Search found 20 matches

by Kiara Quinn 3B
Sun Mar 19, 2017 9:28 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Strain difference
Replies: 1
Views: 388

Re: Strain difference

Torsional Strain is a force that opposes rotation of a part of a molecule about a bond whereas steric strain occurs when there is a non bonded interaction that is too close together. For example, in the boat conformation, there would be a lot of steric strain due to the flagpole interactions. Torsio...
by Kiara Quinn 3B
Sun Mar 12, 2017 5:14 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Prefix naming
Replies: 3
Views: 414

Re: Prefix naming

Just adding on, in the organic chemistry textbook it also clarifies which should be italicized and hyphenated on page 24: "A note on good practice: Sec- and tert- are prefixes, they are italicized and hyphenated and they are ignored in alphabetizing substituents. Unlike iso and neo, which are p...
by Kiara Quinn 3B
Sat Mar 04, 2017 11:01 am
Forum: *Alkanes
Topic: Substituents
Replies: 4
Views: 337

Re: Substituents

Is the number of substituents limited to the number of carbons on the parent chain? I think you are right. A substituent is an atom or group of atoms that replaces hydrogen atoms on the parent chain of a hydrocarbon so I think from what we've talked about so far the number is limited to the number ...
by Kiara Quinn 3B
Fri Feb 24, 2017 5:50 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Intermediate and Transition States
Replies: 3
Views: 433

Re: Intermediate and Transition States

Today during lecture, Professor Lavelle explained that there is one main distinction between the two:

Transition states have partially formed bonds, whereas intermediates have full formed bonds. (see page 85 in the course reader)
by Kiara Quinn 3B
Tue Feb 14, 2017 11:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Textbook Question 14.13b
Replies: 1
Views: 159

Textbook Question 14.13b

When writing the cell diagram for this, the solution manual states that "An inert electrode such as Pt is necessary when both oxidized and reduced species are in the same solution." How do I know just by looking at the equation whether or not they are in the same solution? Thanks.
by Kiara Quinn 3B
Fri Feb 10, 2017 6:40 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 6
Views: 752

Re: Salt Bridge

In the book it asks which salts you definitely cannot use for a salt bridge, but I'm not exactly sure which those would be. I know that ions should not affect the cell reaction, and that KCl is a common one used, but I am not sure which salts you would avoid and why.
by Kiara Quinn 3B
Fri Feb 03, 2017 1:23 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Homework Problem #9.15
Replies: 1
Views: 244

Re: Homework Problem #9.15

I think the -6.01 kJ/mol is the heat of fusion of water. The values from appendix 2A only tell you the enthalpy of formation and the gibbs free energy of formation. But since this is a phase change you want to use delta H fusion like we did on page 15 of the course reader. The heating curve there sh...
by Kiara Quinn 3B
Fri Jan 27, 2017 5:31 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Questions Not Found in Book By Adam Perez, Dis 1L
Replies: 1
Views: 203

Re: Questions Not Found in Book By Adam Perez, Dis 1L

Most of these questions seem more like physics problems. For i) to calculate the kinetic energy you can use the equation KE= 1/2mv^2. For ii) to calculate the gravitational potential energy you can use PE=mgh. For iii) to calculate elastic potential energy I believe you use the equation PE=1/2kx^2 w...
by Kiara Quinn 3B
Sun Jan 22, 2017 4:01 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: delta G vs. delta Gr
Replies: 1
Views: 380

delta G vs. delta Gr

In Chapter 11.3 on page 429, it states "A Note on Good Practice: It is important to distinguish between the chemical amount n, which has the unit mol, and nr, the stoichiometric coefficient, which is a pure number" Is this similar to the difference between standard reaction enthalpy and st...
by Kiara Quinn 3B
Sat Jan 14, 2017 5:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta H subscripts
Replies: 3
Views: 904

Re: Delta H subscripts

The subscripts are used to help specify what you are solving for. It can be helpful to make the distinction between standard reaction enthalpy and the standard enthalpy of formation. The subscript of f tells you we are looking for the standard enthalpy of formation, which means we will want to know ...
by Kiara Quinn 3B
Sat Dec 03, 2016 9:36 pm
Forum: *Titrations & Titration Calculations
Topic: What is the correct number of significant figures for 13.27(b)?
Replies: 3
Views: 605

Re: What is the correct number of significant figures for 13.27(b)?

For sig figs with logs we have to look at the mantissa, which is basically everything after the decimal point. So, for this we calculated the pOH using -log (.0667). The mantissa in this is .0667 which means you will have 4 sig figs i your final answer. This is why we get 14.00-1.176 (4 sig figs) to...
by Kiara Quinn 3B
Sat Dec 03, 2016 8:58 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Finding the pH at the halfway point
Replies: 1
Views: 438

Re: Finding the pH at the halfway point

For the halfway point to the stoichiometric point, I think you use pH=pKa.
by Kiara Quinn 3B
Wed Nov 16, 2016 1:03 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Identifying Polydentates? [ENDORSED]
Replies: 8
Views: 911

Re: Identifying Polydentates? [ENDORSED]

Why is H2O always monodenate?
by Kiara Quinn 3B
Wed Nov 09, 2016 8:28 pm
Forum: Ideal Gases
Topic: Using Kc vs Kp
Replies: 3
Views: 517

Re: Using Kc vs Kp

Would there be a case in which you would have to use both Kc and Kp at the same time?
by Kiara Quinn 3B
Fri Nov 04, 2016 8:50 pm
Forum: Properties of Light
Topic: What to do when a Energy is given in kJ*mol-1?
Replies: 6
Views: 753

Re: What to do when a Energy is given in kJ*mol-1?

In terms of memorizing the wavelengths, just remember that 400 nm is violet and 700 nm is red. Anything slightly less than 400 nm would be in the UV region. Anything slightly greater than 700 nm is infrared region.
by Kiara Quinn 3B
Fri Oct 28, 2016 3:09 pm
Forum: Lewis Structures
Topic: Lewis Structure of CO
Replies: 1
Views: 253

Lewis Structure of CO

In the textbook, the Lewis structure for CO had a triple bond between C and O, and both C and O had one lone pair. This gave a total of 10 electrons, where C had a formal charge of -1 and O had a formal charge of +1. I am confused about why the Lewis structure is not a double bond between C and O wh...
by Kiara Quinn 3B
Fri Oct 21, 2016 1:38 pm
Forum: Lewis Structures
Topic: Lewis Structure for BF3
Replies: 1
Views: 709

Re: Lewis Structure for BF3

Boron is one of the exceptions to the octet rule. This is because on the periodic table Boron only has 3 valence electrons to begin with. Therefore, having three single bonds, sharing 1 electron per bond, BF3 is a stable compound.
by Kiara Quinn 3B
Wed Oct 12, 2016 9:48 pm
Forum: Molarity, Solutions, Dilutions
Topic: diluted solution
Replies: 1
Views: 221

Re: diluted solution

Yes, for the first part you can use MV=MV or you can use dimensional analysis. Both will give you the same result. For the second question just cancel units:

.400 mol/L x .675 L =.27 mol K2SO4

Since there are 2 K^+ for every K2SO4, there would be .540 mol of K^+ in the final solution.
by Kiara Quinn 3B
Mon Oct 03, 2016 1:11 pm
Forum: Empirical & Molecular Formulas
Topic: Workbook: Quiz 1 2015 #5 Find empirical formula [ENDORSED]
Replies: 1
Views: 445

Re: Workbook: Quiz 1 2015 #5 Find empirical formula [ENDORSED]

Most likely, you did not multiply the moles of H2O by 2 to get moles of H. Starting from the beginning, the first step is find how many moles of C and H there are in the compound. To do so we divide the masses of CO2 and H2O by their respective molar masses: (8.80 g CO2)/(12.01g/mol + 2 (16 g/mol O)...
by Kiara Quinn 3B
Mon Sep 26, 2016 5:27 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Fundamental E, E.23, Part D
Replies: 1
Views: 344

Re: Fundamental E, E.23, Part D

I think you may have just calculated it wrong. When you plug the following into your calculator, you should get 286.148g: 2 (molar mass of Na) + molar mass of C + 3 (molar mass of O) + 20 (molar mass of H) + 10 (molar mass of O) 2 (22.99g) + 12.011 g + 3 (15.99 g) + 20 (1.008g) + 10 (15.99g) From th...

Go to advanced search