## Search found 117 matches

Fri Oct 25, 2019 1:10 am
Forum: Photoelectric Effect
Topic: HW Question 1.31
Replies: 1
Views: 63

### HW Question 1.31

In a recent suspense film, two secret agents must penetrate a criminal's stronghold monitored by a lithium photomultiplier cell that is continually bathed in light from a laser. If the beam of light is broken, an alarm sounds. The agents want to use a hand- held laser to illuminate the cell while t...
Fri Oct 18, 2019 7:47 pm
Forum: Properties of Light
Topic: 1D.13
Replies: 1
Views: 31

### Re: 1D.13

b) How many values of ml are allowed for an electron in the 6d subshell? We know that a 6d subshell equates with a principal quantum number n = 6 and angular momentum quantum number l = 2. Since the allowed values of m l range between -l and l, the total possible values are -2, -1, 0, 1, 2, which m...
Fri Oct 18, 2019 7:42 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Noble planes
Replies: 1
Views: 38

### Re: Noble planes

What does it mean for something to have a noble plane and why do the p and d orbitals have it? Nodal planes are essentially areas with zero probability of electron density (in other words, the probability of finding an electron is 0). Nodal planes are present between the lobes of the p and d orbita...
Thu Oct 17, 2019 8:41 pm
Forum: Photoelectric Effect
Topic: E = pc
Replies: 3
Views: 58

### E = pc

When would we have to use the E = pc equation that is listed in the equations sheet and mentioned briefly in our notes? Can someone clarify for me in what problems/situations feature this equation? I don't think I've ever encountered it before in the homework.
Wed Oct 16, 2019 8:43 pm
Forum: Properties of Light
Topic: HW 1B15
Replies: 1
Views: 54

### Re: HW 1B15

Hi, guys! Does anyone know why you can't use the c=λv equation to derive the wavelength for part (c)? In the solutions manual, they add together the energy put in (hv) to the energy that is leaving (1/2mv^2) and then use those to find the wavelength, but I'm confused as to why that is a necessary s...
Wed Oct 16, 2019 5:07 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital and Wavefunction Clarification
Replies: 2
Views: 59

### Orbital and Wavefunction Clarification

I'm having trouble conceptually visualizing what an orbital is and how it relates to the wavefunction. Can someone help explain what exactly an orbital is, and how it relates to Schrodinger's wave function equation? To what extent do we need to know the wave function equation on upcoming exams?
Sat Oct 12, 2019 11:20 pm
Forum: DeBroglie Equation
Topic: De Broglie Lecture Question
Replies: 2
Views: 29

### Re: De Broglie Lecture Question

The mass of an electron is me = 9.109383 x 10-31 kg, so that's where the number came from in the answer. It's also on our constants and equations sheets so we don't have to memorize it.

Hopefully this helped!
Sat Oct 12, 2019 9:19 pm
Forum: Properties of Light
Topic: 1A.3
Replies: 4
Views: 54

### Re: 1A.3

(a) The speed of the radiation decreases. Speed of radiation is constant and is described as speed of light, where c = 3.00 x 10^8 m/s. (b) The wavelength of the radiation decreases. Wavelength would actually increase, because frequency and wavelength share an inversely proportional relationship, as...
Sat Oct 12, 2019 8:32 pm
Forum: Properties of Light
Topic: Help with Homework 1A.15
Replies: 3
Views: 47

### Re: Help with Homework 1A.15

In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line. First, you would find the change in energy (ΔE). The equations we know ar...
Fri Oct 11, 2019 1:56 pm
Forum: Properties of Light
Topic: HW Problem A15
Replies: 2
Views: 35

### HW Problem A15

1A.15) In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line. Is there any way to solve this without the Rydberg equation, using...
Fri Oct 11, 2019 11:56 am
Forum: Properties of Light
Topic: Equations for quantum mechanics
Replies: 3
Views: 52

### Re: Equations for quantum mechanics

c = λv or λ = c / v describes the inverse relationship between wavelength and frequency, with c = speed of light, and is used to describe electromagnetic radiation. You would use this equation when dealing with a photon of light or particles without mass. E = hv describes the energy of a photon, wit...
Fri Oct 04, 2019 12:10 am
Forum: Molarity, Solutions, Dilutions
Topic: G 13
Replies: 3
Views: 142

### Re: G 13

To prepare a fertilizer solution, a florist dilutes 1L of 2M NH4NO3 by adding 3L of Water. The florist then adds 100mL of the diluted solution to each plant. How many moles of nitrogen atoms will each plant receive? For this equation, you would need to use M1V1 = M2V2 in order to first find the fin...
Thu Oct 03, 2019 12:46 am
Forum: Limiting Reactant Calculations
Topic: M 19
Replies: 2
Views: 42

### Re: M 19

After finding the mass of C, H, and N, add them all together to find the total mass. Then subtract that total mass from 0.376, which is the mass of caffeine burned. So, roughly: 0.376 - (0.1861 + 0.01947 + 0.1100) = 0.06042 g. This amount left over should be the mass of O, which you can then convert...
Wed Oct 02, 2019 9:34 pm
Forum: Empirical & Molecular Formulas
Topic: Fundamentals Section M Homework M19
Replies: 3
Views: 93

### Re: Fundamentals Section M Homework M19

In this problem, they don't give you the mass of each element in a compound, but rather the masses of the compounds that were produced as a result of the burning of caffeine. Because of this, you have to take an extra step and "break down" the compounds into their component elements in ord...
Wed Oct 02, 2019 8:51 pm
Forum: Molarity, Solutions, Dilutions
Topic: Unit Conversion for Molarity/Dilution
Replies: 3
Views: 34

### Re: Unit Conversion for Molarity/Dilution

It's easier if you convert it to L first because it's typically the standard unit you measure volume in chemistry, unless they ask you to put it in mL.
Wed Oct 02, 2019 5:31 pm
Forum: Molarity, Solutions, Dilutions
Topic: HW problem G21
Replies: 3
Views: 60

### Re: HW problem G21

I agree with Mansi! The concentration of ions in a solution usually depend on the mole ratios between the dissolved substance in the solution and the cations and/or anions it forms — in this case, the question is asking for K+ and S 2- . After dividing the mass of each compound by the molar mass to ...
Mon Sep 30, 2019 5:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student - Part II [ENDORSED]
Replies: 150
Views: 5633

### Re: Advice from a Medical Student - Part II[ENDORSED]

Thank you so much for sharing your experience! We appreciate the time you're taking to answer our questions. When did you first decide you wanted to go to medical school? Was being pre-med something you've always known, or something you decided as the quarters went on in UCLA?