Search found 67 matches
- Sun Mar 17, 2019 3:43 pm
- Forum: Balancing Redox Reactions
- Topic: Triprotic
- Replies: 7
- Views: 3721
Triprotic
Is a triprotic acid an acid with 3 hydrogens?
- Sun Mar 17, 2019 3:38 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Rate of consumption
- Replies: 3
- Views: 626
Rate of consumption
Is there a difference between rate or consumption of a reactant and the rate a product is formed?
- Sat Mar 16, 2019 6:01 pm
- Forum: Balancing Redox Reactions
- Topic: Emf
- Replies: 1
- Views: 396
Emf
Is emf E or Enot?
- Sun Mar 10, 2019 4:48 pm
- Forum: Van't Hoff Equation
- Topic: Equilibrium
- Replies: 6
- Views: 719
Re: Equilibrium
Van Hoff's can find a K value knowing two different temperature or it can find a temperature knowing two different K values.
- Sun Mar 10, 2019 4:44 pm
- Forum: First Order Reactions
- Topic: graph
- Replies: 3
- Views: 2304
Re: graph
It changes based on whether it is integers or in ln form.
- Sun Mar 10, 2019 4:39 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: 15.63 Units with ln?
- Replies: 1
- Views: 173
Re: 15.63 Units with ln?
Make sure to write units when calculating. That makes it a lot easier to tell which units it's supposed to be. Also if you're given the order you can know what units k is suppose to be in.
- Mon Mar 04, 2019 11:06 am
- Forum: Van't Hoff Equation
- Topic: K value- Temp
- Replies: 6
- Views: 984
Re: K value- Temp
If you remember temperature is the only thing that can change K.
- Mon Mar 04, 2019 11:05 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation
- Replies: 4
- Views: 391
Re: Nernst Equation
You are often times given information for E or Ecell.
- Mon Mar 04, 2019 11:03 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: van't hoff equation
- Replies: 6
- Views: 710
Re: van't hoff equation
you can find K. Then since you know either k2 or k1 you can just plug one into the other. K= K2/ K1
- Sun Feb 24, 2019 6:56 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Redox equations in Basic conditions
- Replies: 3
- Views: 313
Re: Balancing Redox equations in Basic conditions
You have to make everything is balanced. P4 is the reactant for both equations. After you've split the equations balance the O's then balance the H's and lastly balance the charges. In a basic solution, you add H2O and OH to balance the reactions. Then you add elections to whichever side has the lea...
- Sun Feb 24, 2019 9:17 am
- Forum: Balancing Redox Reactions
- Topic: 14.5b (6th ed)
- Replies: 1
- Views: 229
Re: 14.5b (6th ed)
Yes. Br2 is the reactant in both half reactions.
- Sun Feb 24, 2019 9:15 am
- Forum: Balancing Redox Reactions
- Topic: Standard Cell Potential
- Replies: 3
- Views: 390
Re: Standard Cell Potential
Also he might ask questions about the cathode and anode and the second method gives you a better understanding of what is going on.
- Sun Feb 24, 2019 9:11 am
- Forum: Balancing Redox Reactions
- Topic: 14.5d
- Replies: 2
- Views: 229
Re: 14.5d
I had trouble with this one too. With 6OH and 6H2O the equation is still not balanced that's why you need 12OH and 12 H2O.
- Sun Feb 17, 2019 5:57 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: calculating delta G
- Replies: 4
- Views: 426
Re: calculating delta G
What do you mean by "what kind you're doing"? I would think that it is always in kelvins.
- Sun Feb 17, 2019 5:55 pm
- Forum: Van't Hoff Equation
- Topic: Different Constants of Eqn
- Replies: 3
- Views: 372
Re: Different Constants of Eqn
Yes, T is constant. In general if there it is a delta change or a ratio of T there is a change in temperature, but if it is just T temperature is constant.
- Sun Feb 17, 2019 5:54 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibb's Free energy
- Replies: 4
- Views: 462
Re: Gibb's Free energy
Delta G is spontaneity. From what I understand is if delta G is spontaneous it is also endothermic and if delta G is negative it is not spontaneous and it is exothermic.
- Sun Feb 10, 2019 3:43 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Residual entropy
- Replies: 2
- Views: 316
Re: Residual entropy
Also what exactly is residual entropy?
- Sun Feb 10, 2019 3:39 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 3/2R and 5/2R
- Replies: 5
- Views: 630
Re: 3/2R and 5/2R
How do you know when to assume it is a monatomic gas?
- Sun Feb 10, 2019 3:37 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: delta H and q
- Replies: 1
- Views: 215
delta H and q
I'm very confused as to why the textbook inter changes between delta H and q. I thought they weren't the same thing, but for many solutions the textbook will substitute delta H for q. Can someone please explain to me why this is possible.
- Sun Feb 10, 2019 3:35 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 8.51 The enthalpy formation of trinitrotoluene
- Replies: 1
- Views: 537
Re: 8.51 The enthalpy formation of trinitrotoluene
Because there are 4 TNT and you want to find it for just 1 mole of TNT.
- Sun Feb 10, 2019 3:32 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Assumptions
- Replies: 2
- Views: 273
Assumptions
In the homework the textbook often assumes something is an ideal gas or the pressure is constant. How do we know when we can make assumptions like those?
- Sun Feb 03, 2019 9:05 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Units
- Replies: 7
- Views: 604
Units
Okay I feel really dumb for asking this but is J.C-1.mol-1 equal to J/C.mol or J/C/mol?
- Sun Feb 03, 2019 8:58 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: K vs. C in calculations
- Replies: 2
- Views: 266
Re: K vs. C in calculations
You need to always have the same units, but delta t is a change in final and initial and 1 C change is equivalent to 1 K change thats why you were able to calculate delta T in C because it is the same as in K.
- Sun Feb 03, 2019 8:52 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Clarification on Gibbs
- Replies: 2
- Views: 323
Re: Clarification on Gibbs
I don't think there is a part of the equation that accounts for attractive and repulsive forces on each other.
- Sat Jan 26, 2019 11:07 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess’s Law
- Replies: 2
- Views: 245
Re: Hess’s Law
Also you might have to switch some of the equations and make the products the reactants. If you do so make sure the multiply the enthalpy by -1 of the specific reaction.
- Sat Jan 26, 2019 11:06 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: heat capacity
- Replies: 7
- Views: 753
Re: heat capacity
Heat capacity just depends on the final and initial values that is why it is a state property.
- Wed Jan 23, 2019 10:33 pm
- Forum: Ideal Gases
- Topic: ICE Table Values
- Replies: 9
- Views: 1237
Re: ICE Table Values
The ice tables can be used with moles, concentration, pressure but you need to make sure you know what you're using so that you can convert correctly at the end.
- Mon Jan 21, 2019 9:35 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Calculating pH of a weak acid and its salt
- Replies: 4
- Views: 654
Re: Calculating pH of a weak acid and its salt
yes, there is just an initial concentration for the salt as well as the weak acid. But the steps are the same.
- Mon Jan 21, 2019 9:30 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Temperature for Equilibrium
- Replies: 4
- Views: 288
Re: Temperature for Equilibrium
It depends on the molecules. For instance 25 degrees C is the equilibrium temperature for water.
- Mon Jan 21, 2019 9:28 am
- Forum: Ideal Gases
- Topic: 5% rule
- Replies: 12
- Views: 3396
Re: 5% rule
you can still do the 5% rule he sort of did an example like this in lecture on Wednesday I believe.
- Mon Jan 21, 2019 9:25 am
- Forum: Ideal Gases
- Topic: ICE table
- Replies: 11
- Views: 1261
Re: ICE table
You can use it for both you just need to pay attention to what you are using when coming up with a final answer.
- Sun Jan 13, 2019 8:39 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Determining Which side is favored
- Replies: 5
- Views: 662
Re: Determining Which side is favored
yes since there is more reactant more product will be formed.
- Sun Jan 13, 2019 8:38 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K value
- Replies: 2
- Views: 71
Re: K value
K value doesn't determine if its spontaneous or not.
- Sun Jan 13, 2019 8:34 pm
- Forum: Ideal Gases
- Topic: ICE Table
- Replies: 4
- Views: 414
Re: ICE Table
how do you know when your suppose to subtract just x or subtract something like 2x?
- Sun Dec 09, 2018 7:54 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final Grade View
- Replies: 7
- Views: 906
Re: Final Grade View
It depends on your TA. If you want to get you test back before we go to break email your TA.
- Sun Dec 09, 2018 7:52 pm
- Forum: Lewis Acids & Bases
- Topic: Stronger Acid
- Replies: 1
- Views: 414
Re: Stronger Acid
Cl is a large atom than F so that means the the bond length of HCl is longer than the bond length of HF so HCl has a weak bond. Since the bond is weaker HCl is more likely to donate the H+ making it a stronger acid.
- Sun Dec 09, 2018 7:50 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: H-atom
- Replies: 1
- Views: 1823
Re: H-atom
yes.
- Sun Dec 02, 2018 10:11 am
- Forum: Naming
- Topic: endings in naming
- Replies: 3
- Views: 166
Re: endings in naming
If a molecule or element is outside of the brackets like Cl3 then it would just be chloride not tricholoro.
- Sun Dec 02, 2018 10:07 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Negative pH?
- Replies: 5
- Views: 521
Re: Negative pH?
A negative pH can be calculated, I'm just not sure why. But it is possible.
- Sun Dec 02, 2018 10:03 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Model
- Replies: 5
- Views: 551
Re: VSEPR Model
When he says use the VSPER Model his is saying to refer to it when answering the question. So you should take in consideration the formula, shape (lone pairs), and bond angles.
- Mon Nov 26, 2018 12:00 am
- Forum: Sigma & Pi Bonds
- Topic: Hybridization and Electron Configurations
- Replies: 3
- Views: 438
Re: Hybridization and Electron Configurations
I don't think so.
- Sun Nov 25, 2018 11:59 pm
- Forum: Bond Lengths & Energies
- Topic: How to Measure Bond Lengths
- Replies: 4
- Views: 519
Re: How to Measure Bond Lengths
You do need to know that single bonds are the longest, then it's doubles bonds and triple bands are the shortest out of the three.
- Sun Nov 25, 2018 11:57 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Naming Shapes
- Replies: 5
- Views: 489
Re: Naming Shapes
I've just memorized the shapes it is the quickest way to name molecules which is really important for the test since you don't want to run out of time.
- Sun Nov 18, 2018 8:36 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape
- Replies: 4
- Views: 375
Re: Molecular Shape
the molecular shape helps more because it shows the actual arrangement of the atoms where as the geometry just says how many bonds or regions of bonds around the central atom. The geometry doesn't include lone pairs.
- Thu Nov 15, 2018 3:45 pm
- Forum: Lewis Structures
- Topic: Maximum amount of bonds
- Replies: 5
- Views: 604
Re: Maximum amount of bonds
Usually the central atom doesn't have a high formal charge. It depends what the charge is of the full compound. If the compound is neutral then the central atom should have a formal charge of 0 or a formal charge that cancels out the formal charge of the other atoms.
- Thu Nov 15, 2018 3:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Coordination Numbers
- Replies: 1
- Views: 154
Re: Coordination Numbers
We haven't gone over this in lecture as far as I know. Dr. Lavelle will most likely answer you question in the following lectures.
- Thu Nov 15, 2018 3:37 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Planar vs Pyramidal
- Replies: 3
- Views: 1418
Re: Planar vs Pyramidal
If the central atom has three bonds and no lone pairs then it will be trigonal planar it doesn't matter if the elements are different.
- Sun Nov 11, 2018 12:40 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm [ENDORSED]
- Replies: 14
- Views: 1496
Re: Midterm [ENDORSED]
He doesn't post grades on CCLE just on my UCLA, but he hasn't updated grades as far as I know.
- Sun Nov 11, 2018 12:38 pm
- Forum: Bond Lengths & Energies
- Topic: VSEPR Model for Water
- Replies: 3
- Views: 376
Re: VSEPR Model for Water
Because CO2 has double bonds and H2O doesn't.
- Sat Nov 10, 2018 10:22 pm
- Forum: Ionic & Covalent Bonds
- Topic: delta positive delta negative
- Replies: 15
- Views: 2242
delta positive delta negative
How do you know which end of a molecule is delta positive or delta negative?
- Sun Nov 04, 2018 7:55 pm
- Forum: Electronegativity
- Topic: How much can you round down for empirical formulas?
- Replies: 2
- Views: 1000
Re: How much can you round down for empirical formulas?
My PLF said that for example if you got the value 1.09 you can't assume 1 but anything lower than 1.09 you can assume one. So in general if it is less than .09 away from a whole number you can still round to that whole number.
- Sun Nov 04, 2018 7:52 pm
- Forum: Octet Exceptions
- Topic: Formal charge
- Replies: 7
- Views: 887
Re: Formal charge
You should always check the formula charge when you're drawing a lewis structure no matter way. This way you can make sure that the lewis structure you drew is the best one.
- Sun Nov 04, 2018 7:47 pm
- Forum: Resonance Structures
- Topic: Tricks for Resonance Structures
- Replies: 5
- Views: 873
Re: Tricks for Resonance Structures
I'm pretty sure we won't need to know how many resonance structures we need to draw, the problems will tell us how many resonance we need to draw.
- Sun Nov 04, 2018 7:43 pm
- Forum: Ionic & Covalent Bonds
- Topic: Midterm questions
- Replies: 5
- Views: 425
Re: Midterm questions
We only need to know the things Dr. Lavelle covered up until wednesday's lecture.
- Sun Oct 28, 2018 4:03 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: CH 3 problem 5 [ENDORSED]
- Replies: 1
- Views: 143
CH 3 problem 5 [ENDORSED]
How do I do 5a because I know that Copper can have exceptions. Give the ground-state electron configuration expected for
each of the following ions: Cu^+
each of the following ions: Cu^+
- Sun Oct 28, 2018 3:52 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3004396
Re: Post All Chemistry Jokes Here
Want to hear a joke about sodium, bromine, and oxygen?
NaBrO
NaBrO
- Sun Oct 28, 2018 3:31 pm
- Forum: Ionic & Covalent Bonds
- Topic: Friday 10/26/18 lecture
- Replies: 4
- Views: 541
Re: Friday 10/26/18 lecture
ionic and covalent bonds
- Sat Oct 20, 2018 11:26 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Test Two
- Replies: 2
- Views: 261
Test Two
Does anyone know if we're suppose to know about electron configuration for the test? He said we would only need to know the stuff he lecture about up until friday's lecture, but he didn't really go over electron configuration and that is in outline 2. I don't know if I should study it for the test.
- Sat Oct 20, 2018 11:21 am
- Forum: Einstein Equation
- Topic: wave vs particle behavior equations
- Replies: 2
- Views: 318
Re: wave vs particle behavior equations
Also the DeBroglie Equations is for objects with mass.
- Sat Oct 20, 2018 11:18 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Indeterminacy Equation as an inequality
- Replies: 1
- Views: 103
Re: Heisenberg Indeterminacy Equation as an inequality
The symbol doesn't need to be there because you are just finding the missing value. The symbol is just there for the purpose of finding the missing value because we are uncertain of what exactly the number is that's why there can't be a = symbol.
- Sat Oct 20, 2018 11:13 am
- Forum: DeBroglie Equation
- Topic: Application to Classical Objects
- Replies: 2
- Views: 235
Re: Application to Classical Objects
Everything has a wavelength (even we do). The DeBroglie wavelength is for things with mass such as a baseball or a human. The wavelength in the equation for speed of light is the wavelength for photons. These two wavelength are not the same thing. One is for objects with mass while the other one is ...
- Sat Oct 13, 2018 7:14 pm
- Forum: Photoelectric Effect
- Topic: Problem 33 Chapter 1
- Replies: 1
- Views: 142
Problem 33 Chapter 1
How do you know which equations to use for number 33? I started of my using E=hv and got a very small number so I decided to look in the solutions manual and it showed that I should be using the De Broglie equation. When do you know you should use that equation?
- Sat Oct 13, 2018 7:10 pm
- Forum: Photoelectric Effect
- Topic: 1B.9: Trouble with exponents and units
- Replies: 3
- Views: 971
Re: 1B.9: Trouble with exponents and units
It could most likely be that you're plugging in things wrong into your calculator or you aren't using parenthesis. Because I multiplied 2 by 32 to cancel out the seconds and got 64 J. You the use the E= hc/wavelength equation and plug in what is given. You should get 4.7x10^-19 J photons^-1. After t...
- Sat Oct 13, 2018 6:56 pm
- Forum: Properties of Light
- Topic: Homework Question 1A.3
- Replies: 4
- Views: 430
Re: Homework Question 1A.3
The answer is actually c. The extent of change is referring to the slope of the wave so when the frequency decreases the wave gets wider which means that the extent of change is decreases.
- Sat Oct 06, 2018 10:45 am
- Forum: Balancing Chemical Reactions
- Topic: H3, coefficients
- Replies: 7
- Views: 660
Re: H3, coefficients
It depends what kind of formula it was looking for. If it's molecular you shouldn't simplify, but if it's empirical then you should simplify.
- Sat Oct 06, 2018 10:37 am
- Forum: General Science Questions
- Topic: Rounding up with Sig Figs
- Replies: 3
- Views: 353
Re: Rounding up with Sig Figs
Rounding up would make the most sense. Rounding down would change the final answer from what it really is.
- Sat Oct 06, 2018 10:30 am
- Forum: Student Social/Study Group
- Topic: HW Schedule?
- Replies: 7
- Views: 910
Re: HW Schedule?
Does anyone know if homework for outline 2 is due on the day we have the test about the high school review?