Search found 115 matches

by Jessica Li 4F
Fri Oct 18, 2019 3:24 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: d orbitals
Replies: 1
Views: 34

d orbitals

I know that the p orbitals can be written as px, py, and pz, but what about the d orbitals?
Also, for tests, will we have to be specific and write out the subscripts, or can we just write, for example in carbon, 1s22s22p2 instead of 1s2 2s2 2px?
by Jessica Li 4F
Fri Oct 18, 2019 3:13 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 4s and 3d electron configurations
Replies: 1
Views: 43

4s and 3d electron configurations

In lecture today, Professor Lavelle talked about how when writing electron configurations, we should do, for example with Scandium, [insert noble gas]3d^1 4s^2 and NOT [noble gas]4s^2 3d^1. However, in my high school chemistry class, we always flipped 4s and 3d - I'm wondering why this is? I also un...
by Jessica Li 4F
Mon Oct 14, 2019 4:41 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty Equation
Replies: 4
Views: 57

Re: Uncertainty Equation

Just using the equation, (uncertainty in momentum)(uncertainty in position) >= h/4pi, you can tell that if one of the factors increases and you want the product to stay the same, the other factor must decrease.
Hope this helps!
by Jessica Li 4F
Mon Oct 14, 2019 4:39 pm
Forum: DeBroglie Equation
Topic: HW Question 1B.23
Replies: 2
Views: 57

Re: HW Question 1B.23

To add on, all such values should be given on the reference sheet, especially for tests, including the mass of an electron as well.
by Jessica Li 4F
Mon Oct 14, 2019 4:36 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Post-Module Question
Replies: 3
Views: 56

Re: Atomic Spectra Post-Module Question

I agree with the above answers. Although you get a negative value for frequency when you calculate using the equation, it is because frequency is emitted and therefore "lost." When anything is "lost," it will be expressed as a negative value in an equation. However, the actual fr...
by Jessica Li 4F
Mon Oct 14, 2019 4:31 pm
Forum: Properties of Light
Topic: 1A.15
Replies: 4
Views: 100

Re: 1A.15

Yeah, you have to assume that the final energy level is n = 1. Then you can find the energy emitted using the c = wavelength(frequency) equation and the E = hv equation to input into the Rydberg equation.
by Jessica Li 4F
Fri Oct 04, 2019 11:41 pm
Forum: Balancing Chemical Reactions
Topic: Reaction Stoichiometry L.35
Replies: 2
Views: 74

Re: Reaction Stoichiometry L.35

First, you should balance the equations to the following (states of matter not included): Fe + Br2 -> FeBr2 3FeBr2 + Br2 -> Fe3Br8 Fe3Br8 + 4Na2CO3 -> 8NaBr + 4CO2 + Fe3O4 Then use dimensional analysis and mole ratios to solve, from the amount of NaBr given to iron: 2.50 t NaBr * (1000 kg NaBr/1 t N...
by Jessica Li 4F
Fri Oct 04, 2019 11:27 pm
Forum: Balancing Chemical Reactions
Topic: Chemical Equations H11
Replies: 1
Views: 67

Re: Chemical Equations H11

It would be:
Fe2O3(s)+3CO(g)-->2Fe(s)+3CO2(g)
by Jessica Li 4F
Fri Oct 04, 2019 11:26 pm
Forum: Molarity, Solutions, Dilutions
Topic: Question
Replies: 3
Views: 80

Re: Question

You are supposed to multiply by 1000 to convert the liters in the Molarity measurement (which is moles/liters) into mL, and there are 1000 mL in one liter.
by Jessica Li 4F
Fri Oct 04, 2019 8:13 pm
Forum: Balancing Chemical Reactions
Topic: M9
Replies: 2
Views: 71

Re: M9

It's basically the same as any other equation, except for the compounds that are ionic and soluble in water add the (aq) subscript on the bottom. For the solids, indicate that they are solid and write them as whole compounds. However, there are also complete ionic equations in which you have to sepa...
by Jessica Li 4F
Fri Oct 04, 2019 8:10 pm
Forum: Limiting Reactant Calculations
Topic: Percent or theoretical yield
Replies: 14
Views: 715

Re: Percent or theoretical yield

I think we might, but the simple answer is just that in real life, things never go exactly right. There is a lot of potential for experimental error, as well as secondary reactions that make the actual yield lesser than the theoretical yield.
by Jessica Li 4F
Fri Oct 04, 2019 8:08 pm
Forum: Empirical & Molecular Formulas
Topic: L. 39
Replies: 2
Views: 87

Re: L. 39

To elaborate on the previous answer, for part a you want to make sure to subtract the crucible weight from the total weight to find the weight of the product itself, and then take the given mass of tin to find the percentages of both tin and oxygen, as they are the only two elements involved in the ...
by Jessica Li 4F
Fri Oct 04, 2019 8:03 pm
Forum: SI Units, Unit Conversions
Topic: SI Units
Replies: 3
Views: 86

Re: SI Units

The SI units themselves don't ascend and descend in orders of 3. I think the orders of 3 just make it a bit more convenient when converting SI units between each other, and so you don't have to memorize and name all the different powers of 10. The only major exception, as Professor Lavelle said, is ...
by Jessica Li 4F
Fri Oct 04, 2019 7:58 pm
Forum: Administrative Questions and Class Announcements
Topic: First Test in Discussion
Replies: 13
Views: 263

Re: First Test in Discussion

I like to scan or skim the problems that we need to do and see which ones are similar. Usually problems with consecutive numbers are more or less the same (i.e. E7 and E9), so if they are similar, I tend to only do one. I also tend to go for the problems later on in each Fundamentals chapter (i.e. M...
by Jessica Li 4F
Fri Oct 04, 2019 7:51 pm
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 134
Views: 102830

Re: Reading the textbook [ENDORSED]

I used these for my AP Chemistry class in high school, but I think they have some college-level chem as well: https://chem.libretexts.org/ https://www.youtube.com/channel/UCEWpbFLzoYGPfuWUMFPSaoA https://www.youtube.com/watch?v=IFKnq9QM6_A&list=PLJfwA7_CzYE_qLSXH2hJkpffcrc76NjHJ Hope this helps!

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