Search found 74 matches

by Tyra Nguyen 4H
Sun Mar 10, 2019 3:28 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Mechanisms
Replies: 1
Views: 27

Re: Reaction Mechanisms

The problem should provide us this information. If not, the slow step is the rate-determining step, thus the slow step will match the overall rate law. It honestly depends on the context but if you were just given the mechanism and nothing else I don't think you would be able to figure out because i...
by Tyra Nguyen 4H
Sun Mar 10, 2019 3:26 pm
Forum: First Order Reactions
Topic: Half Life for First Order
Replies: 3
Views: 46

Re: Half Life for First Order

From page 628 of the 6th edition textbook

ln2 will simplify to 0.693, which is the equation given on the provided formula sheet on tests.
by Tyra Nguyen 4H
Sun Mar 10, 2019 3:23 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Microscopic Reversibility
Replies: 2
Views: 42

Re: Microscopic Reversibility

Microscopic reversibility: The mechanism of a reversible reaction is exactly the same (but reversed) for both the forward and backward version of the reaction. The transition states for each mechanism step are identical regardless of reaction direction.

from the chem.ucla.edu site!
by Tyra Nguyen 4H
Sun Mar 10, 2019 3:21 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 15.63 Units with ln?
Replies: 1
Views: 29

15.63 Units with ln?

15.63 The rate constant of the reaction between CO2 and OH - in aqueous solution to give the HCO3 - ion is 1.5 x 1010 L.mol -1 s -1 at 25 o C. Determine the rate constant at blood temperature (37 o C), given that the activation energy for the reaction is 38 kJ.mol -1 . I got the right answer, but I ...
by Tyra Nguyen 4H
Wed Mar 06, 2019 5:18 pm
Forum: General Rate Laws
Topic: Mechanisms?
Replies: 3
Views: 55

Mechanisms?

What does Dr. Lavelle mean when he refers to "reaction mechanisms?"
by Tyra Nguyen 4H
Wed Feb 27, 2019 6:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Given standard reduction potentials [ENDORSED]
Replies: 2
Views: 41

Re: Given standard reduction potentials [ENDORSED]

Why is the standard reaction potential not flipped for 14.23 part a? The reaction is : 2NO 3 - (aq) + 8H + (aq) + 6Hg (l) --> 3Hg 2 2+ (aq) + 2NO (g) + 4 H 2 O (l). The given standard reaction potential for the anode is Hg 2 2+ (aq) --> Hg (l), with standard reaction potential of 0.79, but this is n...
by Tyra Nguyen 4H
Wed Feb 27, 2019 6:14 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Given standard reduction potentials [ENDORSED]
Replies: 2
Views: 41

Given standard reduction potentials [ENDORSED]

We are given standard reduction potentials for half-reactions. Do we flip the sign of these half-reactions when we want the result for an oxidation reaction, as the equation itself flips?
by Tyra Nguyen 4H
Wed Feb 27, 2019 5:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.15(c) Cell Diagram
Replies: 1
Views: 42

Re: 14.15(c) Cell Diagram

I think it is similar to Au and Ag, which are also typically metals used as electrodes. I believe we only use Pt (s) when there is no given metal in the solid phase.
by Tyra Nguyen 4H
Wed Feb 27, 2019 5:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.15, part a (6th edition) [ENDORSED]
Replies: 1
Views: 44

14.15, part a (6th edition) [ENDORSED]

14.15 Write the half-reactions and devise a galvanic cell (write a cell diagram) to study each of the following reactions: (a) AgBr(s) --> Ag + (aq) + Br - (aq) Why does the solution manual give an answer for the anode as "AgBr(s) --> Ag (aq) + Br - (aq)" I thought that the anode was where...
by Tyra Nguyen 4H
Wed Feb 27, 2019 2:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.116th edition part e
Replies: 1
Views: 25

Re: 14.116th edition part e

Because Sn4+ and Sn2+ are apart of the anode reaction, this indicates that it is an oxidation reaction. An oxidation reaction must "release" an electron, as oxidation is loss of an electron. Thus, the oxidation half-reaction is Sn4+ --> Sn2+ + 2e-
by Tyra Nguyen 4H
Wed Feb 27, 2019 2:12 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.11 6th edition, part D
Replies: 2
Views: 38

14.11 6th edition, part D

4.11 Write the half-reactions and the balanced equation for the cell reaction for each of the following galvanic cells: (d) Pt(s)|O 2 (g)|H + (aq)||OH - (aq)|O 2 (g)|Pt(s) Are O 2 (g) and H + (aq) the reactants of the oxidation half-reaction (as seen in solutions manual)? I am not sure how to go abo...
by Tyra Nguyen 4H
Mon Feb 25, 2019 10:54 am
Forum: Balancing Redox Reactions
Topic: Balancing Charges
Replies: 4
Views: 62

Re: Balancing Charges

Screen Shot 2019-02-25 at 10.53.35 AM.png
I just don't really understand what this is trying to say? It appears to me that the molecule on the left has an oxidation number of -5, but why is it -7?
by Tyra Nguyen 4H
Mon Feb 25, 2019 10:48 am
Forum: Balancing Redox Reactions
Topic: Balancing Charges
Replies: 4
Views: 62

Balancing Charges

Example 14.1 in the textbook says to balance MnO4-(aq) +H2C2O4(aq) Mn2+(aq) + CO2(g) and for the reduction half reaction, it indicates that MnO4-Mn2+. How do we know that the charge of O4- is -2, as stated in the textbook?
by Tyra Nguyen 4H
Wed Feb 20, 2019 5:40 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 9.55, 6th edition (part c)
Replies: 2
Views: 60

9.55, 6th edition (part c)

Question 9.55 asks you to write a balanced chemical equation for the formation reaction of various gases. In part C, it asks you to do so for CO(g). Why do you use C(s, graphite) for the chemical equation and not C(s, diamond) or C(g)? Is C(s, graphite) the most stable form of carbon?
by Tyra Nguyen 4H
Sun Feb 10, 2019 6:23 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: when to use kj and kj.mol^-1
Replies: 2
Views: 52

when to use kj and kj.mol^-1

When do I know when to use kJ or kJ.mol-1 when talking about enthalpy, whether it be standard reaction enthalpy or standard enthalpy of formation, etc.?
by Tyra Nguyen 4H
Sun Feb 10, 2019 9:33 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: adding an inert gas
Replies: 4
Views: 167

adding an inert gas

Why does adding an inert gas not affect the reaction?
by Tyra Nguyen 4H
Sat Feb 09, 2019 9:02 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: what does enthalpy mean in 8.49 (6th)
Replies: 1
Views: 53

what does enthalpy mean in 8.49 (6th)

OF 2 (g) + H 2 O(g) ---> O 2 (g) + 2HF(g) and \Delta H = -318kJ What is the change in internal energy for the reaction of 1.00 mol OF2? What does the \Delta H = -318kJ mean in this particular problem? I know what the standard reaction enthalpy is but how does it differ from this question? Do I have ...
by Tyra Nguyen 4H
Fri Feb 08, 2019 9:04 pm
Forum: Calculating Work of Expansion
Topic: Which P to use? 6th edition, 8.27
Replies: 3
Views: 70

Which P to use? 6th edition, 8.27

8.27 Calculate the work for each of the following processes beginning with a gas sample in a piston assembly with T = 305 K, P = 1.79 atm, and V = 4.29 L: (a) irreversible expansion against a constant external pressure of 1.00 atm to a final volume of 6.52 L; (b) isothermal, reversible expansion to ...
by Tyra Nguyen 4H
Fri Feb 08, 2019 6:39 pm
Forum: Calculating Work of Expansion
Topic: Conversions to joules?
Replies: 4
Views: 89

Conversions to joules?

8.3 Air in a bicycle pump is compressed by pushing in the handle. If the inner diameter of the pump is 3.0 cm and the pump is depressed 20. cm with a pressure of 2.00 atm, (a) how much work is done in the compression? (b) Is the work positive or negative with respect to the air in the pump? (c) What...
by Tyra Nguyen 4H
Thu Feb 07, 2019 1:37 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: when to solve for specific vs. molar heat capacity
Replies: 2
Views: 56

Re: when to solve for specific vs. molar heat capacity

I believe that we will typically use heat the specific heat capacity. Unless we deal specifically with moles, I would not use molar heat capacity to make it easier in terms of units. The formula to calculate the heat released is q = m*C* \Delta T. To calculate the heat capacity, C, for a constant pr...
by Tyra Nguyen 4H
Thu Feb 07, 2019 1:18 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Midterm topics
Replies: 3
Views: 81

Re: Midterm topics

We do not go in the order of the textbook. This is what was on the outlines located on Dr. Lavelle's website: Outline 1: 7th Edition: Focus 5G-J (Omit 5G.3, 5G.4, and pages 432-433) Outline 2: 7th Edition: Focus 6A.4; 6B; 6C.1-6C.2; 6D; 6E.1; Box 6E.1 Outline 3: 7th Edition: Focus 4A-4D.5; 4E3 Outli...
by Tyra Nguyen 4H
Thu Feb 07, 2019 1:15 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work
Replies: 4
Views: 70

Re: Work

When the work of a system is positive, it means that the system is doing work. This can be seen as the gas in a container expanding, pushing a piston. The system is expanding, thus is doing work.

Conceptually, positive work means that work is being done by a system.
by Tyra Nguyen 4H
Thu Feb 07, 2019 1:10 pm
Forum: Bronsted Acids & Bases
Topic: CH3COOH acid/base identifying
Replies: 1
Views: 133

Re: CH3COOH acid/base identifying

I believe that typically when a molecule contains a nitrogen, it will accept a proton and create the hydroxide ion. If not, then the molecule it will donate the proton to create a hydronium ion. You should probably memorize the few strong acids though, like HCl. Secondly, you don't have to include t...
by Tyra Nguyen 4H
Thu Feb 07, 2019 1:07 pm
Forum: Phase Changes & Related Calculations
Topic: sections
Replies: 4
Views: 76

Re: sections

"Chemical Equilibrium, Acid and Base Equilibria, Thermochemistry, Thermodynamics to the end of entropy" which is essential outlines 1 through 4!
by Tyra Nguyen 4H
Wed Feb 06, 2019 7:04 pm
Forum: Calculating Work of Expansion
Topic: 6th edition 8.27 part b
Replies: 3
Views: 70

Re: 6th edition 8.27 part b

The volume should be 4.29L, not the final volume, since you want to find the number of moles at the start of the expansion. I plug this in and my answer is 3.068 x 10 -5 mols. Plugging in the rest of the numbers, I get the work to be -0.3J which is very off from the -326 it is supposed to be. What ...
by Tyra Nguyen 4H
Wed Feb 06, 2019 6:57 pm
Forum: Calculating Work of Expansion
Topic: 6th edition 8.31
Replies: 3
Views: 64

6th edition 8.31

8.31 Calculate the heat released by 5.025 g of Kr(g) at
0.400 atm as it cools from 97.6 oC to 25.0 oC at (a) constant pressure and (b) constant volume. Assume that krypton behaves as an ideal gas.

I don't really know where to start with this problem or what equations to even use.
by Tyra Nguyen 4H
Wed Feb 06, 2019 6:49 pm
Forum: Calculating Work of Expansion
Topic: 6th edition 8.27 part b
Replies: 3
Views: 70

6th edition 8.27 part b

8.27 Calculate the work for each of the following processes beginning with a gas sample in a piston assembly with T = 305 K, P = 1.79 atm, and V = 4.29 L: (a) irreversible expansion against a constant external pressure of 1.00 atm to a final volume of 6.52 L; (b) isothermal, reversible expansion to ...
by Tyra Nguyen 4H
Fri Feb 01, 2019 12:52 pm
Forum: Calculating Work of Expansion
Topic: Maximum expansion work?
Replies: 2
Views: 43

Maximum expansion work?

I don't really understand why work done during a reversible expansion of gas is the maximum expansion work possible. I understand the difference between irreversible expansion and reversible expansion but how does this relate to "maximum expansion work"?
by Tyra Nguyen 4H
Fri Feb 01, 2019 9:57 am
Forum: Phase Changes & Related Calculations
Topic: 8.13 (6th Edition) Homework Question
Replies: 1
Views: 50

Re: 8.13 (6th Edition) Homework Question

Right so you have the equation U = q + w, then moving the variables around to solve for work you have w = U - q. Since the internal energy is -2573kJ, you have w= -2573kJ - q. Because the cylinder surrounding the fuel is absorbing the energy, that means q = -947kJ, because the system, fuel, loses he...
by Tyra Nguyen 4H
Wed Jan 30, 2019 7:46 pm
Forum: Calculating Work of Expansion
Topic: 6th edition, 8.9
Replies: 1
Views: 38

6th edition, 8.9

The question is as follows: 8.9 An ideal gas in a cylinder was placed in a heater and gained 5.50 kJ of energy as heat. If the cylinder increased in volume from 345 mL to 1846 mL against an atmospheric pressure of 750. Torr during this process, what is the change in internal energy of the gas in the...
by Tyra Nguyen 4H
Wed Jan 23, 2019 8:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6th edition, 12.69
Replies: 3
Views: 57

Re: 6th edition, 12.69

So the first step is to take off a Cl from the compound, because it's an ionic compound and ionic compounds fully dissociate. So for NH 4 Cl, it would turn into NH 4 + . Then do the chemical equation if you added H 2 O to the ion. The products should be NH 3 and H 3 O + . From there you can do an I...
by Tyra Nguyen 4H
Wed Jan 23, 2019 5:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6th edition, 12.69
Replies: 3
Views: 57

6th edition, 12.69

Not sure how to approach this problem, as the Kb values aren't given in any tables?:

Calculate the pH of each of the following solutions: (a) 0.19 m NH4Cl(aq); (b) 0.055 m AlCl3(aq).
by Tyra Nguyen 4H
Wed Jan 23, 2019 12:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6th edition, 12.57
Replies: 1
Views: 59

6th edition, 12.57

(a) When the pH of 0.10 m HClO2(aq) was measured, it was found to be 1.2. What are the values of Ka and pKa of chlorous acid? (b) The pH of a 0.10 m propylamine, C3H7NH2, aqueous solution was measured as 11.86. What are the values of Kb and pKb of propylamine? I am stuck on this question. I calculat...
by Tyra Nguyen 4H
Wed Jan 23, 2019 10:35 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6th edition, 12.33
Replies: 3
Views: 62

Re: 6th edition, 12.33

Hi! So using the 17.78 M OH from part b, you can use that and the balanced equation to work backwards. Because NaOH is a strong base, it will completely dissociate, meaning that [OH] = [Na] = [NaOH]. If we have 17.78 M [OH], the we have 17.78 M [NaOH]. The equation is Na2O + H2O ----> 2NaOH If we h...
by Tyra Nguyen 4H
Wed Jan 23, 2019 10:33 am
Forum: Ideal Gases
Topic: atm vs. bar?
Replies: 23
Views: 423

atm vs. bar?

What's the difference between atm and bar when calculating the equilibrium constant with pressure?
by Tyra Nguyen 4H
Wed Jan 23, 2019 10:10 am
Forum: Ideal Gases
Topic: Units for concentration
Replies: 5
Views: 82

Re: Units for concentration

yes
by Tyra Nguyen 4H
Wed Jan 23, 2019 10:09 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: All products are solids
Replies: 3
Views: 75

Re: All products are solids

I don't think that solids can be in equilibrium? The molar concentration of a solid does not change, thus they are just represented as 1 in the equilibrium constant.
by Tyra Nguyen 4H
Wed Jan 23, 2019 10:05 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6th edition, 12.33
Replies: 3
Views: 62

6th edition, 12.33

The question is as follows: A student added solid Na2O to a 200.0-mL volumetric flask, which was then filled with water, resulting in 200.0 mL of NaOH solution. 5.00 mL of the solution was then transferred to another volumetric flask and diluted to 500.0 mL. The pH of the diluted solution is 13.25. ...
by Tyra Nguyen 4H
Tue Jan 15, 2019 5:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.43 6th edition
Replies: 4
Views: 80

11.43 6th edition

The question states: Consider the reaction 2NO(g) \rightleftharpoons N 2 (g)+O 2 (g). If the initial partial pressure of NO(g) is 1.0 bar, and x is equilibrium concentration of N 2 (g), what is the correct equilibrium relation? (a) K=x 2 /(1.0-x) (b) K=x 2 (c) K=x 2 /(1.0-2x) 2 (d) K=4x 2 /(1.0-2x) ...
by Tyra Nguyen 4H
Tue Jan 15, 2019 5:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and liquids in equilibrium constants?
Replies: 2
Views: 43

Solids and liquids in equilibrium constants?

Can someone please explain why solids and liquids are not included in the calculation of an equilibrium constant? The textbook is a little confusing in its explanation.
by Tyra Nguyen 4H
Tue Jan 15, 2019 5:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.39 6th edition
Replies: 4
Views: 100

Re: 11.39 6th edition

There is a table earlier in the chapter which is needed for reference in this problem. The table will give you the equilibrium constant, K, at various temperatures for specific equilibrium reactions, such as H 2 (g)+Cl 2 \rightleftharpoons 2HCl (g). Knowing the specific equilibrium constants of thes...
by Tyra Nguyen 4H
Sun Jan 13, 2019 9:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Question 11.11
Replies: 1
Views: 40

Re: Question 11.11

There would be different concentrations of O 3 and O 2 because there are different amounts of starting moles (.10-mol compared with 0.5-mol). The difference in starting moles while keeping the same liter size yields a difference in concentration, as concentration is calculated with moles/liter. the ...
by Tyra Nguyen 4H
Thu Jan 10, 2019 2:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference between C and P?
Replies: 4
Views: 57

Difference between C and P?

When looking at equilibrium reactions where there are products and reactants in a gas state, how do I know when to use molar concentration (with square brackets in equilibrium constant equations) or the partial pressure (P in equilibrium constant equations)? I understand that it often depends on the...
by Tyra Nguyen 4H
Thu Jan 10, 2019 2:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6th edition, 11.7?
Replies: 4
Views: 113

6th edition, 11.7?

The question comes with an image of 4 flasks illustrating the 4 stages towards the dissociation of a diatomic molecule, X 2 , over time until the reaction reaches equilibrium. Part c of the question asks, "Assuming that the initial pressure of X 2 was 0.10 bar, calculate the value of K for the ...
by Tyra Nguyen 4H
Fri Dec 07, 2018 5:41 pm
Forum: Amphoteric Compounds
Topic: Difference between amphoteric and amphiprotic?
Replies: 4
Views: 98

Difference between amphoteric and amphiprotic?

What are the difference between the two?
by Tyra Nguyen 4H
Fri Dec 07, 2018 5:39 pm
Forum: Administrative Questions and Class Announcements
Topic: test questions
Replies: 1
Views: 60

test questions

How many questions are on this final?
by Tyra Nguyen 4H
Tue Dec 04, 2018 9:01 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate and Coordination Number?
Replies: 2
Views: 85

Polydentate and Coordination Number?

If a ligand was tridentate, does that mean that the complex would have a coordination number of 3? Similarly, if a ligand was bidentate, would its coordination number be 2?
by Tyra Nguyen 4H
Tue Nov 27, 2018 4:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs. Nonpolar? (Q25, C4, 6th edition)
Replies: 1
Views: 41

Polar vs. Nonpolar? (Q25, C4, 6th edition)

I'm still confused on how to determine dipole moments, especially within a polyatomic molecule. For example, the referenced question asks whether or not the molecule CH2Cl2 is polar or non-polar. How do I know which direction the dipole moments are pointing in?
by Tyra Nguyen 4H
Tue Nov 27, 2018 4:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polarity vs. nonpolarity
Replies: 8
Views: 145

Re: polarity vs. nonpolarity

Drawing the Lewis Structure usually helps! Once you draw the structure you can see if there is a net dipole moment - if there is one then it is polar. A helpful tip though is that C bonded to H is always nonpolar. Also, if the Lewis Structure is symmetric, it is usually nonpolar because the dipoles...
by Tyra Nguyen 4H
Sun Nov 25, 2018 2:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Chapter 4, Question 7 (6th Edition)
Replies: 1
Views: 25

Chapter 4, Question 7 (6th Edition)

I understand part a, where the molecular shape SOCl 2 is trigonal pyramidal. However, how are OSCl and ClSCl also trigonal pyramidal? Part C of question 7 asks the values of their bond angles, giving the answer to be less than 109 o , but there are only 3 atoms thus I thought the answer would be les...
by Tyra Nguyen 4H
Sun Nov 25, 2018 2:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Planar or Trigonal Pyramidal?
Replies: 4
Views: 82

Trigonal Planar or Trigonal Pyramidal?

How do you know which shape is which? For example, SO32- has an electron arrangement that is tetrahedral, but its molecular shape is trigonal pyramidal. Why is it not trigonal planar?
by Tyra Nguyen 4H
Sun Nov 25, 2018 2:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: pi and sigma bonds
Replies: 9
Views: 149

Re: pi and sigma bonds

There is a greater extent of orbital overlap in a sigma bond, thus it is a stronger bond that requires more energy to break.
by Tyra Nguyen 4H
Sun Nov 25, 2018 2:15 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 5
Views: 112

Re: Polarizability

Polarization is the process where an electron cloud of an anion is distorted due to a small, highly charged cation being close to a larger anion. Cations with a small radius, thus being highly charged have high polarizing power, meaning that they can cause the largest distortions of a polarizable an...
by Tyra Nguyen 4H
Sun Nov 25, 2018 2:11 pm
Forum: Hybridization
Topic: Hybrid orbitals pointing to corners?
Replies: 4
Views: 88

Re: Hybrid orbitals pointing to corners?

But how do you know which corner it is pointing to? Does this relate to the dipole moments?
by Tyra Nguyen 4H
Wed Nov 21, 2018 10:22 am
Forum: Hybridization
Topic: Hybrid orbitals pointing to corners?
Replies: 4
Views: 88

Hybrid orbitals pointing to corners?

Was reading the textbook and didn't understand what this meant: "(a) An s-orbital and a p-orbital hybridize into two sp hybrid orbitals that point in opposite directions, forming a linear molecular shape. (b) An s-orbital and two p-orbitals can blend together to give three sp 2 hybrid orbitals ...
by Tyra Nguyen 4H
Wed Nov 14, 2018 4:32 pm
Forum: Administrative Questions and Class Announcements
Topic: Grades
Replies: 5
Views: 161

Re: Grades

My RA said that last year Dr. Lavelle set the average as a B and went from there.
by Tyra Nguyen 4H
Wed Nov 14, 2018 4:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: What to memorize in VSEPR?
Replies: 8
Views: 174

Re: What to memorize in VSEPR?

Most likely the bond angles too! Dr.Lavelle said we would have to know how SO32- has a repulsion strength of less than the expected trigonal pyramidal shape of 109.5o due to its lone pair repulsion, so I'm assuming we also have to know the other basic bond angles.
by Tyra Nguyen 4H
Wed Nov 14, 2018 4:28 pm
Forum: Lewis Structures
Topic: Boron Trifluoride
Replies: 8
Views: 153

Re: Boron Trifluoride

I believe Boron is an exception to the octet rule! Just something to memorize:)
by Tyra Nguyen 4H
Wed Nov 14, 2018 4:24 pm
Forum: Ionic & Covalent Bonds
Topic: Contribution to the resonance structure?
Replies: 3
Views: 119

Contribution to the resonance structure?

I was reading the textbook (6th Edition, page 90, section 3.12), and it described the resonance hybrid structure of a Cl 2 molecule. The textbook states that "the ionic structures make only a small contribution to the resonance hybrid; the bond is almost purely covalent" but I don't really...
by Tyra Nguyen 4H
Thu Nov 01, 2018 9:00 pm
Forum: Ionic & Covalent Bonds
Topic: 6th edition, 3.19b
Replies: 1
Views: 42

6th edition, 3.19b

The electron configuration of Ni2+ is [Ar]3d8, so why is the number of unpaired electrons 2?
by Tyra Nguyen 4H
Thu Nov 01, 2018 3:12 pm
Forum: Ionic & Covalent Bonds
Topic: 6th edition, 3.11
Replies: 1
Views: 22

6th edition, 3.11

I do not understand this. Please help me understand! Thanks
by Tyra Nguyen 4H
Thu Nov 01, 2018 3:08 pm
Forum: Administrative Questions and Class Announcements
Topic: Questions on Midterm
Replies: 4
Views: 120

Questions on Midterm

Professor Lavelle's slide said that the question on the midterm would be from homework, chemistry community, and online assessments -- do you guys think that the midterm questions are restricted to only these?
by Tyra Nguyen 4H
Thu Nov 01, 2018 3:05 pm
Forum: Ionic & Covalent Bonds
Topic: 6th Edition, 3.5
Replies: 1
Views: 70

6th Edition, 3.5

I understand how Cu+ is [Ar]3d10, but I don't understand parts b, c, and d? I think the f-block throws me off, but can anybody explain them? Thanks!
by Tyra Nguyen 4H
Wed Oct 24, 2018 4:13 pm
Forum: Einstein Equation
Topic: 6th Edition, Question 1.55
Replies: 2
Views: 206

6th Edition, Question 1.55

Anybody know how to do question 1.55, part c? The wording of the question is slightly confusing to me, where it says "absorbing at 3500 cm-1".
by Tyra Nguyen 4H
Mon Oct 22, 2018 12:02 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electron density?
Replies: 4
Views: 66

Electron density?

Why is electron density important?
by Tyra Nguyen 4H
Mon Oct 22, 2018 12:00 pm
Forum: Properties of Light
Topic: Visible Light Spectrum... ?
Replies: 6
Views: 119

Re: Visible Light Spectrum... ?

We just need to know it for UV and visible light (I went to Lavelle's office hours and that was what he said :))
by Tyra Nguyen 4H
Tue Oct 16, 2018 4:25 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Planck's Constant
Replies: 4
Views: 58

Re: Planck's Constant

The only part where significant figures matter is the answer.
by Tyra Nguyen 4H
Tue Oct 16, 2018 4:22 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Community Questions Due Date
Replies: 7
Views: 121

Re: Chemistry Community Questions Due Date

My TA said by Sunday night at the end of the week (may differ from TA to TA because it depends on when they check I guess).
by Tyra Nguyen 4H
Fri Oct 12, 2018 1:11 pm
Forum: Photoelectric Effect
Topic: Variable for frequency
Replies: 6
Views: 92

Variable for frequency

Is there another variable that is used to represent frequency? It can be confusing when E=hv and Ek=(1/2)meve2 and the v is also velocity.
by Tyra Nguyen 4H
Fri Oct 12, 2018 1:05 pm
Forum: DeBroglie Equation
Topic: Angstrom?
Replies: 8
Views: 182

Angstrom?

What is an Angstrom and how is it applied in the lab?
by Tyra Nguyen 4H
Wed Oct 10, 2018 10:52 am
Forum: Empirical & Molecular Formulas
Topic: Question F13 ??
Replies: 2
Views: 151

Question F13 ??

"In an experiment, 4.14 g of phosphorus combined with chlorine to produce 27.8 g of a white solid compound. (a) What is the empirical formula of the compound? (b) Assuming that the empirical and molecular formulas of the compound are the same, what is its name?" Anybody know how to figure ...
by Tyra Nguyen 4H
Thu Oct 04, 2018 4:56 pm
Forum: Molarity, Solutions, Dilutions
Topic: V=n/c
Replies: 7
Views: 106

Re: V=n/c

During Professor Lavelle's lecture, he also said that he would use M to represent molarity concentration. However, in the textbook (at least in the 6th edition), molarity concentration is represented as the variable "c".
by Tyra Nguyen 4H
Thu Oct 04, 2018 4:50 pm
Forum: Limiting Reactant Calculations
Topic: Question 7 on Module 1 Post-Assessment [ENDORSED]
Replies: 2
Views: 94

Question 7 on Module 1 Post-Assessment [ENDORSED]

Question: Nicotine has mass percentage composition 74.03% C, 8.70% H, and 17.27% N, and a molar mass of 162.23 g/mol. Determine the molecular formula. I'm struggling to answer this question, as I keep getting the ratio of C:H:N to be 5.7:7.9:1 and cannot solve for the empirical formula. None of the ...
by Tyra Nguyen 4H
Thu Oct 04, 2018 4:10 pm
Forum: SI Units, Unit Conversions
Topic: Homework Questions [ENDORSED]
Replies: 14
Views: 250

Re: Homework Questions [ENDORSED]

By the end of Week 2, we are supposed to have completed the "Photoelectric Effect", "Atomic Spectra and the Bohr Frequency Condition", "Wave Properties of Electrons and the De Broglie Equation", and "Heisenberg Uncertainty Equation" modules!

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