Search found 110 matches

by Racquel Fox 2I
Sat Mar 13, 2021 8:52 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Control of Reactions
Replies: 3
Views: 23

Control of Reactions

I am getting really confused on how to tell whether a reaction is controlled by kinetics or thermodynamics. How do you easily tell?
by Racquel Fox 2I
Sat Mar 13, 2021 11:03 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Effect of pH
Replies: 3
Views: 14

Effect of pH

7.23 (a) What is the overall reaction for the following mechanism? ClO− +H2O⇌HClO +OH− (fast equilibrium) HClO+I-→HIO+Cl− (very slow) HIO+OH−⇌IO−+H2O (fast equilibrium) (c) How will the reaction rate depend on the pH of the solution? I'm confused how to answer this question. I got k2k1/k'1[ClO-][I-]...
by Racquel Fox 2I
Sat Mar 13, 2021 1:03 am
Forum: Student Social/Study Group
Topic: Distractions
Replies: 15
Views: 96

Re: Distractions

I'm in a similar situation. I had a family emergency on Monday night, and I've been finding it really hard to focus on my studies. I think the best thing to remember is that, while it is important, the grades you get on your finals don't define who you are and your level of intelligence. It's tough ...
by Racquel Fox 2I
Wed Mar 10, 2021 4:00 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Textbook 6M.5
Replies: 5
Views: 44

Re: Textbook 6M.5

You put platinum on the side when the reaction doesn't contain a solid
by Racquel Fox 2I
Tue Mar 09, 2021 2:04 pm
Forum: General Rate Laws
Topic: Final Exam
Replies: 15
Views: 61

Re: Final Exam

The final will be cumulative, so definitely prepare for everything we've learned this quarter.
by Racquel Fox 2I
Mon Mar 08, 2021 11:03 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Textbook 6N.1 Part B
Replies: 1
Views: 21

Textbook 6N.1 Part B

6N.1) Calculate the equilibrium constants for the following reactions:
(b) In3+(aq) + U3+(aq)⇌In2+(aq) + U4+(aq)

The solution manual says that n=2, and gives the equation In3+ + 2e- --> In2+.
I thought n would equal 1, because in order to equal the charge to In2+, In3+ only needs one electron?
by Racquel Fox 2I
Mon Mar 08, 2021 5:21 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Textbook 6L.5 Part D
Replies: 1
Views: 33

Textbook 6L.5 Part D

Write the half-reactions, the balanced equation for the cell reaction, and the cell diagram for each of the following skeletal equations:
(d) Au+ (aq)→ Au(s) + Au3+(aq)

How do you know that Au is in both the oxidation and reduction half reactions if it's only on the product side of the equation?
by Racquel Fox 2I
Mon Mar 08, 2021 10:35 am
Forum: Second Order Reactions
Topic: Textbook 7A.17 pt C and D
Replies: 2
Views: 39

Textbook 7A.17 pt C and D

7A.17) The following data were obtained for the reaction A + B + C → products: c) Determine the value of the rate constant. d) Use the data to predict the reaction rate for Experiment 5. I think I'm doing the calculations for these parts right, but I'm getting very off units for my answers. I got 2....
by Racquel Fox 2I
Sun Mar 07, 2021 8:30 pm
Forum: General Science Questions
Topic: Final Exam
Replies: 39
Views: 224

Re: Final Exam

There are going to be a bunch of UA sessions for either general review or particular sections of the course. I definitely recommend going to as many as possible! Dr. Lavelle sent an email with all of the times a couple days ago.
by Racquel Fox 2I
Sun Mar 07, 2021 8:28 pm
Forum: First Order Reactions
Topic: Equation Confusion
Replies: 15
Views: 69

Equation Confusion

I keep getting confused on whether to use the [A] = -kt + [A]0 equation or the ln[A] = -kt + ln[A]0.
How do you distinguish when either equation is necessary?
by Racquel Fox 2I
Thu Mar 04, 2021 1:19 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Constructing Cell Diagrams
Replies: 4
Views: 18

Constructing Cell Diagrams

I'm a little confused when to put Pt (s) in the cell diagram. Is there a specific rule for when it is necessary?
by Racquel Fox 2I
Sun Feb 28, 2021 6:49 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Sapling #12
Replies: 2
Views: 29

Sapling #12

Calculate the standard free-energy change for the reaction at 25 ∘C. Refer to the list of standard reduction potentials. 2Au3+(aq)+3Mg(s)↽−−⇀2Au(s)+3Mg2+(aq) I don't know what I'm doing wrong with this problem. I calculated the Ecathode to be 2.996 and Eanode to be 7.14 and then plugged in Ecell int...
by Racquel Fox 2I
Sat Feb 27, 2021 5:37 pm
Forum: Balancing Redox Reactions
Topic: Sapling #5
Replies: 1
Views: 37

Sapling #5

Identify the oxidizing and reducing agents in the skeletal (unbalanced) reaction. Then, balance the reaction, including the phase (solid, liquid, etc.) of each species. The reaction takes place in basic aqueous solution. [Pb(OH)4]2−(aq)+ClO−(aq)⟶PbO2(s)+Cl−(aq) When I did this problem, I believe I t...
by Racquel Fox 2I
Wed Feb 17, 2021 1:07 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Standard Conditions
Replies: 8
Views: 30

Standard Conditions

Hypothetically, if there was a question where deltaH and deltaS are given and you want to solve for deltaG, would you assume that T is 25 degrees C ?
by Racquel Fox 2I
Wed Feb 17, 2021 11:34 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Textbook 5J.15
Replies: 5
Views: 31

Textbook 5J.15

Calculate the equilibrium constant at 25 °C and at 150 °C for each of the following reactions, using data available in Appendix 2A:
a) NH4Cl (s) <--> NH3 (g) + HCl (g)

I understand how to find K for 25 degrees, but I'm not getting the right answer for 150 degrees. Is there a step I'm missing?
by Racquel Fox 2I
Wed Feb 17, 2021 11:18 am
Forum: Student Social/Study Group
Topic: Sapling on midterm 2
Replies: 6
Views: 55

Re: Sapling on midterm 2

I think all of the Week 5/6 Sapling is on the midterm, and probably whatever was on the Week 3/4 Sapling that wasn't covered on MT1.
by Racquel Fox 2I
Wed Feb 17, 2021 11:18 am
Forum: Student Social/Study Group
Topic: Sapling on midterm 2
Replies: 6
Views: 55

Re: Sapling on midterm 2

I think all of the Week 5/6 Sapling is on the midterm, and probably whatever was on the Week 3/4 Sapling that wasn't covered on MT1.
by Racquel Fox 2I
Tue Feb 16, 2021 11:21 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Textbook 4H.9
Replies: 2
Views: 38

Textbook 4H.9

Container A is filled with 1.0 mol of the atoms of an ideal monatomic gas. Container B has 1.0 mol of atoms bound together as diatomic molecules that are not vibrationally active. Container C has 1.0 mol of atoms bound together as diatomic molecules that are vibrationally active. The containers all ...
by Racquel Fox 2I
Mon Feb 15, 2021 7:40 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Sapling Homework #15
Replies: 3
Views: 24

Sapling Homework #15

Given the information A+B ⟶2D ΔH∘=648.4 kJ ΔS∘=347.0 J/K C⟶D ΔH∘=569.0 kJ ΔS∘=−116.0 J/K calculate ΔG∘ at 298 K for the reaction A+B⟶2C I'm a little confused because I felt like I understood this problem and got -626.1 as the answer. I approached this with Hess's law, and then used ΔG=ΔH∘ - TΔS∘
by Racquel Fox 2I
Mon Feb 15, 2021 5:48 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2
Replies: 14
Views: 88

Re: Midterm 2

I'm pretty sure there will be some partial credit!
by Racquel Fox 2I
Mon Feb 15, 2021 5:48 pm
Forum: Student Social/Study Group
Topic: Studying for Midterm 2
Replies: 45
Views: 261

Re: Studying for Midterm 2

The UA workshops are amazing and help give you more test-like problems. Also make sure you completely understand your work for the textbook problems and you will be fine! Good luck!
by Racquel Fox 2I
Mon Feb 15, 2021 5:46 pm
Forum: Student Social/Study Group
Topic: Silly Mistakes?
Replies: 61
Views: 449

Re: Silly Mistakes?

This was really great to read. I think it's so easy to be really hard on yourself for a subpar test score, but it helps to put things in perspective.
by Racquel Fox 2I
Mon Feb 15, 2021 5:45 pm
Forum: Student Social/Study Group
Topic: Midterm 2 Nerves
Replies: 40
Views: 192

Re: Midterm 2 Nerves

I feel the same way, I feel like I should feel more prepared than I can, but it's important to remember to stay calm about the midterm. All we can do is put our best effort in, so if you feel like you have prepared as best as you can, all you can do is calm yourself down so your nerves don't affect ...
by Racquel Fox 2I
Mon Feb 15, 2021 5:43 pm
Forum: Van't Hoff Equation
Topic: Van't Hoff [ENDORSED]
Replies: 6
Views: 117

Re: Van't Hoff [ENDORSED]

The Van't Hoff equation is used to calculate K at different temperatures if deltaH is known
by Racquel Fox 2I
Thu Feb 11, 2021 7:15 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Using Cp and Cv
Replies: 3
Views: 41

Using Cp and Cv

Do you only use the ideal gas values for Cp and Cv for the entropy equation with a change in temperature?
by Racquel Fox 2I
Thu Feb 11, 2021 7:08 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Week 5 and 6 Sapling #3
Replies: 2
Views: 28

Week 5 and 6 Sapling #3

This questions asks to classify the phase changes by the signs of the system's deltaH and deltaS, and I'm a little confused on how you find out if the change in entropy is positive or negative for different phase changes.
by Racquel Fox 2I
Wed Feb 10, 2021 7:21 pm
Forum: Calculating Work of Expansion
Topic: How to Know When to use Cp and Cv
Replies: 4
Views: 36

How to Know When to use Cp and Cv

I've been having some trouble knowing when to use the 5/2R for Cp and 3/2R for Cv unless its explicitly stated. What are some clues to know?
by Racquel Fox 2I
Wed Feb 10, 2021 5:02 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy: kJ or J?
Replies: 30
Views: 108

Entropy: kJ or J?

Should entropy be solved for kJ/K or J/K? I noticed that a lot of the given q values are in kJ but the answers are in J.
by Racquel Fox 2I
Mon Feb 08, 2021 11:46 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy
Replies: 2
Views: 7

Entropy

This might be a dumb question but can entropy ever be negative? Or does the absolute value of T make it always positive?
by Racquel Fox 2I
Sun Feb 07, 2021 2:20 pm
Forum: Administrative Questions and Class Announcements
Topic: tips if you're struggling!
Replies: 77
Views: 486

Re: tips if you're struggling!

Thank you so much for these tips! I think my studying habits have definitely improved since 14A, but it is great to hear more I can do to do well in this class.
by Racquel Fox 2I
Sun Feb 07, 2021 2:18 pm
Forum: Student Social/Study Group
Topic: Studying When You Don't Want to
Replies: 48
Views: 203

Re: Studying When You Don't Want to

I completely understand where you are coming from. Honestly, the best thing you can do when you're feeling that way is to take a break and take care of yourself. If you are doing work when you're feeling really overwhelmed, you are not going to get your best work done. So it best to just take a chil...
by Racquel Fox 2I
Sun Feb 07, 2021 2:16 pm
Forum: Administrative Questions and Class Announcements
Topic: 14bl virtual or in person
Replies: 13
Views: 95

Re: 14bl virtual or in person

I'm in a similar position, but I think I'm going to take 14BL next quarter online because I want to finish the chemistry series faster.
by Racquel Fox 2I
Sun Feb 07, 2021 2:15 pm
Forum: Student Social/Study Group
Topic: Chemistry Community Posts
Replies: 12
Views: 67

Re: Chemistry Community Posts

My number of posts varies between one more and one less that the number of posts I have. I just try to reload the page often, and when checking, go to your posts and view the number you have and if the page is refreshed it should be accurate.
by Racquel Fox 2I
Sun Feb 07, 2021 1:44 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Sapling Homework #20
Replies: 6
Views: 40

Sapling Homework #20

I'm really confused on how to start this problem from the week 3 and 4 sapling homework. If anyone could help me I would really appreciate it. A 0.201 mol sample of Ar(g) initially at 298 K and 1.00 atm is held at constant volume while enough heat is applied to raise the temperature of the gas by 11...
by Racquel Fox 2I
Wed Feb 03, 2021 6:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Tips for Concentrating during a test
Replies: 31
Views: 140

Re: Tips for Concentrating during a test

It's definitely a lot harder to focus with all exams online now. I find even when my testing area is completely quiet it's hard for me to focus. I've been working on practicing more mindfulness and trying to study without music because even though it helps me tune out and focus, I think its hard for...
by Racquel Fox 2I
Sun Jan 31, 2021 8:08 pm
Forum: Administrative Questions and Class Announcements
Topic: Grading for Chemistry Community Posts
Replies: 13
Views: 115

Re: Grading for Chemistry Community Posts

I wouldn't worry too much about the content, I think the purpose of posting is to further your learning by asking questions you're confused about/answering other people's questions to help you understand it even better! We only have to post 5 posts a week.
by Racquel Fox 2I
Sun Jan 31, 2021 8:06 pm
Forum: Student Social/Study Group
Topic: Go treat yourself after MT1!
Replies: 75
Views: 357

Re: Go treat yourself after MT1!

Thank you! It's nice to hear that kind of validation sometimes! I took a break from school after the midterm on Friday to unwind.
by Racquel Fox 2I
Sun Jan 31, 2021 8:05 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 1
Replies: 9
Views: 88

Re: Midterm 1

Typically around a week!
by Racquel Fox 2I
Tue Jan 26, 2021 10:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: textbook. practice problem 5I.3
Replies: 1
Views: 6

Re: textbook. practice problem 5I.3

The temperature is given at 500K, and the K=794 is for when temperature is 298 K.
by Racquel Fox 2I
Tue Jan 26, 2021 9:51 pm
Forum: Student Social/Study Group
Topic: Midterm Practice
Replies: 6
Views: 128

Midterm Practice

Does anyone know if there is a worksheet for 14B midterm practice like the Dino Nuggets one for 14A? If so, what is it called?
by Racquel Fox 2I
Mon Jan 25, 2021 12:20 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook 4E.7 part b
Replies: 3
Views: 17

Textbook 4E.7 part b

Use the data in Tables 4E.2 and 4E.3 to estimate the reaction enthalpy for b) CH3CHCH2 (g) + H2O --> CH3CH(OH)CH3 (g) How do you calculate the bond enthalpy for H2O? The tables don't give it, and the only bond enthalpy they give is O-H, which I don't think you can just multiply by two because that w...
by Racquel Fox 2I
Sat Jan 23, 2021 5:03 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook 4D.21 part c
Replies: 1
Views: 13

Textbook 4D.21 part c

4D.21) c) Use standard enthalpies of formation from Appendix 2A to calculate the standard reaction enthalpy for each of the following reactions: H2S (aq) + 2KOH (aq) --> K2S (aq) + 2H2O (l) I got -38.72 kJ as the answer, but the solutions says its +15.28 kJ. I got the other parts right, so I thought...
by Racquel Fox 2I
Sat Jan 23, 2021 12:43 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook 4D.13
Replies: 1
Views: 12

Textbook 4D.13

4D.13) Barium metal is produced by the reaction of aluminum metal with barium oxide. From the standard reaction enthalpies, 2Ba(s) + O2(g) --> 2BaO (s) deltaH = -1107 kJ 2Al(s) + 3/2O2(g) --> Al2O3(s) deltaH=1676 kJ calculate the reaction enthalpy for the production of metallic barium in the reactio...
by Racquel Fox 2I
Mon Jan 18, 2021 12:44 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Textbook 6D.15 part b
Replies: 1
Views: 19

Textbook 6D.15 part b

Calculate the pH of (b) 0.055 M AlCl3(aq).

Where do you find the Ka/Kb value for this part? I can't find it in the 6C.1 and 6C.2 tables?
by Racquel Fox 2I
Sun Jan 17, 2021 7:33 pm
Forum: Student Social/Study Group
Topic: Study Strategies
Replies: 31
Views: 97

Re: Study Strategies

I struggled a lot in 14A, but found when I read over the information in the textbook for the next lecture before it occurred, I was able to get a better understanding of the material when doing the textbook problems. Also, definitely go to the UA workshops! They are so helpful and give you extra pra...
by Racquel Fox 2I
Sun Jan 17, 2021 6:47 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Sapling Week 2 #2
Replies: 4
Views: 42

Sapling Week 2 #2

At first when I did this problem, I made the assumption that you could change the 0.176-x in the denominator of the Ka equation to just 0.176 and got the answer wrong. When attempting it for the second time, I kept it as 0.176-x and got it right, but I'm a little confused on when you can assume that...
by Racquel Fox 2I
Sun Jan 17, 2021 1:14 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q > K, Q< K
Replies: 25
Views: 114

Re: Q > K, Q< K

When Q>K, the reaction shifts towards the reactants, and when Q<K, the reaction shifts toward the products. There's a tip where if you write the K before the Q, the arrow points towards the direction of the shift: K<Q, shift toward reactants; K>Q, shift toward products.
by Racquel Fox 2I
Sun Jan 17, 2021 1:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: sapling week 1/2 #2
Replies: 3
Views: 47

Re: sapling week 1/2 #2

Where exactly are you having trouble? Make sure you are setting up the ICE box correctly, finding all of the equilibrium concentrations, and then solving for K.
by Racquel Fox 2I
Fri Jan 15, 2021 1:01 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6D.5 part d
Replies: 3
Views: 60

6D.5 part d

6D.5) Calculate the pH, pOH, and percentage protonation of solute in each of the following aqueous solutions: (d) 0.0073 M codeine, given that the pKa of its conjugate acid is 8.21. I don't really know how to go about starting this problem since the formula for codeine isn't given. If anyone could t...
by Racquel Fox 2I
Sun Jan 10, 2021 5:43 pm
Forum: Student Social/Study Group
Topic: Study Habits
Replies: 96
Views: 405

Re: Study Habits

I struggled with studying for midterms for 14A, but I did much better on the final when I started learning the material before it appeared in lecture, so that lecture was more of a review for me to get a better understanding. Also, do a LOT of practice problems!
by Racquel Fox 2I
Sat Jan 09, 2021 3:53 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Impacts of Increasing Pressure
Replies: 4
Views: 13

Re: Impacts of Increasing Pressure

I'm pretty sure that even if the problem doesn't mention volume, the volume change is inferred because you can't have an increase in pressure and have everything else stay the same.
by Racquel Fox 2I
Thu Jan 07, 2021 5:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial pressure vs concentration
Replies: 6
Views: 65

Re: Partial pressure vs concentration

I'm pretty sure you would generally use the partial pressure for gases, but you are able to convert pressure to concentration and vice versa by the equation Lavelle mentioned in class: P = nRT/V where n/V = concentration
by Racquel Fox 2I
Thu Jan 07, 2021 5:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #5
Replies: 4
Views: 50

Re: Sapling #5

The way I did this problem was by looking at the reactants and products given in the equation, and then seeing which other chemical equations contained them. For this problem, the two equations used are I2 <--> 2I and N2 + 3H2 <--> 2NH3. There are a couple rules regarding this type of problem worth ...
by Racquel Fox 2I
Tue Jan 05, 2021 3:00 pm
Forum: Student Social/Study Group
Topic: Learning Sessions
Replies: 24
Views: 155

Re: Learning Sessions

I think I understood the material best when I went to 2 during a week, but it completely depends on your schedule, and if that doesn't work for you definitely try to attend at least one.
by Racquel Fox 2I
Sat Dec 12, 2020 3:12 pm
Forum: Amphoteric Compounds
Topic: Glycine Amphoteric
Replies: 3
Views: 38

Re: Glycine Amphoteric

Sana Nagori 2J wrote:I think because if oxygen donated a pair it would end up with a positive formal charge and oxygens do not want that.


Why would N want a +1 charge thought?
by Racquel Fox 2I
Sat Dec 12, 2020 2:50 pm
Forum: Amphoteric Compounds
Topic: Glycine Amphoteric
Replies: 3
Views: 38

Glycine Amphoteric

For the lewis structure of glycine, (NH2CH2COOH), you get N with a lone pair, and two O with two lone pairs. The lone pair on the N contributes to the amphoteric character, but why wouldn't the lone pairs on the O atoms? I'm not sure if that makes sense, but I'm just a little confused why the lone p...
by Racquel Fox 2I
Sat Dec 12, 2020 12:31 am
Forum: Lewis Structures
Topic: Exception to Octet rule (Cl)
Replies: 6
Views: 43

Re: Exception to Octet rule (Cl)

Cl can have an expanded octet because its in the 3rd period on the periodic table, and the 3p elements and lower can have an expanded octet. I believe for this problem Cl would be the central atom for the sake of symmetry where it could have two O on either side that are double bonded, and a lone pa...
by Racquel Fox 2I
Fri Dec 11, 2020 1:44 pm
Forum: Biological Examples
Topic: Hemoglobin Information for Final
Replies: 3
Views: 94

Re: Hemoglobin Information for Final

Kailani_Dial_3G wrote:Heme.png

This would be the octahedral shape as you can see it has the attachments above and below the heme

If you were to remove the Oxygen and the histadine that it attached to the bottom then it would be square planar


Thank you that's really helpful!
by Racquel Fox 2I
Fri Dec 11, 2020 1:19 pm
Forum: Biological Examples
Topic: Hemoglobin Information for Final
Replies: 3
Views: 94

Hemoglobin Information for Final

I was doing the Marshmallow worksheet and was confused on the answer for the expected geometry for the compound for the heme complex (Q 20). The answers say that the shape is tetrahedral or square planar, but how can it be both of those if square planar is an octahedral electron geometry? I'm not su...
by Racquel Fox 2I
Wed Dec 09, 2020 10:48 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation
Replies: 2
Views: 62

Rydberg Equation

I know the Rydberg equation on the equation sheet is v=R[1/(n1^2) - 1/(n2^2)], but in one of the review sessions yesterday the equation En=-(hR)/n^2 was brought up. Can you derive the first equation from the second one, and if we had a question on the final asking about energy levels, which equation...
by Racquel Fox 2I
Tue Dec 08, 2020 10:14 pm
Forum: Conjugate Acids & Bases
Topic: Acid Base Equilibrium
Replies: 1
Views: 18

Acid Base Equilibrium

Predict the product of the following acid-base reactions, and also predict whether the equilibrium lies to the left or to the right of the equation:
HCO3 - (aq) + F - (aq)

I got that the products would be HF and CO3 2-, but I'm a little confused on how you know where the equilibrium lies?
by Racquel Fox 2I
Tue Dec 08, 2020 8:40 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Shape of Coordination Compounds
Replies: 1
Views: 36

Shape of Coordination Compounds

Is the only way to find the shape of a coordination compound to draw out the Lewis structure, or is there another way?
by Racquel Fox 2I
Mon Dec 07, 2020 9:50 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 2
Views: 70

Cisplatin

I've seen a few problems in workshops that ask specific questions about cisplatin, and I don't fully understand them and want to go over it more. Does anyone know where in the textbook it explains?
by Racquel Fox 2I
Sun Dec 06, 2020 6:54 pm
Forum: Polyprotic Acids & Bases
Topic: Textbook 6C.19
Replies: 7
Views: 88

Re: Textbook 6C.19

I'm a little confused on the answer for part a) and part c). Part a) is comparing HF and HCl and part c) is comparing HBrO2 and HClO2. Why would HCl be stronger than HF, and HClO2 stronger than HBrO2? What is the periodic trend going on? Remember in the last lecture where Dr. Lavelle said that the ...
by Racquel Fox 2I
Sun Dec 06, 2020 6:20 pm
Forum: Polyprotic Acids & Bases
Topic: Textbook 6C.19
Replies: 7
Views: 88

Textbook 6C.19

I'm a little confused on the answer for part a) and part c). Part a) is comparing HF and HCl and part c) is comparing HBrO2 and HClO2. Why would HCl be stronger than HF, and HClO2 stronger than HBrO2? What is the periodic trend going on?
by Racquel Fox 2I
Sun Dec 06, 2020 12:45 pm
Forum: Student Social/Study Group
Topic: Studying for Final Exam
Replies: 57
Views: 452

Re: Studying for Final Exam

I'm going to go over textbook problems on the unit outlines, starting with newer material and working backward. I'm also definitely going to review sessions with UAs this week. If it helps you, try and make a schedule to plan out how you will be studying each day for the final. It makes your studyin...
by Racquel Fox 2I
Sun Dec 06, 2020 12:43 pm
Forum: Administrative Questions and Class Announcements
Topic: Partial Credit on the Final
Replies: 6
Views: 95

Partial Credit on the Final

Does anyone know if any of the questions on the final exam will offer partial credit? Or will it be more like the second midterm where no partial credit was offered?
by Racquel Fox 2I
Thu Dec 03, 2020 10:24 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelates and Polydentates
Replies: 2
Views: 21

Chelates and Polydentates

Are all polydentates automatically considered chelates?
by Racquel Fox 2I
Thu Dec 03, 2020 10:41 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Sapling Homework #5
Replies: 2
Views: 53

Sapling Homework #5

I'm a little confused on how to go about finding coordination numbers for this question. At first I thought it had
something to do with the oxidation state, so I don't really know how to start if someone could
let me know a good starting point.
by Racquel Fox 2I
Wed Dec 02, 2020 3:47 pm
Forum: Naming
Topic: Oxidation State
Replies: 4
Views: 51

Oxidation State

Are oxidation states just the charge on the atoms?
by Racquel Fox 2I
Sun Nov 29, 2020 3:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent
Replies: 9
Views: 92

Re: Bent

Yeah I'm pretty sure it is.
by Racquel Fox 2I
Sat Nov 28, 2020 2:26 pm
Forum: Student Social/Study Group
Topic: Midterm Exam Questions
Replies: 16
Views: 204

Re: Midterm Exam Questions

Definitely email your TA to schedule a meeting to go over your midterm. I just went over my midterm with my TA and it clarified a lot for me.
by Racquel Fox 2I
Sat Nov 28, 2020 2:25 pm
Forum: Student Social/Study Group
Topic: Final Study
Replies: 32
Views: 265

Re: Final Study

I would try and do more of the textbook problems, and definitely find some of the worksheets from past workshops. If you search chemistry community, you can usually find some :)
by Racquel Fox 2I
Sat Nov 28, 2020 2:21 pm
Forum: Student Social/Study Group
Topic: Studying From Home
Replies: 91
Views: 647

Re: Studying From Home

I feel the same way, I always went to the library and used to never be able to study at home. I just try to switch up my location in my house a bit so I'm never stuck in one place for too long. I like to listen to music while I study because it helps me get into more of a rhythm while studying. I al...
by Racquel Fox 2I
Thu Nov 26, 2020 3:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Chart
Replies: 18
Views: 138

VSEPR Chart

Does anyone know if we will get a VSEPR chart for the final, or do we have to memorize all of the molecular shapes?
by Racquel Fox 2I
Sun Nov 22, 2020 10:31 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: Polarizablity
Replies: 10
Views: 93

Re: Polarizablity

Polarizability is the tendency of an anion to get distorted by a cation and increases when the size of the anion increases.
by Racquel Fox 2I
Sun Nov 22, 2020 4:49 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Plausible Formal Charges
Replies: 6
Views: 47

Re: Plausible Formal Charges

The most stable Lewis structure is the structure with the lowest amount of charge, if not a charge of zero.
by Racquel Fox 2I
Wed Nov 18, 2020 10:17 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: d vs s orbitals
Replies: 7
Views: 152

Re: d vs s orbitals

Jacquelyn Challis 1H wrote:Just to clarify, when writing electron configurations, would you write 3d or 4s first? I've seen it done both ways and I'm getting confused.


In order to fill them in the right order, you can write 4s first, but proper electron configuration is to put it back to 3d, 4s.
by Racquel Fox 2I
Tue Nov 17, 2020 3:39 pm
Forum: Quantum Numbers and The H-Atom
Topic: Cr+ Ground State Electron Configuration
Replies: 2
Views: 38

Cr+ Ground State Electron Configuration

Write the ground-state electron configuration for Cr+ and give the first two quantum numbers for the last electron.
Answer: Cr: [Ar]4s13d5, Cr+: [Ar] 3d5

Why would the 4s orbital only have 1 electron?
by Racquel Fox 2I
Tue Nov 17, 2020 12:29 pm
Forum: Quantum Numbers and The H-Atom
Topic: Quantum Number Practice
Replies: 3
Views: 89

Quantum Number Practice

Does anyone have any good extra quantum number practice? I did all of the questions in the textbook and the sapling homework but I just want to make sure I'm really prepared for MT2.
by Racquel Fox 2I
Sun Nov 15, 2020 4:43 pm
Forum: Octet Exceptions
Topic: Textbook 2C.1
Replies: 5
Views: 55

Re: Textbook 2C.1

SebastianCastellanos2L wrote:I ran into the same problem and I also think that the answer key in the online textbook is likely mistaken. I have noticed that its missing answers for certain questions and the explanation from the physical one makes the most sense.


Thank you! I'm glad I'm not the only one haha
by Racquel Fox 2I
Sat Nov 14, 2020 1:42 pm
Forum: Octet Exceptions
Topic: Textbook 2C.1
Replies: 5
Views: 55

Textbook 2C.1

Which of the following species are radicals? a) NO2-; b) CH3; c) OH; d) CH2O I'm a little confused on part A of 2C.1. I counted the number of valence electrons, and with the added electron from the negative charge, I got 18 ve-, but in the answer key that is one of the radicals. What am I doing wron...
by Racquel Fox 2I
Sat Nov 14, 2020 1:22 pm
Forum: Student Social/Study Group
Topic: Midterm 2
Replies: 22
Views: 141

Re: Midterm 2

I'm going to focus more on the textbook problems. I think I'm going to do all of the odd questions in the sections, and then when I have a good grip on them I'm going to go back and do the evens. Also, I'm going to spend more time really understanding the conceptual ideas because that's where I had ...
by Racquel Fox 2I
Sat Nov 14, 2020 1:20 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Number of Resonance Structures
Replies: 7
Views: 129

Re: Number of Resonance Structures

I know that resonance structures are any molecule with 2 or more Lewis dot structures, but I'm pretty sure we wouldn't get a really hard, time-extensive one on the midterm, so I wouldn't worry too much about that :)
by Racquel Fox 2I
Wed Nov 11, 2020 2:55 pm
Forum: Ionic & Covalent Bonds
Topic: Textbook: 2a.3
Replies: 2
Views: 42

Textbook: 2a.3

I just wanted to check and see if I was setting up electron configurations right for 2a.3. 2a.3)a) S^2- : 1s^2 2s^2 2p^6 3s^2 3p^6 or Ar 2a.3)b) As^3+ : 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 or Ar 3d^10 4s^2 2a.3)d) Ge^2+ : 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 or Ar 3d^10 4s^2 Also, I'm slightly confus...
by Racquel Fox 2I
Fri Nov 06, 2020 8:15 pm
Forum: Lewis Structures
Topic: Electron Configuration; Aufbau Principle
Replies: 5
Views: 60

Re: Electron Configuration; Aufbau Principle

Thank you so much! I was having a lot of trouble understanding it so it's really nice to have that help :)
by Racquel Fox 2I
Fri Nov 06, 2020 8:13 pm
Forum: Properties of Light
Topic: Photoelectric Effect
Replies: 14
Views: 199

Re: Photoelectric Effect

Yes, I'm pretty sure that the excess energy is the same as the kinetic energy because the kinetic energy is the excess energy that is produced when the energy of the photon is greater than the work function.
by Racquel Fox 2I
Fri Nov 06, 2020 8:07 pm
Forum: Student Social/Study Group
Topic: Blind sided by Midterm 1 memorization questions, How to study for memorization questions
Replies: 11
Views: 118

Re: Blind sided by Midterm 1 memorization questions, How to study for memorization questions

I feel the same; I feel like I studied really hard to try and get all of the calculations down, but skimmed over the conceptual parts and thought I would be able to reason them out. I think that the best thing we can do going forward is put a little more time into truly understanding the conceptual ...
by Racquel Fox 2I
Fri Nov 06, 2020 8:03 pm
Forum: Ionic & Covalent Bonds
Topic: Formal Charge Equation
Replies: 10
Views: 58

Formal Charge Equation

I know that the equation for the formal charge for Lewis Dot Structure is FC = # valence electrons - the number of dots and lines, but I'm getting a little confused on the concept behind the bond lines. I know that they are bonded electrons, but why would one bond line count as one when it is two el...
by Racquel Fox 2I
Wed Oct 28, 2020 1:01 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Post-Module Assessment #28
Replies: 1
Views: 43

Atomic Spectra Post-Module Assessment #28

The meter was defined in 1963 as 1,650,763.73 wavelengths of radiation emitted by krypton-86 (it has since been redefined). What is the wavelength of this krypton-86 radiation? To what region of the electromagnetic spectrum does this wavelength correspond (i.e. infrared, ultraviolet, x-ray, etc.)? W...
by Racquel Fox 2I
Tue Oct 27, 2020 10:26 pm
Forum: Einstein Equation
Topic: Work Function and Energy of Photons
Replies: 4
Views: 69

Work Function and Energy of Photons

In some practice problems I've been doing I noticed that E=hv is equal to the work function. How do you know when you are supposed to set them equal to each other?
by Racquel Fox 2I
Tue Oct 27, 2020 3:30 pm
Forum: Properties of Light
Topic: Energy Equations Confusion
Replies: 6
Views: 66

Re: Energy Equations Confusion

In order to solve this you need to know the work function of the substance the incident light is ejecting the electron from. Once you know this you can use the photoelectric equation (kinetic energy of electron) = (energy of photon) - (work function). Plug in the kinetic energy of the electron and ...
by Racquel Fox 2I
Tue Oct 27, 2020 3:27 pm
Forum: Properties of Light
Topic: Energy Equations Confusion
Replies: 6
Views: 66

Re: Energy Equations Confusion

Minh-Thy Vo 3E wrote:To find the energy you would use Ek=1/2mv^2 because it is asking for kinetic energy.
For the wavelength you would use the de Broglie equation wavelength= h/p using the mass of an electron and the velocity given.


I thought that the kinetic energy was given? Am I wrong about that?
by Racquel Fox 2I
Tue Oct 27, 2020 3:23 pm
Forum: Properties of Light
Topic: Energy Equations Confusion
Replies: 6
Views: 66

Energy Equations Confusion

A shorter wavelength light source is used resulting in ejected electrons with a kinetic energy of 4.200 * 10^-19 J
What is the energy of the incident light?
What is the wavelength of this incident light?

I'm a little confused on how to start this equation if anyone could offer some insight.
by Racquel Fox 2I
Mon Oct 26, 2020 10:39 pm
Forum: Properties of Light
Topic: 1B. 5 Textbook problem
Replies: 1
Views: 34

Re: 1B. 5 Textbook problem

1 keV uses the prefix "kilo", so you would need to convert the keV to eV by multiplying by 10^3 eV and then converting to J.
by Racquel Fox 2I
Mon Oct 26, 2020 10:37 pm
Forum: Properties of Electrons
Topic: Sapling Homework #14
Replies: 5
Views: 79

Re: Sapling Homework #14

I'm pretty sure n2 = 7, and with that you would get the v = R((1/n1^2) - (1/n2^2)) to be 3.29*10^15 x ((1/4)-(1/49)). Why does n2=7? Sorry, I just looked back at your post and realized you said your n2=6. I'm not sure if we have different questions, but my #14 on Sapling states: Calculate the wavel...
by Racquel Fox 2I
Mon Oct 26, 2020 10:28 pm
Forum: Administrative Questions and Class Announcements
Topic: Locked out of textbook
Replies: 1
Views: 34

Re: Locked out of textbook

I would email your TA to figure it out, especially if you've already redeemed your access code.
by Racquel Fox 2I
Mon Oct 26, 2020 10:26 pm
Forum: General Science Questions
Topic: help with work function hw question
Replies: 2
Views: 56

Re: help with work function hw question

For the first part, I think you would use the Ek = hv - phi equation and solve for phi. So you would basically get
phi = hv - Ek --> (6.626*10^-34)(1.15 s^-1) - (3.80*10^-19 J)
by Racquel Fox 2I
Mon Oct 26, 2020 10:19 pm
Forum: Empirical & Molecular Formulas
Topic: Limiting Reactant Calculations Module #22
Replies: 2
Views: 56

Limiting Reactant Calculations Module #22

According to the following equation, 0.750 g of C6H9Cl3 is mixed with 1.000 kg of AgNO3 in a flask of water. A white solid, AgCl, completely precipitates out. What is the mass of AgCl produced? C6H9Cl3 + 3AgNO3 ---> AgCl + C6H9(NO3)3. Molar Mass: C6H9Cl3 (187.50 g/mol), 3AgNO3 (169.88 g/mol), AgCl (...
by Racquel Fox 2I
Mon Oct 26, 2020 10:08 pm
Forum: Properties of Light
Topic: Tips for knowing what equation to use?
Replies: 5
Views: 75

Re: Tips for knowing what equation to use?

I think you would use De Broglie's equation anytime there is noticeable mass, so if the question is asking about an electron or something along those lines. If the question is asking about a photon, because they are massless, you would use the E=hv equation.

Go to advanced search