday. I would ask him if you still have any doubts.
Sat Nov 10, 2018 6:28 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: E- configuration
Replies: 3
Views: 218

### E- configuration

Hi, can someone write like exactly what order we are suppose to write the configuration? because i keep getting mixed answers on whether s or d goes first. thanks
Sat Nov 10, 2018 6:27 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg equation
Replies: 3
Views: 553

### Re: Rydberg equation

wait, how does a negative indicate a higher state? is it because electrons are negative and as you have more it becomes more negative?
Sat Nov 10, 2018 6:25 pm
Forum: *Shrodinger Equation
Topic: Shrodinger Equation
Replies: 4
Views: 491

### Re: Shrodinger Equation

So if this is the case, did this have to do with the question on Test 2 about the probability of finding an electron in the center of an atom?
Fri Oct 12, 2018 1:37 pm
Forum: Molarity, Solutions, Dilutions
Topic: Finding the volume of stock solution to dilute
Replies: 13
Views: 738

### Re: Finding the volume of stock solution to dilute

The standard one for this equation is Liters, but if asked otherwise, you should probably use liters for your volume.
Fri Oct 12, 2018 1:36 pm
Forum: Limiting Reactant Calculations
Topic: How to determine the limiting reactant???? [ENDORSED]
Replies: 8
Views: 1893

### Re: How to determine the limiting reactant????[ENDORSED]

How I understood this was once you fin the amount in grams, the one with the bigger amount of moles that is need for the reaction is the limiting reactant. this is because you need more of this reactant to complete the equation. M9 in the textbook wasn't too much if you wanted a better idea with sma...
Fri Oct 12, 2018 1:28 pm
Forum: Molarity, Solutions, Dilutions
Topic: E23 part b
Replies: 4
Views: 442

### Re: E23 part b

I also got confused here.

But as in the beginning it says you are looking the amount of moles and even though it says molecules you're looking for the amount of moles in that molecule they presented.
Sun Oct 07, 2018 5:19 pm
Forum: Limiting Reactant Calculations
Topic: Module 3 Question
Replies: 3
Views: 93

### Re: Module 3 Question

Lavelle said the only way this could happen was in a nuclear reaction, but that we didn't have to worry about this until later.

so it can only be the same as or less than.
Sun Oct 07, 2018 5:01 pm
Forum: SI Units, Unit Conversions
Replies: 11
Views: 624

would you use the inverse if you're going in the opposite direction?

can someone clarify what would it be for :
- atoms to moles
- moles to atoms

thank you
Sun Oct 07, 2018 4:42 pm
Forum: SI Units, Unit Conversions
Topic: Fundamental E3
Replies: 6
Views: 322

### Re: Fundamental E3

you would multiply the actually quantity of gallium you have (9), by the molar mass given 70g/mol. this total will be equal to the molar mass of astatine 210g/mol times the amount of astatine you have. The amount of astatine is unknown so put a variable and then solve for it.

9 x 70 = 210 x A