## Search found 101 matches

Mon Mar 09, 2020 12:45 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Replies: 3
Views: 69

I think it's always best to ensure your answer makes sense for the reaction as a method to check too! For example, if we got an order that was an extremely high numbe, something most likely is off
Mon Mar 09, 2020 12:42 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: 7.9
Replies: 2
Views: 30

### Re: 7.9

I believe the pseudo first order equation is especially applicable in the lab and helpful in solving for undetermined values regarding a specific reaction
Mon Mar 09, 2020 12:40 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Replies: 73
Views: 3815

I think going over some of the questions other students have asked on Chem Community is helpful in ensuring you understand every aspect of the topics and maybe help pick up on concepts you missed!
Mon Mar 09, 2020 12:37 pm
Forum: General Rate Laws
Topic: Formula for Individual Reactant Order
Replies: 1
Views: 25

### Formula for Individual Reactant Order

Is there a specific formula to use to solve for the individual reactant orders when given values in a table such as in 7A.17?
Mon Mar 09, 2020 12:33 pm
Forum: *Enzyme Kinetics
Topic: Catalyst Practice
Replies: 3
Views: 63

### Catalyst Practice

Does anyone know of a good video or practice problems relating to catalysts?
Tue Mar 03, 2020 6:49 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6N.1.b
Replies: 1
Views: 27

### Re: 6N.1.b

I noticed this too... I believe its a solutions manual error
Tue Mar 03, 2020 2:07 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: lnQ vs logQ
Replies: 5
Views: 59

### Re: lnQ vs logQ

The logQ is especially helpful if calculating/given the pH!
Tue Mar 03, 2020 2:06 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Reducing final equation to get n?
Replies: 2
Views: 41

### Re: Reducing final equation to get n?

I think in that problem, the question didn't require you to use the n value in further steps so it did not matter if you simplified the final equation
Tue Mar 03, 2020 2:01 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6N 9: anode v cathode
Replies: 2
Views: 39

### Re: 6N 9: anode v cathode

I believe if you treated it as the cathode the Ecell would be negative (which it tells you its a positive 0.061)
Tue Mar 03, 2020 1:45 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Understanding SHE
Replies: 2
Views: 46

### Understanding SHE

Hi! I understand that standard cell potentials are based upon references to the SHE model but could some one further explain what exactly the SHE entails?
Mon Feb 24, 2020 10:33 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst
Replies: 7
Views: 70

### Re: Nernst

When exactly is the cell potential considered at standard conditions?
Mon Feb 24, 2020 10:24 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 7
Views: 86

### Re: Cell Diagrams

I am confused on this as well, when do we need to introduce Pt into the system?
Mon Feb 24, 2020 10:14 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Mon Feb 24, 2020 10:14 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Mon Feb 24, 2020 10:13 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Mon Feb 17, 2020 9:19 am
Forum: Balancing Redox Reactions
Replies: 2
Views: 42

Hi! For anyone who learns well off of video tutorials Khan Academy has some great ones for this section! https://www.khanacademy.org/science/che ... -reduction
Mon Feb 17, 2020 9:18 am
Forum: Balancing Redox Reactions
Topic: Possibly helpful: LEO the lion goes GER
Replies: 2
Views: 119

### Re: Possibly helpful: LEO the lion goes GER

This is super helpful thank you!
Mon Feb 17, 2020 9:16 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: When to use the different equations
Replies: 5
Views: 78

### Re: When to use the different equations

I'm a bit confused about this as well because that delta G equation can also be applied when K is used (the equation is at equilibrium)
Mon Feb 17, 2020 9:11 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: importance of -RTlnk
Replies: 7
Views: 67

### Re: importance of -RTlnk

"K is the constant of a certain reaction when it is in equilibrium, while Q is the quotient of activities of products and reactants at any stage of a reaction." Therefore, this equation depicts delta G at equilibrium.
Mon Feb 17, 2020 9:10 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: sign of delta G
Replies: 9
Views: 127

### Re: sign of delta G

When delta G is negative, the reaction is spontaneous and will shift towards the products. When it is positive, the reverse reaction is spontaneous and will shift towards the reactants.
Mon Feb 17, 2020 9:08 am
Forum: Administrative Questions and Class Announcements
Topic: Step Up Sessions
Replies: 66
Views: 4161

### Re: Step Up Sessions

Hi! Will there still be UA review sessions today despite the holiday?
Mon Feb 10, 2020 10:04 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Extra Practice
Replies: 4
Views: 77

### Extra Practice

Hi! Does anyone know where to possible find more practice problems regarding applying Le Chatelier's Principle?
Mon Feb 10, 2020 10:03 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 4F.17
Replies: 1
Views: 43

### Re: 4F.17

I believe you assume you are using one mole in the reaction
Mon Feb 10, 2020 10:01 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: spontaneity
Replies: 18
Views: 150

### Re: spontaneity

What is the significance of whether or not a reaction is spontaneous? How do we apply this is real-world situations?
Mon Feb 10, 2020 9:59 am
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: standard entropy meaning
Replies: 3
Views: 18

### Re: standard entropy meaning

The naught above the S indicates standard state.
Mon Feb 10, 2020 9:55 am
Forum: Administrative Questions and Class Announcements
Topic: Step Up Sessions
Replies: 66
Views: 4161

### Re: Step Up Sessions

Hi does anyone know if Lyndon's workshop is still happening tonight?
Mon Feb 03, 2020 7:17 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: q vs H
Replies: 9
Views: 59

### Re: q vs H

Are deltaH and q interchangeable?
Mon Feb 03, 2020 7:15 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Reversible/ Irreversible Expansion
Replies: 3
Views: 36

### Re: Reversible/ Irreversible Expansion

Would the problems always specify whether it's reversible or irreversible? If not, how can we assume?
Mon Feb 03, 2020 7:13 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4A.9
Replies: 2
Views: 40

### Re: 4A.9

Also it says that no heat is lost to surroundings so we can assume that heat moves out of the copper and into the water, eventually making their temperatures equal to one another.
Mon Feb 03, 2020 7:10 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4B.5
Replies: 3
Views: 43

### Re: 4B.5

In this case would it be necessary to convert the pressure from Torr to atm before plugging it into the equation?
Mon Feb 03, 2020 7:07 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sig figs and calorimetry example
Replies: 2
Views: 25

### Re: Sig figs and calorimetry example

I believe in this example he was more emphasizing the process of solving those type of problems and wanted to show us accurate calculations (before sig fig rounding)
Mon Jan 27, 2020 2:55 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Mon Jan 27, 2020 2:54 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Mon Jan 27, 2020 2:51 pm
Forum: Phase Changes & Related Calculations
Topic: Chem 14A Final Pickup
Replies: 8
Views: 82

### Re: Chem 14A Final Pickup

Does anyone know where and when we can pick them up?
Mon Jan 27, 2020 2:49 pm
Forum: Phase Changes & Related Calculations
Topic: ∆H
Replies: 17
Views: 131

### Re: ∆H

There are some instances where you can assume without the actual value such as when you break a bond (endothermic as energy is required to break the bond)
Mon Jan 27, 2020 2:39 pm
Forum: Phase Changes & Related Calculations
Topic: phase changes
Replies: 5
Views: 45

### Re: phase changes

I am a bit confused on this topic. Could someone please use an example of how phase changes are taken into account?
Mon Jan 20, 2020 4:37 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Mon Jan 20, 2020 4:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Salt Solutions
Replies: 3
Views: 44

### Re: Salt Solutions

Hi! I found this video to be very useful on this topic. https://www.khanacademy.org/science/che ... -solutions
Mon Jan 20, 2020 4:30 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 2
Views: 26

### Re: Le Chatelier's Principle

Also, if the moles of gas on either side of the reaction (and therefore space taken up in the volume) are equal than a change in pressure has no effect
Mon Jan 20, 2020 4:28 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Summary of Le Chatelier
Replies: 5
Views: 40

### Re: Summary of Le Chatelier

This is a great summary of the concept! https://www.khanacademy.org/science/che ... -principle
Mon Jan 20, 2020 4:27 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic Reactions
Replies: 4
Views: 40

### Re: Endothermic Reactions

However, remember that if the reaction is a exothermic reaction, adding heat will result in the formation of reactants
Mon Jan 13, 2020 2:12 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 5I.13
Replies: 3
Views: 93

### Re: 5I.13

Hi this is a pretty involved question and I was confused at first as well but the step by step solution in the Solutions Manual was really helpful!
Mon Jan 13, 2020 2:09 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Practice Problems
Replies: 4
Views: 106

### Re: Practice Problems

I found this worksheet online too which can give you a couple more practice problems on the topic. http://mmsphyschem.com/lechatP.pdf
Mon Jan 13, 2020 2:08 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Increase pressure by half the volume
Replies: 3
Views: 24

### Re: Increase pressure by half the volume

This is true however remember that the actual equilibrium ratio remains the same. Only temperature can change K. :)
Mon Jan 13, 2020 2:07 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: "Quick way" part in Lecture
Replies: 7
Views: 78

### Re: "Quick way" part in Lecture

I am also a bit confused on this topic. Can someone please explain the difference between the quick way and the actual reasoning to solve these types of problems? Thanks
Mon Jan 13, 2020 2:05 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Textbook question 5J.11
Replies: 3
Views: 29

### Re: Textbook question 5J.11

Yes! Because it involves the breaking of the bond between the two X molecules to form two separated X molecules we know that energy aka heat had to be put into the reaction to overcome the bond energy. Therefore it is endothermic.
Mon Jan 06, 2020 2:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Determining Equilibrium Reaction Direction
Replies: 4
Views: 64

### Re: Determining Equilibrium Reaction Direction

So would anything between k > 10^3 and k > 1 be only slight favoring?
Mon Jan 06, 2020 2:34 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Mon Jan 06, 2020 2:33 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Mon Jan 06, 2020 2:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Self Test 5G.3A
Replies: 4
Views: 50

### Self Test 5G.3A

Write the equilibrium constant fir the reaction 2 AgNO3 (aq) + 2NaOH (aq)-----> Ag2O (s) + 2NaNO3 (aq) + H2O (l)

I'm a bit confused as to how to take the net ionic equation into account. Thanks!
Mon Jan 06, 2020 2:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Question 5G
Replies: 3
Views: 344

### Re: Question 5G

If you are referring to 5G.1 part c, they aren't asking you to calculate the partial pressure but rather want you to state that the statement is false. Equilibrium reactions are affected by the presence of both products and reactants.
Mon Dec 02, 2019 12:14 pm
Forum: Calculating the pH of Salt Solutions
Topic: 6D.11 c and d
Replies: 1
Views: 33

### Re: 6D.11 c and d

I believe that book sometimes does it differently and keeps the halogens in the equations either way but I was confused about this too.
Mon Dec 02, 2019 12:12 pm
Forum: Polyprotic Acids & Bases
Topic: Section 6E.1
Replies: 2
Views: 54

### Re: Section 6E.1

I believe so and I think he wanted us to heavily focus on the description box 6E.1 in particular
Mon Dec 02, 2019 12:10 pm
Forum: Polyprotic Acids & Bases
Topic: Chelates Visual
Replies: 2
Views: 58

### Chelates Visual

Does anyone know of any helpful videos or images to help me picture how chelates function? Thanks!
Mon Dec 02, 2019 12:08 pm
Forum: Amphoteric Compounds
Topic: amphiprotic and amphoteric
Replies: 9
Views: 132

### Re: amphiprotic and amphoteric

An analogy that helped me was that of a rectangle and a square.... a square is always a rectangle but a rectangle isn't always a square. The same goes for these terms as amphiprotic is always amphoteric but amphoteric molecules are not always amphiprotic
Mon Dec 02, 2019 11:58 am
Forum: Bronsted Acids & Bases
Topic: 6.5
Replies: 1
Views: 50

### 6.5

How can you tell which is the base and which is the acid in the formula:

H2O2 + SO3 -----> H2SO5

I tried drawing lewis structures but still don't quite understand. Thanks!
Mon Nov 25, 2019 9:25 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: coordination sphere
Replies: 3
Views: 85

### Re: coordination sphere

I understand the concept of a coordination sphere but am a bit unsure of how to identify a ligand versus other molecules that would not be included. Can someone explain this is detail please? Thanks!
Mon Nov 25, 2019 9:22 am
Forum: Naming
Topic: Naming Help
Replies: 1
Views: 44

### Naming Help

Has anyone seen any helpful videos to explain/help memorize how to name compounds? Thanks!
Mon Nov 25, 2019 9:22 am
Forum: Naming
Topic: Coordination shape
Replies: 3
Views: 46

### Re: Coordination shape

I believe you would need more information to identify exactly which shape it is such as hybridization or specific numbers of lone pairs/bonding pairs
Mon Nov 25, 2019 9:20 am
Forum: Industrial Examples
Topic: Favorite Industrial Example
Replies: 3
Views: 490

### Re: Favorite Industrial Example

As someone stated previously, I think bismuth subsalicylate, or Pepto-Bismol, is an example of an industrial coordination compound.
Mon Nov 25, 2019 9:19 am
Forum: Biological Examples
Replies: 2
Views: 96

Here's what I gathered...
- it is an example of a cage-like molecule
- it is square planar
- Fe is bound to the porphyrin ligand to form a heme complex
- the heme complex plus a protein creates myoglobin (Fe binds to 1 O2)
- it plays a role in the transport of O2 in the muscle cells
Wed Nov 20, 2019 9:13 am
Forum: Determining Molecular Shape (VSEPR)
Topic: HW 2F:21a
Replies: 2
Views: 48

### Re: HW 2F:21a

the shape will be trigonal planar around each C atom
Wed Nov 20, 2019 9:12 am
Forum: Determining Molecular Shape (VSEPR)
Topic: 2.45 Homework Question
Replies: 1
Views: 46

### Re: 2.45 Homework Question

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Wed Nov 20, 2019 9:09 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Resonance and Rotation
Replies: 1
Views: 40

### Resonance and Rotation

If a molecule has resonance (some double bonds and some single bonds) and therefore a few pi bonds can any of the atoms rotate?
Wed Nov 20, 2019 9:04 am
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.13 part a
Replies: 3
Views: 46

### Re: 2E.13 part a

If a molecule has two bond pairs and 3 lone pairs (AX2E3) it is linear in shape and therefore has a bond angle of 180 degrees.
Wed Nov 20, 2019 9:03 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs for AX4E
Replies: 3
Views: 47

### Re: Lone Pairs for AX4E

The lone pairs are placed based on repulsion strengths:

lone pr-lone pr>lone pr-bond pr>bond pr-bond pr

Therefore, by placing the lone pair on the equatorial plane, it allows for repulsion strengths to play out
Tue Nov 12, 2019 10:00 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Tue Nov 12, 2019 9:58 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Simpler Terms
Replies: 4
Views: 394

### Re: Simpler Terms

I found this Khan Academy video to be really helpful on explaining this topic! https://www.khanacademy.org/science/che ... amagnetism
Tue Nov 12, 2019 9:57 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: bond order
Replies: 4
Views: 303

### Re: bond order

Hi! I found this link to be very helpful in explaining the topic: https://chem.libretexts.org/Bookshelves ... _Chemistry)/Chemical_Bonding/Fundamentals_of_Chemical_Bonding/Bond_Order_and_Lengths
Tue Nov 12, 2019 9:52 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Memorization Tips
Replies: 3
Views: 59

### Re: Memorization Tips

Not sure where this quizlet is from but it was really helpful for me to memorize! https://quizlet.com/291777131/vsepr-shapes-flash-cards/
Tue Nov 12, 2019 9:50 am
Forum: Hybridization
Topic: Hybridization Models
Replies: 4
Views: 105

### Re: Hybridization Models

Wed Nov 06, 2019 9:37 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 54
Views: 5902

### Re: Accessing the E-textbook[ENDORSED]

If anyone has any issues opening the Sapling after purchasing it from the UCLA bookstore I called the company and it was really helpful. I just had to send a picture of my receipt and etext code and they registered my account for the class.
Wed Nov 06, 2019 9:34 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Wed Nov 06, 2019 9:30 pm
Forum: Bond Lengths & Energies
Topic: Test 2 Topics
Replies: 40
Views: 837

### Test 2 Topics

Does anyone know if test 2 is cumulative or just the topics covered from the midterm to the test? Thanks!
Wed Nov 06, 2019 9:28 pm
Forum: Bond Lengths & Energies
Topic: Midterm
Replies: 9
Views: 142

### Re: Midterm

In class he suggested about a week but given it's all free response it may take longer
Wed Nov 06, 2019 9:26 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407926

### Re: Post All Chemistry Jokes Here

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Mon Oct 28, 2019 9:36 am
Forum: Quantum Numbers and The H-Atom
Topic: H atom
Replies: 3
Views: 60

### Re: H atom

I think it also has to do with that H is the most common element. It has several uses and forms cations very easily.
Mon Oct 28, 2019 9:33 am
Forum: Quantum Numbers and The H-Atom
Topic: 1D.17
Replies: 3
Views: 63

### Re: 1D.17

-1, 0, 1

-2, -1, 0, 1, 2

-1, 0, 1

-3, -2, -1, 0, 1, 2, 3
Mon Oct 28, 2019 9:29 am
Forum: Properties of Light
Topic: 1.31
Replies: 4
Views: 81

### Re: 1.31

Mon Oct 28, 2019 9:26 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E.25
Replies: 1
Views: 41

### 1E.25

Give the notation for the valence shell configuration (including the outermost d-electrons) of (a) the alkali metals; (b) Group 15 elements (c) Group 5 transition metals (d) the "coinage" metals (Cu, Ag, Au).
Mon Oct 28, 2019 9:21 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E.15
Replies: 2
Views: 46

### Re: 1E.15

I was confused about this too. I thought we were supposed to switch the 4s and 3d orbitals when writing out the configuration. Why is it 3d then 4s in the book? Must the 3d be filled to switch back to before the 4s? Thanks.
Mon Oct 21, 2019 10:48 pm
Forum: Trends in The Periodic Table
Topic: Metals, Nonmetals, Metalloids
Replies: 5
Views: 82

### Metals, Nonmetals, Metalloids

Hi, does anyone know if we must memorize which elements are metals, nonmetals, and metalloids or will it be indicated on the periodic table given to us? If so, are there any tips to memorizing which is which? Thanks!
Mon Oct 21, 2019 10:46 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E.25
Replies: 3
Views: 50

### 1E.25

Give the notation for the valence-shell configuration (including the outermost d-electrons) of (a) the alkali metals (b) Group 15 elements (c) Group 5 transition metals (d) the "coinage" metals (Cu, Ag, Au)
Mon Oct 21, 2019 10:44 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E.23
Replies: 2
Views: 43

### 1E.23

The elements Ga, Ge, As, Se, and Br lie in the same period in the periodic table. Write the electron configuration expected from the ground-state atoms of these elements and predict how many unpaired electrons, if any, each atom has.
Mon Oct 21, 2019 8:35 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 4s before 3d
Replies: 4
Views: 42

### Re: 4s before 3d

Hi here's a diagram of Aufbau's Principle, hope this helps clarify!
Mon Oct 21, 2019 8:30 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity Trends
Replies: 5
Views: 64

### Re: Electron Affinity Trends

Electron affinity decreases down the groups and increases across the periods because the electrons added are closer to the nucleus creating a stronger attraction and tighter hold.
Tue Oct 15, 2019 7:12 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: *Lowest possible energy?
Replies: 2
Views: 46

### Re: *Lowest possible energy?

Because the momentum and position are uncertain, the energy may be uncertain as well. Sometimes, the window of uncertainty is given and you could use the lowest value in this region to calculate the approximate lowest energy level.
Tue Oct 15, 2019 7:08 pm
Forum: Properties of Electrons
Replies: 3
Views: 56

### Re: Question about diffraction patterns

I hope this image helps clarify as well!
Tue Oct 15, 2019 7:06 pm
Forum: Properties of Light
Topic: What units do we need to use for the Rydberg constant?
Replies: 2
Views: 26

### Re: What units do we need to use for the Rydberg constant?

Both of these Rydberg constants are equal and vary just because of their units.

for E=-hR/n^2.... 3.28984 * 10^15 Hz should be used and that is what is given on the formula sheet
Tue Oct 15, 2019 7:00 pm
Forum: Photoelectric Effect
Topic: Wavelength Emitted
Replies: 4
Views: 63

### Wavelength Emitted

Will there always be a positive wavelength of light emitted with e- transitions no matter if it's moving up or down energy levels?
Tue Oct 15, 2019 5:24 pm
Forum: Photoelectric Effect
Topic: Module Question
Replies: 2
Views: 55

### Module Question

In 1.0s, a 60 W bulb emits 11 J of energy in the form of infrared radiation (heat) of wavelength 1850 nm. What is the energy per photon of light emitted? How many photons of infrared radiation does the lamp generate in1.0s?
Sat Oct 12, 2019 3:01 pm
Forum: Properties of Light
Topic: What exactly is diffraction?
Replies: 3
Views: 47

### Re: What exactly is diffraction?

Hi! I was a bit confused about this topic as well and found this video to be really clear! Hope this helps. https://www.youtube.com/watch?v=1bHipDSHVG4
Sat Oct 12, 2019 2:58 pm
Forum: Properties of Light
Topic: Constructive & Destructive
Replies: 4
Views: 50

### Re: Constructive & Destructive

Yes this is possible. However, they would have to have the exact same wavelength and frequency.
Sat Oct 12, 2019 12:55 pm
Forum: Properties of Light
Topic: Quanta vs Photon
Replies: 4
Views: 52

### Re: Quanta vs Photon

Quantized objects have a discrete numerical value. For example, an electron cannot jump energy levels without having exactly the amount of energy needed to move (no more no less). Because there is no halfway point, it is quantized.
Sat Oct 12, 2019 12:43 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect diagram
Replies: 3
Views: 81

### Re: Photoelectric Effect diagram

The information the detector picks up tells us about the energy of the electron (if they are emitted) and therefore can reveal important traits of the metal and/or light source.
Fri Oct 11, 2019 7:45 pm
Forum: Photoelectric Effect
Topic: Module Post Assessment 33
Replies: 1
Views: 33

### Module Post Assessment 33

Molybdenum metal must absorb radiation with a minimum frequency of 1.09 x 10^15 s^-1 before it can emit an electron from its surface. Answer the following two questions. A. What is the minimum energy needed to produce this effect? B. If molybdenum is irradiated with 194 nm light, what is the maximum...
Sat Sep 28, 2019 5:57 pm
Forum: Molarity, Solutions, Dilutions
Topic: G.13
Replies: 3
Views: 51

### Re: G.13

Hi! I was confused about this at first as well but my TA explained that since you are looking for the specific number of moles of nitrogen atoms each plant will receive, you need to relate the final mole amount to the amount of N moles in the original compound. Since the compound NH4NO3 has 2 nitrog...
Sat Sep 28, 2019 3:42 pm
Forum: Limiting Reactant Calculations
Topic: Homework Problem M.7 (b)
Replies: 2
Views: 69

### Homework Problem M.7 (b)

Solid boron can be extracted from soli boron oxide by reaction with magnesium metal at a high temperature. A second product is solid magnesium oxide. (b) What mass of boron can be produced when 1.25kg or boron oxide is heated with 125kg of magnesium? I converted the kg to g and then solved for the m...
Sat Sep 28, 2019 11:25 am
Forum: SI Units, Unit Conversions
Topic: Nomenclature
Replies: 4
Views: 201

### Nomenclature

Hi! I wasn't sure which topic to place this under and figured this was closest to general chemistry basics.... does anyone have any tips on help with nomenclature? I do not have a strong background in chemistry and am looking for some help with understanding the compound names etc. Thanks!
Sat Sep 28, 2019 10:57 am
Forum: Molarity, Solutions, Dilutions
Topic: Homework Problem G.21 [ENDORSED]
Replies: 2
Views: 84

### Homework Problem G.21[ENDORSED]

A solution is prepared by dissolving 0.500g of KCl, 0.500g of K2S, and 0.500g of K3PO4 in 500mL of water. What is the concentration in the final solution of (a) potassium ions; (b) sulfide ions? Would it be appropriate to group the compounds and their masses together at the beginning of the problem ...