Search found 82 matches

by Leyna Dang 2H
Sun Feb 16, 2020 11:20 pm
Forum: Phase Changes & Related Calculations
Topic: Negative Work
Replies: 13
Views: 42

Re: Negative Work

When a system is doing the work, w is negative (ex. expansion), but when work is being done on a system, w is positive (ex. compression).
by Leyna Dang 2H
Sun Feb 16, 2020 11:16 pm
Forum: Balancing Redox Reactions
Topic: oxidation vs reduction
Replies: 18
Views: 46

Re: oxidation vs reduction

Oxidation occurs when a molecule loses an electron. Reduction occurs when it gains an electron.
by Leyna Dang 2H
Sun Feb 16, 2020 11:16 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: ∆G = ∆Gº + RT lnQ
Replies: 12
Views: 53

Re: ∆G = ∆Gº + RT lnQ

∆G= the change of Gibbs free energy for a system while ∆G°= the change of Gibbs free energy for a system under standard conditions
by Leyna Dang 2H
Sun Feb 16, 2020 11:12 pm
Forum: Balancing Redox Reactions
Topic: Memorizing charges
Replies: 11
Views: 40

Re: Memorizing charges

Memorizing the common ones should be fine
by Leyna Dang 2H
Sun Feb 16, 2020 11:11 pm
Forum: Van't Hoff Equation
Topic: Significance of Van't Hoff Equation
Replies: 5
Views: 16

Re: Significance of Van't Hoff Equation

Jacob Puchalski 1G wrote:I think the point was to relate K to the temperature? I might be wrong


I think it's the change in K and the change in temperature??
by Leyna Dang 2H
Sun Feb 09, 2020 9:07 pm
Forum: Calculating Work of Expansion
Topic: Constant pressure
Replies: 2
Views: 13

Constant pressure

Will constant pressure be told to us or do we have to assume it for things outside?
by Leyna Dang 2H
Sun Feb 09, 2020 9:03 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity
Replies: 2
Views: 12

Heat capacity

How is heat capacity a state function? What does that mean for heat capacities.
by Leyna Dang 2H
Sun Feb 09, 2020 8:59 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Pressure
Replies: 2
Views: 25

Re: Pressure

If the pressure change is caused by a change in volume then yes otherwise I don’t think so
by Leyna Dang 2H
Sun Feb 09, 2020 8:58 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Difference between Cv and Cp?
Replies: 8
Views: 28

Re: Difference between Cv and Cp?

Cv is for constant volume and Cp is constant pressure. I don’t think they’re the same value.
by Leyna Dang 2H
Sun Feb 09, 2020 8:56 pm
Forum: Administrative Questions and Class Announcements
Topic: Pizza Rolls REVIEW Session DOWNLOAD HERE
Replies: 65
Views: 2237

Re: Pizza Rolls REVIEW Session DOWNLOAD HERE

DesireBrown1J wrote:What was the little saying to remember the state functions other than entropy and enthalpy? The HUGS and TV one?


If you’re under Pressure and feeling Dense, all you want is to watch TV and get HUGS.
by Leyna Dang 2H
Sun Feb 09, 2020 8:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Pizza Rolls REVIEW Session DOWNLOAD HERE
Replies: 65
Views: 2237

Re: Pizza Rolls REVIEW Session DOWNLOAD HERE

DesireBrown1J wrote:Why is delta H always q but q is not always delta H? What exactly does he mean by that?

DeltaH by definition is q at constant pressure. But if q is not at constant pressure then it is not deltaH.
by Leyna Dang 2H
Fri Jan 31, 2020 12:49 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 8
Views: 42

Re: Midterm

905373636 wrote:Will it focus more on the new content than what we’ve already learned for Test 1 or just even distribution?


I'm not sure about distribution, but I'm pretty sure some of the material we were tested on for Test 1 will be on the midterm.
by Leyna Dang 2H
Fri Jan 31, 2020 12:47 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: hess's law
Replies: 13
Views: 37

Re: hess's law

Yes, they need to be on opposite sides to cancel out. When the equal number of moles of the reactant and product you're looking at are on opposite sides, they balance out and therefore cancel.
by Leyna Dang 2H
Fri Jan 31, 2020 12:40 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed vs isolated systems
Replies: 24
Views: 64

Re: Closed vs isolated systems

Closed systems are able to exchange energy, and therefore heat, with their surroundings. Isolated systems can't exchange energy with their surroundings.
by Leyna Dang 2H
Fri Jan 31, 2020 12:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ideal Gas QUestions
Replies: 8
Views: 33

Re: Ideal Gas QUestions

yes, because the molecules will have less space to move around
by Leyna Dang 2H
Fri Jan 31, 2020 12:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy Unit
Replies: 6
Views: 23

Re: Enthalpy Unit

The unit for ∆H is usually kJ/mol, but I think it would be kJ when you're given moles and expected to find the change in enthalpy.
by Leyna Dang 2H
Fri Jan 24, 2020 5:57 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy Accuracy
Replies: 6
Views: 12

Re: Bond Enthalpy Accuracy

I'm not sure but I think it has to do with the fact that the bond enthalpies of all molecules other than diatoms are averages. Since the averages are given and not the actual values, they aren't as accurate.
by Leyna Dang 2H
Fri Jan 24, 2020 5:52 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating Delta H
Replies: 3
Views: 18

Re: Calculating Delta H

He ended the lecture on method 3 today so we'll probably go over it in the next lecture.
by Leyna Dang 2H
Fri Jan 24, 2020 5:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q<K
Replies: 11
Views: 44

Re: Q<K

When Q<K, the forward reaction is favored because the concentrations/partial pressures of the products are too low compared to reactants for equilibrium. Therefore, the excess reactants would form more products in order to reach equilibrium.
by Leyna Dang 2H
Fri Jan 24, 2020 4:21 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Calculating K
Replies: 15
Views: 58

Re: Calculating K

Make sure you balance all of your equations. Not doing so could cause you to end up with the wrong K value since your coefficients might be wrong.
by Leyna Dang 2H
Fri Jan 24, 2020 4:18 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: pka
Replies: 4
Views: 18

Re: pka

No, strong acids would have a lower pka
by Leyna Dang 2H
Fri Jan 17, 2020 4:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and Equilibrium
Replies: 9
Views: 28

Re: Solids and Equilibrium

Neither of them affect the equilibrium or equilibrium constant because they're pure substances. Solids don't have a concentration, and liquids act as solvents and their concentrations don't change.
by Leyna Dang 2H
Fri Jan 17, 2020 4:45 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE tables
Replies: 5
Views: 26

Re: ICE tables

you usually use ice tables when the initial concentration is given
by Leyna Dang 2H
Fri Jan 17, 2020 4:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Value of Kw
Replies: 6
Views: 25

Re: Value of Kw

Yes, at 25 degrees celcius, Kw will always be equal to 1.0 x 10^-14
by Leyna Dang 2H
Fri Jan 17, 2020 4:14 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: ICE table
Replies: 11
Views: 34

Re: ICE table

You use the ICE table for weak acids and bases (doesn't fully dissociate)
by Leyna Dang 2H
Fri Jan 17, 2020 4:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Tips for Test
Replies: 16
Views: 60

Re: Tips for Test

You should work on the practice homework problems and review your lecture notes. You could even work on problems together with your friends and go over what you guys need more help/clarification on.
by Leyna Dang 2H
Thu Jan 09, 2020 10:38 pm
Forum: Ideal Gases
Topic: Understanding Q
Replies: 13
Views: 65

Re: Understanding Q

I understand the fact that you omit solids and liquids when calculating the equilibrium constant, but why? What's the logic behind it? Solids and liquids aren't included because they do not have a significant effect on the concentration. Lavelle also mentioned during lecture that solids do not have...
by Leyna Dang 2H
Thu Jan 09, 2020 10:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Meaning of equilibrium constant
Replies: 5
Views: 44

Re: Meaning of equilibrium constant

neither the reactants nor the products are strongly favored
by Leyna Dang 2H
Thu Jan 09, 2020 9:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K and Q Values
Replies: 5
Views: 24

Re: K and Q Values

No, the reverse reaction is favored because the concentration/partial pressure of the reactants is less than that of the products. Therefore, more reactants need to be produced so that the reaction can reach equilibrium. (Hope this is right and helpful!)
by Leyna Dang 2H
Thu Jan 09, 2020 9:44 pm
Forum: Ideal Gases
Topic: Reaction Quotient (Q)
Replies: 8
Views: 30

Re: Reaction Quotient (Q)

When a reaction isn't at equilibrium, you would try to find the reaction quotient, Q, in order to determine which direction the reaction will favor. When Q<K, the FORWARD (goes toward products) reaction is favored because the concentrations/partial pressures of the products are too low compared to r...
by Leyna Dang 2H
Thu Jan 09, 2020 8:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: solids and liquids
Replies: 6
Views: 24

Re: solids and liquids

Solids are not included in the equilibrium constant because they do not have a concentration. Liquids are also not included because they are in excess and their concentrations do not change (it stays constant throughout the reaction).
by Leyna Dang 2H
Sun Dec 08, 2019 8:04 pm
Forum: Hybridization
Topic: Pi bond
Replies: 10
Views: 56

Re: Pi bond

Pi bonds are unhbyrdizied p orbitals and can also be d orbitals i think
by Leyna Dang 2H
Sun Dec 08, 2019 8:03 pm
Forum: General Science Questions
Topic: Polarizbity
Replies: 2
Views: 64

Re: Polarizbity

If you are referring to the final, I think it asked about more polarizing, not polarizability. The above answer looks right.
by Leyna Dang 2H
Sun Dec 08, 2019 8:00 pm
Forum: Lewis Acids & Bases
Topic: memorizing ligands
Replies: 5
Views: 80

Re: memorizing ligands

Guess we didnt really have to memorize it since there was no naming on the final...
by Leyna Dang 2H
Sun Dec 08, 2019 7:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: vsepr formula
Replies: 7
Views: 51

Re: vsepr formula

You'd use the AXE formula where you'd look at the central atom of the compound and determine how many atoms are bonded to it and how many lone pairs it has.
by Leyna Dang 2H
Sun Dec 08, 2019 7:53 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH formula?
Replies: 21
Views: 402

Re: pH formula?

You could find pH using pH=-log[H+]. Or, if you have the pOH, you could subtract it from 14 to find the pH.
by Leyna Dang 2H
Sun Dec 01, 2019 4:35 pm
Forum: Naming
Topic: Roman numerals
Replies: 6
Views: 29

Re: Roman numerals

You can determine the roman numeral by finding the charge of the transition metal. If the charge is not given, you can calculate the charges of each ligand and subtracting it from the overall charge.
by Leyna Dang 2H
Sun Dec 01, 2019 4:29 pm
Forum: Student Social/Study Group
Topic: Final Topics
Replies: 4
Views: 35

Re: Final Topics

We didn't really focus on spectroscopy, so I don't think we'll see in on the final?? I'd focus more on what he went over in class.
by Leyna Dang 2H
Sun Dec 01, 2019 4:26 pm
Forum: Sigma & Pi Bonds
Topic: Drawing Sigma and Pi bonds
Replies: 7
Views: 54

Re: Drawing Sigma and Pi bonds

You would label the sigma and pi bonds separately for the double bond. The same would apply for a triple bond.

And yes, when there are multiple single bonds, labeling every single bond with a sigma is correct.
by Leyna Dang 2H
Sun Dec 01, 2019 3:54 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Number
Replies: 6
Views: 39

Re: Coordination Number

You can determine the coordination number by counting the number of ligands that are bonded with the central atom. For Ba[FeBr4]2, you would focus on what is in the bracket. Iron, the transition metal, has 4 ligands bonded to it. Therefore, the coordination number for your example would be 4.
by Leyna Dang 2H
Sun Dec 01, 2019 2:03 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate = more than one lone pair?
Replies: 4
Views: 31

Re: Polydentate = more than one lone pair?

Polydentate ligands have two or more lone pair donating sites.
by Leyna Dang 2H
Sun Nov 24, 2019 1:36 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: dipole-dipole in a solid phase vs gas phase
Replies: 15
Views: 94

Re: dipole-dipole in a solid phase vs gas phase

Dipole-dipole in a solid phase would be stronger. The bonds in a solid are tightly held and rigid unlike those of a gas. This would mean that the attraction between the molecules in the solid phase would be greater.
by Leyna Dang 2H
Sun Nov 24, 2019 1:28 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: AXE formula
Replies: 32
Views: 1732

Re: AXE formula

Yes, it's definitely possible! You just have to be able to know which formula corresponds with which shape.
by Leyna Dang 2H
Sun Nov 24, 2019 1:26 am
Forum: General Science Questions
Topic: Sig Figs
Replies: 7
Views: 82

Re: Sig Figs

Honestly I think it depends on your TA, but just to be safe you should use the right number of sig figs.
by Leyna Dang 2H
Sun Nov 24, 2019 1:20 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs linear
Replies: 56
Views: 300

Re: Bent vs linear

You could draw the Lewis structure and determine the VSEPR formula. A formula of AX2E or AX2E2 would indicate that the molecule is bent. AX2 or AX2E3 would be linear.
by Leyna Dang 2H
Sun Nov 24, 2019 1:15 am
Forum: Naming
Topic: Prefixes
Replies: 4
Views: 36

Re: Prefixes

EthanPham_4D wrote:Can anyone provide an example of the naming with these prefixes? I would like to see how it's used.


An example could be the compound ChloroBISethyleneDIaminecobalt(III)Sulfate. Because the ligand has the same prefix as the polydentate (di-), the second prefix, bis- is used.
by Leyna Dang 2H
Thu Nov 14, 2019 11:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lewis Structures & VSEPR
Replies: 9
Views: 43

Re: Lewis Structures & VSEPR

I don't think it's necessary, but I think it can help you determine the VSEPR structure if there are lone pairs.
by Leyna Dang 2H
Thu Nov 14, 2019 11:28 pm
Forum: Hybridization
Topic: Pi and Sigma Bonds
Replies: 17
Views: 328

Re: Pi and Sigma Bonds

A single bond would have 1 sigma bond, a double bond would have a sigma bond and a pi bond, and a triple bond would have a sigma bond and 2 bonds.
by Leyna Dang 2H
Thu Nov 14, 2019 10:51 pm
Forum: Ionic & Covalent Bonds
Topic: covalent bonds
Replies: 7
Views: 54

Re: covalent bonds

There are three types of covalent bonds: polar, nonpolar, and coordinate. Polar and nonpolar covalent bonds can be distinguished by differences in electronegativities and coordinate covalent bonds involve sharing electrons in order to order fill up shells.
by Leyna Dang 2H
Thu Nov 14, 2019 11:41 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Formula
Replies: 3
Views: 27

Re: VSEPR Formula

The VSEPR formula is AXnEm, where A is the central atom, Xn represents the atoms attached to the central atom, and Em represents the lone electron pairs.
by Leyna Dang 2H
Thu Nov 14, 2019 11:23 am
Forum: Administrative Questions and Class Announcements
Topic: TEST 2
Replies: 8
Views: 55

Re: TEST 2

I'm guessing everything we covered after the midterm?
by Leyna Dang 2H
Sun Nov 10, 2019 4:41 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Equation?
Replies: 12
Views: 48

Re: Formal Charge Equation?

You could use Formal Charge= Valence Electrons + (Lone Pairs - Bonds/2), but an easier way to calculate the formal charge is to check the valence electron of the element and subtract the number of dots and lines it has.
by Leyna Dang 2H
Sun Nov 10, 2019 4:36 pm
Forum: Photoelectric Effect
Topic: frequency and ejection of electrons
Replies: 7
Views: 51

Re: frequency and ejection of electrons

According to the photoelectric effect, frequency is directly proportional to the ejection of electrons. However, these electrons will only be ejected if the threshold energy is met.
by Leyna Dang 2H
Sun Nov 10, 2019 4:30 pm
Forum: Lewis Structures
Topic: Exceptions like Xenon
Replies: 3
Views: 19

Re: Exceptions like Xenon

Elements that can go into the d-orbital can follow the same exception and have more than 8 electrons.
by Leyna Dang 2H
Sun Nov 10, 2019 4:11 pm
Forum: Administrative Questions and Class Announcements
Topic: UA Workshops 11/11
Replies: 2
Views: 31

Re: UA Workshops 11/11

I don't think there are
by Leyna Dang 2H
Sun Nov 10, 2019 4:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: how to draw lewis structure
Replies: 9
Views: 331

Re: how to draw lewis structure

Count the valence electrons, try to make each element form a complete octet, and then check your formal charges.
by Leyna Dang 2H
Sat Nov 02, 2019 12:16 pm
Forum: DeBroglie Equation
Topic: Question about Converting Units
Replies: 3
Views: 46

Re: Question about Converting Units

the conversion from eV to J should be given on the test I think
by Leyna Dang 2H
Sat Nov 02, 2019 12:16 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Energy change and Energy of photon
Replies: 5
Views: 29

Re: Energy change and Energy of photon

Going from a higher energy level to a lower, the change is negative, but photon energy is always positive, so if you set them equal to each other you would need a negative sign.
by Leyna Dang 2H
Sat Nov 02, 2019 12:13 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: General Question about Orbital... Filling..?
Replies: 5
Views: 30

Re: General Question about Orbital... Filling..?

Yes I am pretty sure you have to write it in order of increasing number or you will lose points. It also helps when writing configurations for cations to tell which electrons to remove.
by Leyna Dang 2H
Sat Nov 02, 2019 12:12 pm
Forum: Trends in The Periodic Table
Topic: Electronegativity trend exception
Replies: 3
Views: 25

Re: Electronegativity trend exception

Lyndon was talking about an exception to the trend with ionization energy and electron affinity. Electronegativity does not have those same exceptions. O is more electronegative than N.
by Leyna Dang 2H
Sat Nov 02, 2019 12:09 pm
Forum: Photoelectric Effect
Topic: Work Function
Replies: 6
Views: 40

Re: Work Function

It is the threshold energy, or the energy required to remove an electron from a metal surface. The threshold energy will vary based on the type of each metal. When the unit is J/mol, it is calculating the energy required to remove a mol of electrons.
by Leyna Dang 2H
Sat Nov 02, 2019 12:05 pm
Forum: Lewis Structures
Topic: Valence Electrons from Periodic Table
Replies: 10
Views: 77

Re: Valence Electrons from Periodic Table

You can look at the group numbers on the periodic table, but this doesn’t apply to d-block elements. For groups 13-18, the valence electrons correspond to the number that is in the ones place. So oxygen, for instance, is in group 16 so it would have 6 valence electrons.
by Leyna Dang 2H
Wed Oct 23, 2019 5:10 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 2A.5
Replies: 4
Views: 27

Re: 2A.5

I had problems with this at first too, but I think it has to do with the element being ionized. You're supposed to fill the d block first so that it's more stable(?), and you do this by taking the 2 electrons from the 4s orbital and moving them to the 3d orbital. This now makes the configuration for...
by Leyna Dang 2H
Wed Oct 23, 2019 4:49 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: electron configurations
Replies: 2
Views: 17

Re: electron configurations

I think you meant [He] haha but anyways, I think one thing you could do is count up the number of electrons in the given configuration and compare the total to the element on the periodic table that has the total as its atomic number. If the elements match, then the configuration is in the grounded ...
by Leyna Dang 2H
Wed Oct 23, 2019 4:36 pm
Forum: Lewis Structures
Topic: Finding Valence Electrons
Replies: 8
Views: 51

Re: Finding Valence Electrons

The number of valence electrons an element has corresponds with the group/ column it is under on the periodic table. For example, oxygen is in group 6 of the periodic table, therefore it has 6 valence electrons.

Hope this helps!
by Leyna Dang 2H
Wed Oct 23, 2019 4:18 pm
Forum: Trends in The Periodic Table
Topic: Trend in periodic table
Replies: 6
Views: 23

Re: Trend in periodic table

Going down the table, elements in the same column, or group, have the same number valence electrons and share similar characteristics.
by Leyna Dang 2H
Wed Oct 23, 2019 12:49 pm
Forum: Ionic & Covalent Bonds
Topic: Difference Between Ionic and Covalent
Replies: 8
Views: 309

Re: Difference Between Ionic and Covalent

An ionic bond is a bond that is shared between a metal and a non-metal. These metals can also be referred to as ions (atom/molecule that loses or gains an electron). Ions that gain an electron (have a negative charge) are known as anions and those that lose electrons (positively charged) are cations...
by Leyna Dang 2H
Sun Oct 20, 2019 7:22 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Best Way To Study?
Replies: 56
Views: 390

Re: Best Way To Study?

So far, I've been reviewing the modules on Lavelle's website and worked on all of the homework problems listed on the class syllabus.
by Leyna Dang 2H
Sun Oct 20, 2019 12:07 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions for Electron Configuration
Replies: 6
Views: 24

Re: Exceptions for Electron Configuration

I believe they were copper (Cu) and chromium (Cr). The configuration for copper would be [Ar]3d10 4s1 and chromium would be [Ar]3d5 4s1.
by Leyna Dang 2H
Sun Oct 20, 2019 12:05 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configurations for Ni and Sc
Replies: 1
Views: 16

Re: Electron configurations for Ni and Sc

On the periodic table, 3d starts from Scandium (Sc) and ends at Zinc (Zn). You can think of it as each element having a humber that corresponds with their position or order in that row. So Sc would be 1, Ti would be 2,..etc. Because Sc is first in the 3d row its configuration would be [Ar]3d1 4s2 an...
by Leyna Dang 2H
Sun Oct 20, 2019 11:56 am
Forum: Properties of Light
Topic: 1A.9 Energy of Photon
Replies: 12
Views: 80

Re: 1A.9 Energy of Photon

You can try to solve for the frequency and once you get that, use the formula E= (Plank's constant)*(frequency), or E=hv, in order to get the energy of the photon. If you are given the wavelength and not the frequency, you could use wavelength to find the frequency by using formula v (frequency) = s...
by Leyna Dang 2H
Tue Oct 15, 2019 10:02 pm
Forum: Properties of Light
Topic: Homework 1A.15
Replies: 1
Views: 33

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."

I'm not sure how to approach this problem. Can someone help?
by Leyna Dang 2H
Sun Oct 13, 2019 1:58 pm
Forum: General Science Questions
Topic: Units question for 1B.5
Replies: 2
Views: 24

Re: Units question for 1B.5

keV is the notation for kiloelectron volt. If you want to convert this to joules you could convert keV into units of eV by multiplying the amount given in keV by 1000 eV/1keV to cancel out the keV's. Now that your units are in eV you could convert eV into joules by using the conversion factor 1 eV =...
by Leyna Dang 2H
Sun Oct 13, 2019 1:35 pm
Forum: Quantum Numbers and The H-Atom
Topic: Circular Standing Waves and "in phase"
Replies: 2
Views: 31

Re: Circular Standing Waves and "in phase"

The textbook uses "in phase" to describe the relationship between two waves. When both waves have the same frequencies and coincide with each in terms of their peaks and troughs, they're said to be in phase. "Out of phase", on the other hand, would mean that the troughs of one of...
by Leyna Dang 2H
Sun Oct 13, 2019 4:58 am
Forum: Properties of Electrons
Topic: Electron Quantum Energies
Replies: 3
Views: 29

Re: Electron Quantum Energies

The relationship between a particle's wavelength and its energy is what establishes the quantization of energy levels. Imagine a particle that's in a box. Unlike classical mechanics which states that the energy of an object could be at any value, the particle could bounce off on any direction of the...
by Leyna Dang 2H
Sat Oct 12, 2019 11:12 pm
Forum: Balancing Chemical Reactions
Topic: F.3
Replies: 5
Views: 64

Re: F.3

I'm not sure if we are expected to derive the formulas on our own, but hopefully this helps: For part a, it helps to know that acids contain hydrogen and usually begin with an H. So, that gives you the first element of nitric acid. For the rest of the formula, I had to work backward. When you are us...
by Leyna Dang 2H
Fri Oct 11, 2019 4:30 pm
Forum: Significant Figures
Topic: Sig Figs in Answer
Replies: 8
Views: 87

Re: Sig Figs in Answer

Because it's not specified, I think using 3 or 4 sig figs would be fine. Having 4 sig figs would make your answer a bit more accurate, but I think using 3 would also be completely fine.
by Leyna Dang 2H
Sat Oct 05, 2019 10:28 pm
Forum: SI Units, Unit Conversions
Topic: Negative and Non-Negative powers
Replies: 2
Views: 42

Re: Negative and Non-Negative powers

You have the right idea! Positive powers indicate that you move the decimal point to the right, while negative powers indicate that you move the decimal point to the left. So keeping that in mind, giga- would be in factors of 1,000,000,000 while nano- would be .000000001.
by Leyna Dang 2H
Sat Oct 05, 2019 10:21 pm
Forum: SI Units, Unit Conversions
Topic: Fundamentals E.9
Replies: 2
Views: 41

Re: Fundamentals E.9

For B, you don't need to use your answer from A in order to find your formula units! In order to get your formula units when you're given the grams of a sample, you'd have divide it by the molar mass of the sample (in this case, it is 246.46 g/mol which you get this by adding up the mass of each ele...
by Leyna Dang 2H
Sat Oct 05, 2019 10:12 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E.15
Replies: 4
Views: 57

Re: E.15

I needed clarification on this too. Why does finding "sulfide" indicate that we have to subtract (OH)2? Is sulfide just used as a broader term for nonmetal??
by Leyna Dang 2H
Sat Oct 05, 2019 9:54 pm
Forum: SI Units, Unit Conversions
Topic: Unit Conversion
Replies: 5
Views: 43

Re: Unit Conversion

Yeah, if you know the unit conversions like 1 kg = 1000 g, you could use that to convert a given unit to your desired unit. Just remember to line up your units correctly so that they can cancel out. This can apply to other units like 1 g = 1000 mg too. Hope this helps!
by Leyna Dang 2H
Thu Oct 03, 2019 1:22 am
Forum: SI Units, Unit Conversions
Topic: Easy method to memorize prefixes?
Replies: 2
Views: 49

Re: Easy method to memorize prefixes?

Hi! I also came up with an acronym to memorize all the prefixes more easily. It's: Give Mighty King Daniel Cozy Mozy Mittens, Not Pants. Hopefully this helps, but you'd have to be able to memorize and differentiate between the two M's for milli- and micro-. It could get confusing sometimes.

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