Search found 169 matches

by AtreyiMitra2L
Sat Mar 17, 2018 10:51 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrodes
Replies: 3
Views: 184

Re: Electrodes

When there is no solid metal in a reaction, add Pt(s).
by AtreyiMitra2L
Sat Mar 17, 2018 10:49 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Adiabatic vs Isothermal
Replies: 5
Views: 320

Re: Adiabatic vs Isothermal

Adiabatic is when there is no transfer of heat. Iso thermal is when the change in internal energy is 0.
by AtreyiMitra2L
Sat Mar 17, 2018 10:46 pm
Forum: *Ketones
Topic: Keytone and Aldeyhdes
Replies: 3
Views: 528

Re: Keytone and Aldeyhdes

Aldehyde is on the end and ketone is in the middle.
by AtreyiMitra2L
Sat Mar 17, 2018 2:52 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram: Porous Disk and Salt Bridge
Replies: 5
Views: 191

Re: Cell Diagram: Porous Disk and Salt Bridge

For the salt bridge, we use the double line and for the porous disk we use a single line.
by AtreyiMitra2L
Sun Mar 11, 2018 11:14 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL
Replies: 9
Views: 555

Re: FINAL

Everything but 15.9.
by AtreyiMitra2L
Sun Mar 11, 2018 11:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 6
Views: 219

Re: Cell Diagrams

In general, have the anode go first and the cathode go next. The inert metals should go on the ends. For those in the middle, don't worry too much about the order as Dr. Lavelle has said that it is not that important.
by AtreyiMitra2L
Sun Mar 11, 2018 11:12 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Molar Entropy
Replies: 9
Views: 423

Re: Molar Entropy

Generally, the heavier the substance, the higher the molar entropy. This occurs because the energy levels are closer together, which means there are more possible orientations the substance can acquire. Therefore, it will have a higher molar entropy.
by AtreyiMitra2L
Sun Mar 11, 2018 11:10 pm
Forum: Balancing Redox Reactions
Topic: redox
Replies: 6
Views: 222

Re: redox

I basically look at what reactant is being oxidized and name that the reducing agent. Then I look atwhat reactant is being reduced and name that the oxidizing agent.
by AtreyiMitra2L
Sun Mar 11, 2018 11:09 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isothermal Processes
Replies: 2
Views: 218

Re: Isothermal Processes

furthermore, it is important to note that for isothermal, reversible processes, the change in internal energy is 0 when they are ideal gases. Because they are ideal gases, there is no exhange in energy during the collisions.
by AtreyiMitra2L
Sun Mar 11, 2018 11:08 pm
Forum: *Enzyme Kinetics
Topic: Enzyme
Replies: 5
Views: 366

Re: Enzyme

Enzymes, by defintion, are catalysts. Therefore, they work by speeding up the reaction and not by slowing down.
by AtreyiMitra2L
Sun Mar 11, 2018 11:07 pm
Forum: Calculating Work of Expansion
Topic: Midterm 4a
Replies: 5
Views: 310

Re: Midterm 4a

Because we know its constant external pressure, we automatically know that its undergoing an irreversible expansion.
by AtreyiMitra2L
Sun Mar 11, 2018 11:06 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Intermediates
Replies: 6
Views: 176

Re: Intermediates

Yes. An intermediate is just a substance that is produced and used in the reaction in a manner that it isnt shown in the final reaction. Because this occurs, it will be an intermediate even if it is isnt shown in step 3
by AtreyiMitra2L
Sun Mar 11, 2018 11:05 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Intermediates
Replies: 2
Views: 126

Re: Intermediates

We can determine the intermediates of the reaction by looking at which cancel out throughout the reaction. By doing this, we can also figure out the number.
by AtreyiMitra2L
Sat Mar 10, 2018 1:39 pm
Forum: Student Social/Study Group
Topic: Chem 14BL Exchange
Replies: 1
Views: 249

Chem 14BL Exchange

Hi! Im posting here about this because Im desperate LOL. I am currently enrolled next quarter in chem 14BL with casey in lab 1j (Thursday 6:30 pm - 9:20 pm). I am looking to exchange with anyone from casey or the other professor for a different time lab with chem 14BL. Please comment below if intere...
by AtreyiMitra2L
Mon Mar 05, 2018 12:07 am
Forum: General Rate Laws
Topic: general rate laws
Replies: 3
Views: 121

Re: general rate laws

Yes this is the general rule
by AtreyiMitra2L
Mon Mar 05, 2018 12:06 am
Forum: General Rate Laws
Topic: zero order in rate laws
Replies: 8
Views: 232

Re: zero order in rate laws

We can include them but its . not needed.
by AtreyiMitra2L
Mon Mar 05, 2018 12:06 am
Forum: Zero Order Reactions
Topic: Identifying zero order
Replies: 6
Views: 204

Re: Identifying zero order

You need the table to identify 0 order reactions
by AtreyiMitra2L
Sun Feb 25, 2018 11:30 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Cell Potential
Replies: 4
Views: 140

Re: Cell Potential

It just the standard because we can only calculate the change rather than the actual value
by AtreyiMitra2L
Sun Feb 25, 2018 11:30 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: how to write a cell diagram [ENDORSED]
Replies: 6
Views: 403

Re: how to write a cell diagram [ENDORSED]

Have the anode then cathode. The inert metals should be on the outside. besides that dont stress
by AtreyiMitra2L
Mon Feb 19, 2018 3:44 pm
Forum: Balancing Redox Reactions
Topic: Balancing H
Replies: 2
Views: 112

Re: Balancing H

For basic solutions, to balance O's we use water. Then to balance H's, we use OH's and H2Os on both side.
by AtreyiMitra2L
Mon Feb 19, 2018 3:41 pm
Forum: Balancing Redox Reactions
Topic: Half reaction of O3 to O2
Replies: 1
Views: 104

Re: Half reaction of O3 to O2

On the right, you see two hyrdroxide ions. This means that there is -2 on that side. To balance the equation, you need negative 2 on the other side. This is why we have 2 electrons.
by AtreyiMitra2L
Mon Feb 19, 2018 3:40 pm
Forum: Balancing Redox Reactions
Topic: Test 2
Replies: 3
Views: 137

Re: Test 2

We will have to know how to do both. The list of constants and equations is on his website.
by AtreyiMitra2L
Sun Feb 18, 2018 6:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Arranging in order of increasing strength
Replies: 3
Views: 2500

Re: Arranging in order of increasing strength

but even then, when you look them up there seem to be several possible values. How do you know which one to use.
by AtreyiMitra2L
Sun Feb 18, 2018 5:54 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram
Replies: 2
Views: 109

Re: Cell diagram

In question 14.21a, we have mercury. Mercury, while a metal, is liquid at room temp. In the answer key, we dont have a inert metal there. Do we use inert metallic components for all metals?
by AtreyiMitra2L
Sun Feb 18, 2018 5:38 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: reversible system
Replies: 9
Views: 388

Re: reversible system

Delta s total will only be 0.
by AtreyiMitra2L
Sun Feb 18, 2018 5:38 pm
Forum: Balancing Redox Reactions
Topic: agents
Replies: 3
Views: 124

Re: agents

I just think the oxidation agent is the substance being reduced on the reactants side and the reducing agent is the substance being oxidized on the reactants side.
by AtreyiMitra2L
Sun Feb 18, 2018 5:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell reactions
Replies: 1
Views: 67

Re: Cell reactions

You have to split it up into half reactions. From there, try to see whether oxidation or reduction is occuring. If oxidation is occuring, we have the anode. If reduction is occuring, we have the cathode.
by AtreyiMitra2L
Tue Feb 13, 2018 9:47 am
Forum: Administrative Questions and Class Announcements
Topic: Practice Midterm Winter 2018
Replies: 10
Views: 2039

Re: Practice Midterm Winter 2018

How did we calculate heat and work in number 4 on the midterm?
by AtreyiMitra2L
Mon Feb 12, 2018 8:38 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: entropy sign
Replies: 5
Views: 176

Re: entropy sign

If there is net increase of gaseous moles --> increase in entropy. If there is a net decrease --> decrease in entropy. If appearence of aqueous, net increase. if we see an increase in molecular complexity with the products --> net increase.
by AtreyiMitra2L
Mon Feb 12, 2018 8:36 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Gas Constant, R
Replies: 6
Views: 221

Re: Gas Constant, R

We often use 0.0821 when calulating with PV = nrT. For the others, it is possible I suppose.
by AtreyiMitra2L
Mon Feb 12, 2018 8:35 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Units of Delta H
Replies: 2
Views: 150

Re: Units of Delta H

They are relatively interchangeable when there is only one mole. But if two mole of the product is formed, if you have it as kj per mole, you would need to multiply your value by 2.
by AtreyiMitra2L
Mon Feb 12, 2018 8:34 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: delta S(system) vs delta S(surroundings)
Replies: 4
Views: 767

Re: delta S(system) vs delta S(surroundings)

This can only occur in isothermal, reversible reactions. It would not be considered a violation of the second law of thermodynamics (law that says the entropy is always increasing) because these never actually occur in nature.
by AtreyiMitra2L
Mon Feb 12, 2018 8:33 pm
Forum: Calculating Work of Expansion
Topic: Reversible, isothermal reactions
Replies: 1
Views: 91

Reversible, isothermal reactions

Do all reversible reactions occur isothermally?
by AtreyiMitra2L
Sun Feb 11, 2018 11:54 pm
Forum: Calculating Work of Expansion
Topic: different ways to calculate w
Replies: 4
Views: 163

Re: different ways to calculate w

We use the former with constant pressure and the latter when its not constant pressure. The first is irreversible expansion and the latter is irreversible, isothermal expansion.
by AtreyiMitra2L
Sun Feb 11, 2018 11:53 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: Third Law's W
Replies: 3
Views: 141

Re: Third Law's W

W is degeneracy. it doesnt have units. You calculate it by doing the number of orientations ^ (num of molecules)
by AtreyiMitra2L
Fri Feb 09, 2018 2:12 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Question 9.21
Replies: 4
Views: 169

Re: Question 9.21

If it is in the same direction, you know there is only one possible orienation. Therefore, regardless of how many molecules, the entropy using the boltzman equation will still be found to be 0. This occurs because the W in this equation is found by (# of possible orientations) ^ (# of molecules). In...
by AtreyiMitra2L
Fri Feb 09, 2018 2:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Lecture Slides
Replies: 6
Views: 282

Re: Lecture Slides

The lecture slides are in the course reader than he no longer sells. Getting this would be your best bet.
by AtreyiMitra2L
Fri Feb 09, 2018 2:09 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: delta G=0
Replies: 6
Views: 200

Re: delta G=0

When delta g is 0, it just means that it is at equilibrium. It is not enough to assume the other two quantities to alse be at 0.
by AtreyiMitra2L
Fri Feb 09, 2018 2:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode and cathode
Replies: 9
Views: 240

Re: Anode and cathode

At the anode, oxidation is occuring. At the cathode, reduction is occuring. If you know these concepts and look at the diagram enough, you will be able to distinguish the two
by AtreyiMitra2L
Fri Feb 09, 2018 2:07 pm
Forum: Phase Changes & Related Calculations
Topic: Units for Internal Energy
Replies: 5
Views: 168

Re: Units for Internal Energy

I think its preferable to use KJ but you could use either one
by AtreyiMitra2L
Fri Feb 09, 2018 2:06 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Calculating the change in entropy with constant pressure
Replies: 2
Views: 110

Calculating the change in entropy with constant pressure

When the question says the reaction is occuring at constant pressure, can we use C instead of C (p,m) in our equation (change in S = nC(p,m)ln(T2/T1)? Thanks!
by AtreyiMitra2L
Thu Feb 01, 2018 11:15 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Mass and molar entropy
Replies: 3
Views: 147

Mass and molar entropy

Why do substances with larger masses have larger molar entropies?
by AtreyiMitra2L
Thu Feb 01, 2018 11:13 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Molar Entropy
Replies: 2
Views: 135

Re: Molar Entropy

The molar entropy is basically the entropy per mole of a substance. If you want to find the molar entropy, you need to know how many possible positions the molecules has as in number 25. Then, you have an exponent with Avagadoros number. You plug all this in the boltzman equation and you should be g...
by AtreyiMitra2L
Thu Feb 01, 2018 11:10 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: The value of Cp
Replies: 8
Views: 300

Re: The value of Cp

On the test, you will be given the table of values that will help you solve for cP
by AtreyiMitra2L
Thu Jan 25, 2018 8:07 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Combustion Equations [ENDORSED]
Replies: 4
Views: 190

Re: Combustion Equations [ENDORSED]

The book says that water in the liquid form will be formed only with organic compounds. When it is not an organic compund, then gas will be formed.
by AtreyiMitra2L
Thu Jan 25, 2018 8:04 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Reaction enthalpy involving H-H
Replies: 2
Views: 139

Re: Reaction enthalpy involving H-H

Bond enthalpy is the amount of energy to break one mole of the substance. On the other hand, enthalpy of formation is the amount of energy required to make the substance by substances in their standard states (the state at which they will be found at 1 atm). H2 at one atm is in gas. Therefore, becau...
by AtreyiMitra2L
Thu Jan 25, 2018 8:01 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.49
Replies: 2
Views: 125

Re: 8.49

To look for the net production of gas, you simply subtract the moles of the gas on the product side by the moles of gas from the reactants side. The one mole of OF2 is just refering for the final answer to be in per mole.
by AtreyiMitra2L
Thu Jan 25, 2018 8:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: change in enthalpy
Replies: 2
Views: 107

Re: change in enthalpy

I believe it is deltaU = deltaH - delta(n)RT. This goes off of the concept that delta u is equal to q + w. (AKA the second one). Work is the second one. This occurs because of the idea of what the work is being done on or by what. In expansion, the work is being done ON the surroundings BY the syste...
by AtreyiMitra2L
Thu Jan 25, 2018 11:34 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat and temp difference
Replies: 2
Views: 125

Heat and temp difference

Why is it that in isothermal, reversible expansion heat can be done if heat is defined as the transfer of energy due to a temperature difference? I understand that the change in internal energy must be 0 for ideal gases so heat must be involved but I dont understand it past this. Thanks!
by AtreyiMitra2L
Tue Jan 23, 2018 5:36 pm
Forum: Calculating Work of Expansion
Topic: Natural Log
Replies: 1
Views: 68

Re: Natural Log

Well, usually for irreverisible, work = -Pex * (delta V). I am not sure where your equation came from. I believe in this class for reversible, isothermal expansion, all you have to worry about is the one with natural log.
by AtreyiMitra2L
Tue Jan 23, 2018 5:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess' Law fractions
Replies: 3
Views: 341

Re: Hess' Law fractions

In hess's law, we are calculating the overall enthalpy change. Because enthalpy is a state function, we know it isnt pathway dependent. Therefore, it doesn't matter which way it got there. If you have fractions, as long as you changed enthalpy along with it its fine :)
by AtreyiMitra2L
Tue Jan 23, 2018 5:33 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Monatomic Gas
Replies: 5
Views: 202

Re: Monatomic Gas

R is related to the gas constant or 8.3145 J/ (K x mol). It will just be a constant.
by AtreyiMitra2L
Tue Jan 23, 2018 5:31 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: R -> P vs. P -> R
Replies: 3
Views: 124

Re: R -> P vs. P -> R

For bond enthalpies, I believe you got the order wrong. It should be reactants - products. This idea is built on the idea that to break bonds in the reactants. To build the bonds in the products, there is a release of energy. Therefore, there is reatants - products.
by AtreyiMitra2L
Tue Jan 23, 2018 5:28 pm
Forum: Phase Changes & Related Calculations
Topic: Combustion of liquids
Replies: 4
Views: 181

Combustion of liquids

Hello! When a liquid combusts, will liquid water be produced and not gaseous water? Does this always happen? I am asking this specifically in reference to num 93 in which the combustion of c6h6 seems to produces liquid water. Thanks!
by AtreyiMitra2L
Mon Jan 15, 2018 10:13 pm
Forum: Phase Changes & Related Calculations
Topic: Types of Systems
Replies: 10
Views: 377

Re: Types of Systems

In a closed system, there is an exchange of energy but not matter. The example in the book given is a refrigerator coil. This is a closed system because the coil cools the refrigerator through the transfer of energy. There is no exchange of the fluid, however, In contrast, in an isolated system, the...
by AtreyiMitra2L
Mon Jan 15, 2018 10:11 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 8.77
Replies: 2
Views: 98

Re: 8.77

This concept goes back to 14A. In reasonance, delocalization occurs. Because the electrons are spread over a wider area, the resulting substance is more stable because there are fewer electron electron repulsions.
by AtreyiMitra2L
Mon Jan 15, 2018 10:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: rxn enthalpy vs. rxn internal energy
Replies: 1
Views: 70

Re: rxn enthalpy vs. rxn internal energy

I think because we are supposed to be looking at it in terms of the absolute value. In chemistry, we always take the system's perspective. In physics, however, we usually take the surrounding's perspective. Because of this discepancy, we look at it in terms of absolute value. Please don't hesitate t...
by AtreyiMitra2L
Mon Jan 15, 2018 10:07 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess Law
Replies: 4
Views: 167

Re: Hess Law

Yes you can! These properties are all possible because enthalpy is a state function. In other words, it doesnt matter how it got there. The end result will still be the same.
by AtreyiMitra2L
Mon Jan 15, 2018 10:06 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework 8.29
Replies: 5
Views: 178

Re: Homework 8.29

If you think about it, the more atoms there are, the more heat is required to raise the substance by 1 degree celsius. Therefore, because NO2 has 3 atoms rather than only 2, it takes more heat because there are more atoms that can absorb the heat.
by AtreyiMitra2L
Mon Jan 15, 2018 10:04 pm
Forum: Phase Changes & Related Calculations
Topic: Heat and Enthalpy
Replies: 3
Views: 132

Heat and Enthalpy

Why is it that heat at constant pressure (enthalpy) is considered a state function but not heat? Thanks!
by AtreyiMitra2L
Fri Jan 12, 2018 11:23 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Most Stable Forms
Replies: 4
Views: 194

Re: Most Stable Forms

For it to be the most stable form, it must be the one that is most pure. Some of them you just have to memorize. But there are some that you can figure out. All noble gases are most stable in the element phase as a gas. All diatomic gases (such as N2, O2, Cl2, F2, H2, etc.) are the most stable in th...
by AtreyiMitra2L
Fri Jan 12, 2018 11:15 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Example 8.13
Replies: 2
Views: 119

Re: Example 8.13

I have two questions regarding this question. 1. How do you know which atoms you need to break/form during this reaction? 2. Where did they get the average energy required to break/form the bonds? Alright, so for the first one. Draw out the lewis structures of each of the reactants and products. On ...
by AtreyiMitra2L
Fri Jan 12, 2018 11:10 am
Forum: Phase Changes & Related Calculations
Topic: Work done BY vs. Work done ON [ENDORSED]
Replies: 5
Views: 231

Re: Work done BY vs. Work done ON [ENDORSED]

This is how I think about it. Imagine work as the direction of the push. If the push is on the system (such as compression as the volume is becoming smaller), it would be work done on the system. Because work is done on the system, we know the work must be done by the surroundings. If the push is on...
by AtreyiMitra2L
Fri Jan 12, 2018 11:06 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Type of system for mercury in thermometer
Replies: 5
Views: 329

Re: Type of system for mercury in thermometer

It would be a closed system. In a closed system, there is a transfer of energy but not of matter. Because it's in a tube, the mercury can't escape. But it can respond by changes in volume based on the transfer of energy through heat. Therefore, its a closed system.
by AtreyiMitra2L
Fri Jan 12, 2018 11:05 am
Forum: Phase Changes & Related Calculations
Topic: Expansion and change in pressure
Replies: 4
Views: 179

Expansion and change in pressure

So I was working on a problem that had to do with expansion and a subsequent lower internal energy. The question asked if the pressure of the gas would be higher or lower when these changes are completed. I was under the assumption that because there is an inverse relationship between pressure and v...
by AtreyiMitra2L
Fri Jan 12, 2018 11:01 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Ideal Gases
Replies: 1
Views: 94

Ideal Gases

Why is it that with ideal gases, there is no change in internal energy? Thank you!
by AtreyiMitra2L
Wed Jan 10, 2018 9:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.73a
Replies: 1
Views: 100

8.73a

In this question, we are supposed to use bond enthalpies to estimate the reaction enthalpy for 3C2H2(g)-->C6H6(g). In the solutions manual, it says that only 6 C H bonds are formed (where the bond is between a single and double). It seems to me that 4 C - H bonds are formed as well. Can someone plea...
by AtreyiMitra2L
Wed Jan 10, 2018 9:30 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Most Stable Form for an Element
Replies: 4
Views: 205

Re: Most Stable Form for an Element

i believe it means the way it sounds. the state it is most likely to be found in nature
by AtreyiMitra2L
Mon Jan 08, 2018 10:43 pm
Forum: Phase Changes & Related Calculations
Topic: Question 8.25
Replies: 4
Views: 215

Re: Question 8.25

The rest of the question is not important. The question is asking us only to find the change in internal energy. Therefore, we should only be looking for changes in q and w. We find c (the heat capacity) so that we can use this value later to multiply it by the temperture change in the second experi...
by AtreyiMitra2L
Mon Jan 08, 2018 10:39 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy and Temperature [ENDORSED]
Replies: 4
Views: 198

Re: Enthalpy and Temperature [ENDORSED]

Today in class we learned that enthalpy is related to heat. Given that temperture is defined as the average kinetic energy of particles, this definition does not make it hard to understand why the two may be correlated.
by AtreyiMitra2L
Mon Jan 08, 2018 10:37 pm
Forum: Phase Changes & Related Calculations
Topic: Question on 8.21
Replies: 3
Views: 127

Re: Question on 8.21

In this question, you have to understand that the heat released by one will be absorbed by the other. Consequently, you will use -q(copper) = q(water). The initial temp of copper is 100 C and the initial temp of water 22 C. Because you know the masses and can find the specific heat, you should autom...
by AtreyiMitra2L
Mon Jan 08, 2018 10:32 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb and Coffee Cup Calorimeter [ENDORSED]
Replies: 3
Views: 200

Bomb and Coffee Cup Calorimeter [ENDORSED]

How is the volume fixed in the bomb calorimeter and not in the coffee cup calorimeter?
by AtreyiMitra2L
Sat Dec 09, 2017 11:04 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Question in adding H20 in equilibrium reaction
Replies: 2
Views: 292

Re: Question in adding H20 in equilibrium reaction

yes i am confused by this too. a similar question was on one of the modules 15. The photosynthesis reaction, 6 CO2(g) + 6 H2O(l) ⇌ C6H12O6(aq) + 6 O2(g), is endothermic. What effect will the following changes have on the equilibrium composition. a) Water is added. b) The partial pressure of CO2 is d...
by AtreyiMitra2L
Sat Dec 09, 2017 1:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Practice Test Fall 2017 [ENDORSED]
Replies: 19
Views: 2020

Re: Practice Test Fall 2017 [ENDORSED]

on worksheet 9 number 1, the question says that x is the equilbrium concentration of so2. I understand that you have to balance the equation, but I don't understand equilbrium concentration would go from x to 2x when the question said that it should be x. Why is it that is is written as 2x instead?
by AtreyiMitra2L
Fri Dec 08, 2017 8:27 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Pd electron configuration
Replies: 2
Views: 256

Pd electron configuration

I was working on the 2013 final exam and one of the questions said that the electron configuration for Pd is [Kr]4d10. Can someone explain to me how this is the case?
by AtreyiMitra2L
Wed Dec 06, 2017 10:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: ClF3 Lewis acid/ base?
Replies: 2
Views: 415

ClF3 Lewis acid/ base?

Is ClF3 a lewis acid or base and why?
by AtreyiMitra2L
Sun Dec 03, 2017 11:45 pm
Forum: Sigma & Pi Bonds
Topic: Difference between Bonds [ENDORSED]
Replies: 7
Views: 455

Re: Difference between Bonds [ENDORSED]

yes this is correct.
by AtreyiMitra2L
Sun Dec 03, 2017 11:44 pm
Forum: Ideal Gases
Topic: Q and K [ENDORSED]
Replies: 35
Views: 1073

Re: Q and K [ENDORSED]

The formulas are the exact same.
by AtreyiMitra2L
Sun Dec 03, 2017 11:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium
Replies: 3
Views: 202

Re: Chemical Equilibrium

The solvent is what dissolves the solute. It is usually a liquid in this class. The universal solvent is water. However, it can also be a gas or supercritical fluid. The solvent can not be aqueous as an aqueous solution means that the solvent was water.
by AtreyiMitra2L
Sun Dec 03, 2017 11:41 pm
Forum: Octet Exceptions
Topic: Expanded Octet Rules
Replies: 7
Views: 448

Re: Expanded Octet Rules

Expanded octets become a possibility at 3p. It becomes a possibility bc 3d is right above it. This sub shell can hold more electrons which is why atoms like P, S, and Cl can hold an expanded octet.
by AtreyiMitra2L
Tue Nov 28, 2017 11:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc vs. Kp
Replies: 3
Views: 205

Re: Kc vs. Kp

If the units are already in pressure and it just says k, then you should keep the units in pressure. If the units are already in molarity and it just says k, then you should keep the units in molarity. If it says kc, then make sure to have the units be in molarity. With Kp, have the units be in pres...
by AtreyiMitra2L
Tue Nov 28, 2017 11:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K and Kc
Replies: 7
Views: 259

Re: K and Kc

When it says Kc, you should be finding the concentrations in molarity. When it says k, if the units are pressure, keep it in pressure. If the units are in molarity, keep it in molarity.
by AtreyiMitra2L
Mon Nov 27, 2017 10:44 am
Forum: Naming
Topic: Ligand order in coordination sphere
Replies: 3
Views: 150

Ligand order in coordination sphere

Hello, I am very confused about the order of the ligands within the coordination sphere. When I asked Dr. Lavelle in class, he said that the order didn't matter. This idea is reaffirmed throughout chemistry community. However, within the textbook, it says that the chemical symbols of the ligands sho...
by AtreyiMitra2L
Mon Nov 27, 2017 10:21 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles (help please) [ENDORSED]
Replies: 3
Views: 262

Bond angles (help please) [ENDORSED]

Hello. I am still confused about certain bond angles. I posted this elsewhere but I want to say it again to highlight the discord. This what I feel it to be. Sea-saw : <90, <120, <180 T-structure : <90, <120, <180 Square pyramidal : <90 Square planar : 90 Can someone please verify these all of these...
by AtreyiMitra2L
Mon Nov 27, 2017 9:40 am
Forum: Naming
Topic: 17.31 c and d confusion
Replies: 5
Views: 326

Re: 17.31 c and d confusion

Hi Mike, How water is written does not matter, so long as it is correctly written with two hydrogens and one oxygen. H2O and OH2 are equally correct. For part d., because oxalate has the prefix bis-, this has higher priority than "diaqua" as b precedes d. Hope this helps. But I thought th...
by AtreyiMitra2L
Sun Nov 26, 2017 11:45 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework Help 11.59
Replies: 2
Views: 142

Re: Homework Help 11.59

First, you would have to change moles to molar concentrations. Then you would put all your initial molar concentrations in your ice chart. Then for change, based on the coefficients of the reactants and products, subtract/add the coefficient x x. You subtract for the reactants and add for the produc...
by AtreyiMitra2L
Sun Nov 26, 2017 11:42 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Unequal Reactant
Replies: 3
Views: 166

Re: Unequal Reactant

When there are more reactants than products, the equilibrium sits to the left. This is because the denominator of the K expression is larger than the numerator, which leads to a K value that is less than one meaning that the equilibrium sits to the left. Actually, K is actually not affected by the ...
by AtreyiMitra2L
Sun Nov 26, 2017 11:38 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordinatiom compound vs TM complex
Replies: 1
Views: 90

Re: Coordinatiom compound vs TM complex

Chem_mod said in a different post that they are interchangeable.
by AtreyiMitra2L
Sun Nov 26, 2017 11:37 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Relation between K and Q
Replies: 2
Views: 260

Re: Relation between K and Q

Remember with K and Q products is over reactants. When Q is less than K, we know that must mean that there are more reactants at this point in the system. If there are more reactants, then the reaction will have the tendency to shift to the products. In terms of Gibbs free energy, the outline says t...
by AtreyiMitra2L
Sun Nov 26, 2017 11:35 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium
Replies: 3
Views: 123

Re: Chemical Equilibrium

Are there any specific exceptions we should be aware of for Chemical Equilibrium (in some other chapters there are specific exceptions to know, like chromium and copper for the orbitals)? I suppose one would be if you yield two positive values from your quadratic, you are two use the value of X tha...
by AtreyiMitra2L
Sun Nov 26, 2017 11:31 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs. K
Replies: 3
Views: 164

Re: Q vs. K

Alissa Stanley 3G wrote:So it is possible for Q and K to be equal, if Q is at equilibrium?


Yes! If Q and K are equal, we know that the mixture has equilibrium composition and has no tendency to change in either direction.
by AtreyiMitra2L
Sun Nov 26, 2017 11:30 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: How can you determine if a complex is a polydentate?
Replies: 5
Views: 316

Re: How can you determine if a complex is a polydentate?

You determine if its polydentate if there are multiple atoms that have lone pairs on them that can form a coordinate covalent bond. A rule of thumb is that whenever you have Nitrogens, you are sure that the molecule is polydentate. Because there are two nitrogens as there is in ethylenediamine (en) ...
by AtreyiMitra2L
Sun Nov 26, 2017 11:24 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs. K
Replies: 3
Views: 164

Re: Q vs. K

Q can be the concentrations of the reactants and products at any point in the reaction. K can only be the concentrations of the reactants at equilibrium. You go about solving them the same way. By using both Q and K, we can determine which way the reaction is more likely to proceed.
by AtreyiMitra2L
Sun Nov 26, 2017 11:17 am
Forum: Naming
Topic: 17.1
Replies: 1
Views: 106

Re: 17.1

Well 17.1 was unassigned and unrelated to what we will be tested on so I assume you meant 17.29? Lewis structures aren't needed. This pdf is very helpful with naming compounds. Memorize it. https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/NamingCoordinationCompounds.pdf The charges ...
by AtreyiMitra2L
Sun Nov 26, 2017 11:11 am
Forum: Naming
Topic: Naming (steps)
Replies: 6
Views: 258

Re: Naming (steps)

RenuChepuru1G wrote:at what point should you figure out cations versus anions and is there an easy way to do that?


The cations are what has an overall positive charge and the anions are what has an overall negative charge.
by AtreyiMitra2L
Sun Nov 26, 2017 11:04 am
Forum: Student Social/Study Group
Topic: Chapter 17
Replies: 1
Views: 224

Re: Chapter 17

by AtreyiMitra2L
Sun Nov 26, 2017 11:03 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium
Replies: 3
Views: 123

Re: Chemical Equilibrium

Yes, but it would still be a good idea to do practice problems to familiarize yourself with the topics. Sometimes through practice, you learn exceptions that teachers won't directly teach you.

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