## Search found 62 matches

Sun Mar 17, 2019 8:37 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: OH- in cell diagram
Replies: 1
Views: 226

### OH- in cell diagram

Can we include OH- in our cell diagrams? Thank you.
Sun Mar 17, 2019 8:36 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Difference between ΔG and ∆Go
Replies: 1
Views: 255

### Difference between ΔG and ∆Go

What is the difference between ΔG and ∆Go? is there a difference between the following equations: ΔG=w and ∆Go=w? Thank you.
Sat Mar 16, 2019 9:35 am
Forum: Phase Changes & Related Calculations
Topic: Bond Enthalpies
Replies: 3
Views: 274

### Bond Enthalpies

When solving bond enthalpies, what role do coefficients play? How do coefficients affect how we solve bond enthalpy problems? Thank you.
Sat Mar 16, 2019 9:09 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Problem 9.13 Sixth edition
Replies: 1
Views: 279

### Re: Problem 9.13 Sixth edition

They most probably used Cp = (5/2)*R because this HW problem had specific heat at constant pressure (not constant volume).
Sat Mar 16, 2019 9:03 am
Forum: Phase Changes & Related Calculations
Topic: moles / mass in phase change problems
Replies: 3
Views: 325

### Re: moles / mass in phase change problems

For phase changes, we usually solve in mols since the equation includes n(change in)Hfusion or n(change in)Hvaporization. The "n" in these equations represent number of mols.
Sat Mar 16, 2019 9:00 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Ecell Values
Replies: 3
Views: 307

### Re: Ecell Values

E cell does not become multiplied by any coefficient, it remains the same.
Sat Mar 16, 2019 8:58 am
Forum: Ideal Gases
Topic: SI Units
Replies: 3
Views: 326

### Re: SI Units

atm is the unit most commonly used.
Sat Mar 16, 2019 8:57 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: units in regards to C
Replies: 1
Views: 291

### Re: units in regards to C

Any constant in general does not have units because it is a ratio.
Sat Mar 16, 2019 8:55 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium constant
Replies: 5
Views: 137

### Re: Equilibrium constant

A catalyst only speeds up a reaction rate, but has no direct effect on the equilibrium constant.
Sat Mar 16, 2019 8:53 am
Forum: *Enzyme Kinetics
Topic: kprime and k1
Replies: 2
Views: 313

### Re: kprime and k1

K is your forward rate and k' is your reverse rate, so yes, there are differences among the two.
Sat Mar 16, 2019 8:51 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram - Water
Replies: 2
Views: 91

### Cell Diagram - Water

When drawing a cell diagram, do we include H20(l) at all? If we do include it in our diagram, are there any exceptions as to when we do or do not include them? Thank you.
Fri Mar 15, 2019 6:56 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: HW 4A.11
Replies: 1
Views: 269

### HW 4A.11

Why is it that in the 7th edition HW 4A.11, the answer key solved the problem in K but the book gave us the variables in degrees C? There was no conversion between degrees C and K, the answer key just solved it using the the numbers as given. Thank you.
Fri Mar 15, 2019 6:54 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: q cal versus q reaction
Replies: 1
Views: 313

### q cal versus q reaction

What are the differences and similarities between heat (q) in a reaction and heat (q) in a calorimeter? Thank you.
Thu Mar 14, 2019 10:32 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: When to use quadratic equation
Replies: 2
Views: 294

### When to use quadratic equation

What criteria allows us to solve problems using just equilibrium constants or the quadratic formula? Thank you.
Thu Mar 14, 2019 10:29 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: HW 5I.33 7th edition
Replies: 1
Views: 232

### HW 5I.33 7th edition

In the 7th edition homework problem 5I.33, why do we not use an ICE chart to solve?
Thu Mar 14, 2019 10:27 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Percentages in HW problems
Replies: 1
Views: 238

### Percentages in HW problems

When solving certain homework questions, such as 5I.19 (7th edition), how do we solve when given a certain percentage of a compound exists at equilibrium? Thank you
Thu Mar 14, 2019 10:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ice chart coefficients
Replies: 1
Views: 91

### Ice chart coefficients

In an ICE chart, how do we know when to put coefficients for our "-x" or "+x"'s in the "C" row? Thank you.
Thu Mar 14, 2019 10:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ice chart
Replies: 2
Views: 103

### ice chart

When making an ice chart, when do you know to add or subtract in the "C" row? Thank you.
Tue Mar 12, 2019 7:59 pm
Forum: Balancing Redox Reactions
Topic: Coefficients
Replies: 3
Views: 213

### Coefficients

Do coefficients affect oxidation numbers? Thank you.
Fri Mar 08, 2019 9:15 pm
Forum: General Rate Laws
Topic: Coefficients and Products
Replies: 1
Views: 106

### Coefficients and Products

When we are given an equation with coefficients and multiple products, how do we write the differential rate law? Thank you.
Fri Mar 08, 2019 9:14 pm
Forum: General Rate Laws
Topic: coefficient question
Replies: 2
Views: 115

### coefficient question

When writing differential rate laws and we are given coefficients in our equation, how do we go about writing the rate law? How does having coefficients present affect rate law? Thank you.
Fri Mar 08, 2019 9:11 pm
Forum: First Order Reactions
Topic: Homework 7B.3 part C
Replies: 1
Views: 98

### Homework 7B.3 part C

Does anyone know how to solve homework 7B.3 part C step by step from the 7th edition textbook? I am having difficulty understanding how to solve when given a concentration from the products instead of the reactants. Thank you.
Wed Feb 06, 2019 8:47 pm
Forum: Phase Changes & Related Calculations
Topic: Symbol inquiry
Replies: 4
Views: 177

### Symbol inquiry

Does change in U = internal energy or does just U by itself = internal energy? I am confused as to which symbol is the correct one to represent internal energy? Thank you.
Sat Jan 26, 2019 8:14 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Calculating Q
Replies: 11
Views: 820

### Re: Calculating Q

Put simply, Q is calculated when the reaction is not at equilibrium.
Sat Jan 26, 2019 8:11 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q VS. K
Replies: 13
Views: 780

### Re: Q VS. K

Yes, both are solved in the same way. Once both values are found, compare both to see if Q=K, which means the solution is at equilibrium.
Sat Jan 26, 2019 8:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pH
Replies: 9
Views: 436

### Re: pH

pH=-log[H3O+] or pH=-log[H+]
Please note that anything with brackets means "concentration of".
Sat Jan 26, 2019 8:05 pm
Forum: Ideal Gases
Topic: OH and H3O
Replies: 10
Views: 674

### Re: OH and H3O

Simply put, anything with OH- is a base and anything with H30+ or H+ is an acid.
Sat Jan 26, 2019 8:03 pm
Forum: Ideal Gases
Topic: ICE table
Replies: 11
Views: 634

### Re: ICE table

ICE tables may be used for both cases. They are also helpful in comparing Q with K to check equilibrium.
Sat Jan 26, 2019 8:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 217
Views: 115293

### Re: Advice from a Medical Student[ENDORSED]

Sat Jan 26, 2019 7:57 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE Box Ratios
Replies: 8
Views: 448

### ICE Box Ratios

May someone please explain the ratios for the ice boxes that we do? How does "-x" work with ratios? Thank you.
Thu Jan 17, 2019 11:13 pm
Forum: Ideal Gases
Topic: Q and K Graph Explanation
Replies: 2
Views: 117

### Q and K Graph Explanation

Does anyone remember the Q and K bar graph Dr. Lavelle explained in his slides? May someone please explain the bar graph and its patterns. Thank you.
Thu Jan 17, 2019 11:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Thermodynamic Stability HW 5I.13
Replies: 2
Views: 117

### Thermodynamic Stability HW 5I.13

When solving HW problem 5I.13, it asked to see which is more "thermodynamically stable"? What is meant by thermodynamic stability? What determines its stability? Thank you.
Wed Dec 05, 2018 9:16 pm
Forum: Naming
Topic: Polyatomic ions and naming
Replies: 7
Views: 212

### Re: Polyatomic ions and naming

I know some are already expected of us to know. Overall, my TA said its highly recommended that you do know them.
Wed Dec 05, 2018 9:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape
Replies: 5
Views: 249

### Re: Shape

Yes, we always write the molecular geometry because it gives a more accurate shape name than electronic geometry.
Wed Dec 05, 2018 9:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent Structures
Replies: 12
Views: 421

### Re: Bent Structures

I believe it will be appropriate to say so if electronegative difference exists, resulting in polarity.
Wed Dec 05, 2018 9:05 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: “Soapy” feel of bases
Replies: 5
Views: 653

### Re: “Soapy” feel of bases

Also, to add on, bases are alkaline and as long they are so, a "soapy" feel of bases will result
Wed Dec 05, 2018 9:04 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 11221

### Re: FINAL PRACTICE - Lyndon's Churro Review Session[ENDORSED]

Thank you so much for having taken the time to create a review packet for us Lyndon! Appreciate it!
Wed Dec 05, 2018 9:02 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Number
Replies: 7
Views: 259

### Re: Coordination Number

Coordination # = number of ligands bonded to central atom
Oxidation # = charge on central atom
Wed Dec 05, 2018 9:00 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: HW for this week
Replies: 4
Views: 190

### Re: HW for this week

Yes, and just in case if you will need a kind reminder of which problems, here they are:

7th Edition Unit 5
Focus 9C.1 and 9C.2 Problems 9C: 1,3,5,7,9

7th Edition Unit 6
Fundamentals J Problems 1,7,9,11,13,17,23
Wed Dec 05, 2018 8:57 pm
Forum: Naming
Topic: Coordination Number and Central Atoms
Replies: 1
Views: 109

### Coordination Number and Central Atoms

Can you find coordination numbers with 2 central atoms? if so, how? If not, why not? Thank you.
Wed Dec 05, 2018 8:54 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Intermolecular Forces (Melting Pts.)
Replies: 2
Views: 816

### Re: Intermolecular Forces (Melting Pts.)

To add on, as atomic size increases, surface area of the atom also increases, leading to a higher melting point for CHI3 rather than CHF3.
Wed Nov 28, 2018 8:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Electron Geometry and Molecular Geometry
Replies: 2
Views: 175

### Re: Electron Geometry and Molecular Geometry

You will need to write the molecular geometry only.
Wed Nov 28, 2018 8:09 pm
Forum: Lewis Structures
Topic: Lewis Structure Use
Replies: 1
Views: 94

### Lewis Structure Use

Are lewis structures only used for covalent bonds or are they also used for ionic bonds as well? Thank you.
Wed Nov 28, 2018 8:08 pm
Forum: Dipole Moments
Topic: Magnitude
Replies: 2
Views: 105

### Magnitude

What is exactly meant by the term magnitude in the definition of a dipole? Thank you.
Mon Nov 26, 2018 9:46 pm
Forum: Hybridization
Topic: HW 2.59 Question
Replies: 2
Views: 152

### Re: HW 2.59 Question

Hey Brian, thank you so much for your help!
Mon Nov 26, 2018 7:13 pm
Forum: Hybridization
Topic: HW 2.59 Question
Replies: 2
Views: 152

### HW 2.59 Question

On the 2.59 homework, how do we write the composition of bonds and hybridization of lone pairs for H2C=CHCHO when you have a double bond with one pi and one sigma bond? I am having difficulty understanding, for example, how to reach one of the answers of sigma (C2sp^2,O2sp^2) pi(C2p, O2p). Also, how...
Mon Nov 26, 2018 4:51 pm
Forum: Hybridization
Topic: Homework 2F.1 Question
Replies: 1
Views: 143

### Homework 2F.1 Question

For unit 4 HW, question 2F.1, when we are asked to write the relative orientations of the hybrid orbitals, may we just write their molecular geometry (tetrahedral or linear or t-shape)? Is saying, for example, tetrahedral, the same as tetrahedron? Is there a difference between relative orientation a...
Sun Nov 25, 2018 8:56 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8047
Views: 1413043

### Re: Post All Chemistry Jokes Here

A: What's the formula for water?
B: H I J K L M N O
A: That's wrong!
B: Nope, the formula is H to O
Sun Nov 25, 2018 8:50 pm
Forum: Sigma & Pi Bonds
Topic: Sigma Bond vs. Pi Bond
Replies: 2
Views: 106

### Re: Sigma Bond vs. Pi Bond

Sigma bonds can be rotated because they interact end to end with one electron bonded end to end. Because this electron is bonded end to end makes it possible for the sigma bond to rotate without breaking. On the other hand, pi bonds interact side to side with one electron bonded side to side, making...
Sun Nov 25, 2018 8:45 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Lone Pairs
Replies: 5
Views: 468

### Re: Lone Pairs

Lone pairs have great repulsion strength from one another, always trying to move as far apart as possible while keeping an equally distributed distance from the central atom.
Sun Nov 25, 2018 8:39 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: labeling hybridization
Replies: 3
Views: 131

### labeling hybridization

How would you label/draw hybridization if you had BF3?
Sun Nov 25, 2018 8:36 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: linear vs bent question
Replies: 7
Views: 314

### linear vs bent question

How come for trigonal planar geometry and for tetrahedral geometry if the number of bonded electrons (coordination number) is 2, the molecular geometry is bent but for trigonal bipyramidal when the number of bonded electrons is 2, the molecular geometry is linear - not bent? Thank you in advance!
Wed Nov 14, 2018 11:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Thanksgiving [ENDORSED]
Replies: 14
Views: 615

### Re: Thanksgiving[ENDORSED]

This past Saturday we received an email mentioning how we are done with outline 3 and will be starting outline 4 throughout this week in hopes of not having lecture next week. I would assume we are ahead enough where no lecture will be needed next week. Good luck with travel plans!
Wed Nov 14, 2018 11:26 pm
Forum: Ionic & Covalent Bonds
Topic: general question about polarity of bonds
Replies: 1
Views: 127

### Re: general question about polarity of bonds

If the molecule is polar, then yes, triple and double bonds have more polarity than a single bond. Also, a triple bond has more polarity than a double bound, if you were to compare the two together. Hope this helps!
Wed Nov 14, 2018 11:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Coordination Number
Replies: 1
Views: 104

### Coordination Number

Is it possible to have a coordination number that's 1? Why or why not? Thank you.
Wed Nov 14, 2018 11:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing structures
Replies: 4
Views: 125

### Drawing structures

When trying to draw the structure of NH3, will this structure have that triangular shaped wedge at any given time? I ask so because I know that the central atom, N, ends up with a lone pair, but am not sure if that triangular shaped wedge would be appropriate. Thank you.
Fri Nov 09, 2018 5:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Symbol meanings between chemical bonds
Replies: 2
Views: 116

### Symbol meanings between chemical bonds

When drawing the shape of a compound, what do the dashed signs ("||||||") between elements and the dark triangular signs (▲) mean? Thank you.
Fri Nov 09, 2018 5:05 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Boiling point
Replies: 12
Views: 626

### Re: Boiling point

To add on, spherical shaped molecules have lower boiling points, usually 10°C, and rod shaped molecules have higher boiling points, usually 36°C.
Fri Nov 09, 2018 4:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Strength of H2S
Replies: 1
Views: 66

### Bond Strength of H2S

I was interested in knowing if H2S is polar or nonpolar? Why? Also, is it dipole or not? Why? The differences among the two have been confusing me. Thank you!
Thu Nov 01, 2018 12:12 am
Forum: Lewis Structures
Topic: Double bonds [ENDORSED]
Replies: 3
Views: 135

### Re: Double bonds[ENDORSED]

When dealing with a limited number of valence electrons, you turn to double bonds to add more flexibility when wanting to achieve octets. For example, when given the compound ONF, first we find its valence electrons. O has 6, N has 5, F has 7, all of which total to 18. Now you know your limited numb...
Thu Nov 01, 2018 12:01 am
Forum: Ionic & Covalent Bonds
Topic: p block atoms
Replies: 4
Views: 169

### Re: p block atoms

From the best of my knowledge, I know that if that element is either in or after row 3, it may have more than an octet. Also, if an element is usually past the atomic number of 20, it may have more than an octet as well. Hope this helps.
Wed Oct 31, 2018 11:57 pm
Forum: Lewis Structures
Topic: HW Problem 2B.9 Part B
Replies: 1
Views: 91

### HW Problem 2B.9 Part B

The HW question gives K3P compound and asks for Lewis Structure to be written? Would anyone know why the final answer is spaced out in such a way? Also, would anyone know why only P has brackets around it, but not K? Thank you in advance!