## 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: 340

### 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: 469

### 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: 430

### 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: 175

### 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
Replies: 3
Views: 214

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: 105

### 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: 144

### 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: 255

### 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: 230

### 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: 158

### 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: 278

### 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: 140

### 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: 239

### 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: 119

### 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: 112

### 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: 433

### 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: 623

### 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: 508

### 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: 163

### 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: 4708

### 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: 304

### 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: 301

### 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: 233

### 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: 277

### 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: 219

### 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: 330

### 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: 219

### 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: 106

### 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: 241

### 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: 263

### 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: 549

### 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: 506

### 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: 179

### 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: 241

### 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: 347

### 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: 485

### 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: 587

### 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: 215

### 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: 3730

### 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: 153

### 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: 291

### 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: 211

### 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: 466

### 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: 217

### 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: 265

### 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.
Tue Nov 28, 2017 12:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Internuclear Axis
Replies: 1
Views: 212

### 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: 190

### 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: 561

### 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: 418

### 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: 12
Views: 1739

### 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: 413

### 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...