Search found 51 matches
- Sat Mar 17, 2018 9:10 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Writing Cell Diagrams
- Replies: 3
- Views: 580
Re: Writing Cell Diagrams
I think that we will be given a chart and then we combine some of them to form this single product reaction.
- Sat Mar 17, 2018 9:03 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Pre equilibrium
- Replies: 5
- Views: 842
Re: Pre equilibrium
Yes you can!
- Sat Mar 17, 2018 8:56 pm
- Forum: General Rate Laws
- Topic: Test #3 Q. 3
- Replies: 2
- Views: 645
Re: Test #3 Q. 3
I believe that you use divide concentration over time, but remember to balance the equation!
- Fri Mar 16, 2018 3:43 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Porous Disk
- Replies: 2
- Views: 273
Porous Disk
Hey for the concentration cells, is there just a porous disk because there are the same components for the reactant and product?
- Sun Mar 11, 2018 11:30 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Adsorption
- Replies: 3
- Views: 462
Adsorption
What exactly is adsorption, I see that it says when reactants sit on the surface of the catalyst, but what does this mean?
- Sun Mar 11, 2018 11:28 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Heterogeneous vs Homogeneous
- Replies: 1
- Views: 261
Heterogeneous vs Homogeneous
Can someone describe the difference between a heterogeneous and homogeneous catalyst?
- Sun Mar 11, 2018 11:02 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Multiplying Equilibrium Constants
- Replies: 1
- Views: 274
Multiplying Equilibrium Constants
Can someone explain to me why during multistep reactions, when we add them we multiply the constants?
- Sat Mar 03, 2018 1:51 pm
- Forum: Zero Order Reactions
- Topic: Zero Order Reactions [ENDORSED]
- Replies: 3
- Views: 439
Re: Zero Order Reactions [ENDORSED]
I was confused as to why it is a zero order if the substance is independent of k, and what exactly it means by independent.
- Sat Mar 03, 2018 1:38 pm
- Forum: General Rate Laws
- Topic: Half Life
- Replies: 3
- Views: 460
Half Life
Just generally, since each half life equation is different depending on which order it is in, are they essentially the same thing but based off of their respective rate laws?
- Sat Mar 03, 2018 1:18 pm
- Forum: First Order Reactions
- Topic: Directly Proportional [ENDORSED]
- Replies: 1
- Views: 277
Directly Proportional [ENDORSED]
Hi so in my discussion this week, we talked about how first order graph is directly proportional. I'm a little confused to how or why this is, so can someone explain to me why this is directly proportional, and what zeroth order and second order reactions would be?
- Tue Feb 20, 2018 1:04 am
- Forum: Balancing Redox Reactions
- Topic: oxidation states
- Replies: 4
- Views: 642
Re: oxidation states
You use the periodic table and count the number of electrons needed to gain or lose to be the same as the noble gases.
- Tue Feb 20, 2018 12:54 am
- Forum: Balancing Redox Reactions
- Topic: Balancing redox reactions
- Replies: 1
- Views: 261
Re: Balancing redox reactions
So I am not completely sure, but I think you have to get the half reactions and balance them, then multiply those by a factor that results in the same number of electrons in both half reactions. Then we add the half reactions and cancel out the electrons and that should give the balanced redox react...
- Tue Feb 20, 2018 12:46 am
- Forum: Balancing Redox Reactions
- Topic: Oxidation Agents
- Replies: 4
- Views: 665
Oxidation Agents
So are oxidation agents different from what is being oxidized? I'm confused as to what the terminology is referring to.
- Sun Feb 18, 2018 9:15 pm
- Forum: Balancing Redox Reactions
- Topic: Half reaction
- Replies: 2
- Views: 257
Half reaction
Is it only for half reactions that E stays the same when being balanced since it is an intensive property?
- Sun Feb 18, 2018 8:45 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Reactant and Product
- Replies: 1
- Views: 255
Reactant and Product
I know that the one with the lower concentration would be the product, and the one with the higher concentration would be the reactant, but can someone please explain why that is? I thought the product would have a high concentration?
- Sun Feb 18, 2018 8:37 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Q
- Replies: 7
- Views: 878
Q
Is Q essentially the same thing as K but when the equation is not in equilibrium?
- Sat Feb 10, 2018 3:16 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Work
- Replies: 6
- Views: 980
Re: Work
Good question. I don't think so since it is in a vacuum and there is no change in temperature.
- Sat Feb 10, 2018 3:09 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: finding heat capacity using q=cΔT
- Replies: 3
- Views: 1053
Re: finding heat capacity using q=cΔT
Since you are looking for the specific heat capacity, you wouldn't be solving for q, but for Ccal. Therefore, you would divide q by delta T. I am unsure of where the negative comes from though.
- Sat Feb 10, 2018 2:58 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Standard State
- Replies: 2
- Views: 324
Standard State
How does whether it is standard state or not affect the change in enthalpy or entropy? What is its significance?
- Sun Feb 04, 2018 10:47 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Exothermic and Spontaneous
- Replies: 4
- Views: 9956
Re: Exothermic and Spontaneous
I believe that you can have a spontaneous endothermic such as melting ice.
- Sun Feb 04, 2018 10:28 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Measuring delta G
- Replies: 4
- Views: 820
Re: Measuring delta G
Calculate deltaG by using standard enthalpy of formation and standard entropy values of R and P. So delta G =deltaH-Tdelta S.
- Sun Feb 04, 2018 9:53 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Favorability
- Replies: 4
- Views: 921
Favorability
So is it essentially if the value of delta S or delta H is positive then it is not favorable, but if it is negative, then it is favorable? Can someone please clarify this for me?
- Sun Jan 28, 2018 12:10 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: W as a maximum
- Replies: 3
- Views: 427
Re: W as a maximum
so in the situation that it is at equilibrium, is w reversible then? Is the reversible just the negative of the maximum?
- Sat Jan 27, 2018 11:04 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Relationship between entropy and volume in liquids
- Replies: 5
- Views: 623
Re: Relationship between entropy and volume in liquids
Yeah so the entropy of gas molecules are much larger than that of liquid and solid molecules. Would zero gravity make it seem more gas like? I feel like for water to be more gas like, there has to be some vaporization, but that would just be a phase change and that would affect the entropy.
- Sat Jan 27, 2018 10:54 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Distribution
- Replies: 3
- Views: 421
Distribution
Hi I am confused as to why the microstates of different distributions are important to calculating w. Does this relate to using log properties?
- Sat Jan 20, 2018 8:23 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Table of bond enthalpies
- Replies: 4
- Views: 625
Table of bond enthalpies
Can someone please explain to me why the table of bond enthalpies refers to the break in bonds for gases. Also, why do we need to add enthalpy of phase changes for liquids and solids?
- Sat Jan 20, 2018 8:18 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Molar heat capacities of an ideal gas
- Replies: 2
- Views: 326
Re: Molar heat capacities of an ideal gas
I think this has to do something with the fact that as the volume gets larger, there will be more work to push the air.
- Sat Jan 20, 2018 4:04 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard State [ENDORSED]
- Replies: 2
- Views: 182
Re: Standard State [ENDORSED]
I was also wondering about this. In class, I believe that Dr. Lavelle told us that the most common ones were C(s),N2(g),O2(g),F2(g),Cl2(g),Br2(l),and I2(s). Are these the only ones we would encounter in tests? If not, how do we determine whether it is in standard state or not?
- Wed Jan 10, 2018 4:40 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies
- Replies: 5
- Views: 496
Re: Bond Enthalpies
Yes! You just add the energy required with the energy released, but the released energy would have a negative value. So its the energy required minus energy released.
- Wed Jan 10, 2018 3:40 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Exothermic reaction in bond enthalpy example in lecture
- Replies: 5
- Views: 384
Re: Exothermic reaction in bond enthalpy example in lecture
When bonds are formed, energy gets released. This results in a negative enthalpy, deltaH. If it is negative, then it is exothermic.
- Wed Jan 10, 2018 3:33 pm
- Forum: Phase Changes & Related Calculations
- Topic: qp=deltaH
- Replies: 8
- Views: 1021
qp=deltaH
So I understand that qp is essentially delta h and that is enthalpy, but for notation, is there going to be any instances when we would use qp?
- Fri Dec 08, 2017 4:43 pm
- Forum: Conjugate Acids & Bases
- Topic: Oxoacids
- Replies: 5
- Views: 756
Re: Oxoacids
So this is what I have come to understand. Hypochlorous Acid is an example of an oxoacid; so the chlorine is an electron withdrawing atom making the oxygen more likely to lost the H+ to be more stable.
- Fri Dec 08, 2017 4:30 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 5% Rule
- Replies: 1
- Views: 256
Re: 5% Rule
The 5% rule basically states that if x is less than 5% of the initial, then you can approximate it to be the same thing.
- Fri Dec 08, 2017 4:22 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: 25 degrees C
- Replies: 2
- Views: 426
25 degrees C
So I know that most of the time these reactions will occur in a lab that is 25 degrees Celsius, but what would we do to compensate if it is not in 25 degrees? What would we need to change?
- Fri Dec 08, 2017 3:19 am
- Forum: Lewis Acids & Bases
- Topic: HF
- Replies: 4
- Views: 607
Re: HF
It is considered a weak acid because it has a short bond length between the fluorine and the hydrogen ion. This means there is more energy holding them together and less acidic.
- Fri Dec 08, 2017 3:15 am
- Forum: Amphoteric Compounds
- Topic: Determining Amphoteric Compounds
- Replies: 3
- Views: 745
Re: Determining Amphoteric Compounds
from my understanding, it is amphoteric if you can draw a diagonal on the periodic table from a nonmetal to a metal, or a metal to a nonmetal.
- Fri Dec 08, 2017 3:05 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acid Strength
- Replies: 5
- Views: 3055
Re: Acid Strength
Yeah so HCl should be more acidic because it has a larger radius, therefore increasing the bond length between Cl and the H ion. This decreases the energy that it has, which makes it more stable. The more stable, the more acidic.
- Fri Dec 08, 2017 2:58 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Negative pH
- Replies: 2
- Views: 390
Re: Negative pH
Depending on the molarity of the H ions, I believe it is possible to measure a negative pH, but it is not typically seen when determining acidity.
- Thu Dec 07, 2017 3:47 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: negligible rule [ENDORSED]
- Replies: 3
- Views: 4333
Re: negligible rule [ENDORSED]
if we are given an equilibrium constant on a question, is that a good indicator that we are calculating a weak base or acid and therefore eliminate the x?
- Thu Dec 07, 2017 3:37 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: alternate method
- Replies: 1
- Views: 186
alternate method
I heard that there was an alternate method so calculating pH and pOH instead of using the ICE tables where we find the square root of Ka or Kb multiplied by the concentration. Is this a valid method?
- Thu Dec 07, 2017 3:18 pm
- Forum: Lewis Acids & Bases
- Topic: strong or weak
- Replies: 3
- Views: 388
strong or weak
Hi, during the final, what are some easy tricks that we can use to determine whether the acid or base is strong or weak? Also, can someone explain why when ions get larger, it becomes more acidic?
- Tue Nov 28, 2017 5:27 pm
- Forum: Sigma & Pi Bonds
- Topic: bonds relating to the internuclear axis
- Replies: 1
- Views: 334
bonds relating to the internuclear axis
Can someone confirm my thought process about this? So sigma bonds have electron density with symmetry around the internuclear axis like a single stick which allows it to rotate, but pi bonds are an addition on the side of the internuclear axis which prevents rotation right? Is it due to the face tha...
- Tue Nov 28, 2017 5:16 pm
- Forum: Sigma & Pi Bonds
- Topic: When do Sigma and Pi bonds occur?
- Replies: 4
- Views: 732
Re: When do Sigma and Pi bonds occur?
Essentially, in a single bond, there is going to be a sigma bond. A double bond has a sigma bond and a pi bond. That pi bond prevents rotation. A triple bond has a sigma bond and two pi bonds. I dont believe that there can be two sigma bonds together.
- Tue Nov 28, 2017 1:16 pm
- Forum: Hybridization
- Topic: general hybridization
- Replies: 2
- Views: 297
general hybridization
Hi, Im really confused with hybridization right now. I understood it during lecture, but I am lost now. Can someone explain to me a simple way to find the hybrid orbitals. Is it just based of the electrons being shared, or all the electrons including lone pairs?
- Tue Nov 28, 2017 12:47 pm
- Forum: Hybridization
- Topic: 4.31
- Replies: 2
- Views: 465
Re: 4.31
What I do is I add up all of the exponents (sp=2, sp^2=3,etc.). The sum I relate to the molecular structures so 2 would be linear, 4 is tetrahedral, etc.
hope this kinda helps. i know its a bad explanation.
hope this kinda helps. i know its a bad explanation.
- Tue Nov 28, 2017 12:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Internuclear Axis
- Replies: 1
- Views: 294
Internuclear Axis
Hi, so i was reviewing my notes and I saw "internuclear axis". I was wondering what that was. Is it just the area where electrons are being shared? Can someone please clarify this for me? Thanks!
- Fri Oct 20, 2017 4:52 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Electrostatic potential energy [ENDORSED]
- Replies: 2
- Views: 287
Re: Electrostatic potential energy [ENDORSED]
I believe that the charges relate to the electrons in the atom. Since we were learning about multi-electron atoms, I think the distance is the distance between the electrons.
- Fri Oct 20, 2017 4:38 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation
- Replies: 7
- Views: 900
Re: Rydberg Equation
In the equations sheet the rydberg equation is -hR/n^2 but i know that people have been using a different formula. I was wondering how they had this new "derived" formula that contains frequency. Thanks!
- Fri Oct 13, 2017 4:59 pm
- Forum: Properties of Electrons
- Topic: Wave Properties of Electrons [ENDORSED]
- Replies: 4
- Views: 627
Wave Properties of Electrons [ENDORSED]
Can someone help me understand how electrons passing through crystals also show diffraction? And how does that prove that elections must have wave-like properties?
- Fri Oct 13, 2017 4:54 pm
- Forum: Properties of Light
- Topic: Balmer Vs. Lyman
- Replies: 15
- Views: 4211
Re: Balmer Vs. Lyman
How does one determine whether emission is in part of the balmer series or lyman series? I know that the visible region is associated with the balmer series and the ultraviolet region associates the lyman series, but how do we determine the energy value?
- Wed Oct 04, 2017 4:29 pm
- Forum: Limiting Reactant Calculations
- Topic: Extensive vs. Intensive properties
- Replies: 2
- Views: 760
Extensive vs. Intensive properties
Hi, so I was confused on the differences between extensive and intensive properties. I wrote down that it has something to do with size, but im still confused. Can someone help me please? Thanks! Also does anyone know good supplemental videos or lessons that can help me review high school chem, sinc...