Search found 31 matches

by Danielle Sumilang - 1F
Mon Jun 11, 2018 11:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Effect of Lone Pairs on Polarity
Replies: 1
Views: 155

Effect of Lone Pairs on Polarity

Hello!

I understand that symmetry and electronegativity influence polarity but I was wondering how lone pairs affect whether or not a molecule is polar. Thank you!
by Danielle Sumilang - 1F
Mon Jun 11, 2018 11:43 pm
Forum: Lewis Acids & Bases
Topic: identifying strong acids
Replies: 2
Views: 223

Re: identifying strong acids

Hello! I don't think that the strong acids are grouped together like the strong bases. The best way to know what elements create strong acids is to memorize it. I have attached a website below that lists out the 7 common strong acids. Hope that helps! https://www.thoughtco.com/list-of-the-strong-aci...
by Danielle Sumilang - 1F
Sat Jun 09, 2018 10:46 pm
Forum: Hybridization
Topic: sigma vs pi bonds
Replies: 4
Views: 229

Re: sigma vs pi bonds

Hello! Sigma bonds occur when orbitals overlap from end to end. Pi bonds occur when orbitals overlap from side to side. Sigma bonds also allow bound atoms to rotate. If I'm not mistaken, sigma bonds can form when there is an s-s orbital overlap or an s-p orbital overlap while pi bonds form only when...
by Danielle Sumilang - 1F
Wed Jun 06, 2018 8:35 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand binding
Replies: 4
Views: 128

Re: Ligand binding

Hello!

A tip that a UAs told me in order to find a binding site was to look for O- (oxygen with a formal charge of -1) or a Nitrogen with a lone pair.
by Danielle Sumilang - 1F
Sun Jun 03, 2018 10:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Radical
Replies: 4
Views: 113

Radical

Hello!

How would the VSEPR formula be written for a central atom that is a radical? Usually the subscript by E denotes a lone pair (ex. E2 means there are 2 lone pairs or 4 lone pair electrons). Thank you!
by Danielle Sumilang - 1F
Sat Jun 02, 2018 3:29 pm
Forum: Biological Examples
Topic: Biological Function
Replies: 2
Views: 204

Re: Biological Function

Hello!

B12 refers to vitamin B12, which is a vitamin that keeps red blood cells and nerve cells healthy. It also helps form DNA molecules. The biological function of cobalt is that it is the core element in vitamin B12.
by Danielle Sumilang - 1F
Sat Jun 02, 2018 3:21 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination compounds
Replies: 2
Views: 96

Coordination compounds

Hello!

I am a little confused on what a coordination compound actually is. I wrote in my notes that adding NH3 or K+CN- or Na+Cl- and the e- rich species replaces the H20 ligands is the easiest way to make coordination compounds. Can someone please explain what is meant by that? Thank you!
by Danielle Sumilang - 1F
Sat May 26, 2018 11:18 pm
Forum: Ionic & Covalent Bonds
Topic: 6.11
Replies: 2
Views: 131

6.11

Hello!

6.11 lists several molecules, such as PH3 and HBr, and asks which of the molecules are more likely to form hydrogen bonds. What exactly are hydrogen bonds and how are we able to predict what kind of molecules form it? Thank you!
by Danielle Sumilang - 1F
Sat May 26, 2018 9:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Types of Bonds
Replies: 6
Views: 160

Re: Types of Bonds

Hello!

The difference between the two bonds is from how the orbitals overlap. Sigma bonds occur when orbitals overlap from end to end. It kind of resembles a Venn diagram. Pi bonds occur when orbitals overlap from side to side.
by Danielle Sumilang - 1F
Mon May 21, 2018 11:21 pm
Forum: Lewis Structures
Topic: 3.63
Replies: 1
Views: 73

3.63

Hello! I understand that the central atoms in question 3.63 have expanded octets but how do I know how many electrons the central atom has exactly? For example, 3.63b has the element XeF2. I drew the Lewis structure normally and I expected Xe to only have 8 electrons but the solutions manual says Xe...
by Danielle Sumilang - 1F
Sun May 20, 2018 10:32 pm
Forum: Ionic & Covalent Bonds
Topic: ionic character
Replies: 10
Views: 253

Re: ionic character

Thank you! This was really helpful!!! How would I be able to determine which element of the compound is more electronegative? Hello! You can determine if the element is more electronegative by using the periodic table trends we learned before the midterm. Electronegativity increases as you move fro...
by Danielle Sumilang - 1F
Sun May 20, 2018 10:24 pm
Forum: Ionic & Covalent Bonds
Topic: ionic character
Replies: 10
Views: 253

Re: ionic character

Hello! You're pretty much right. If a compound has a greater ionic character, then the ionic bond between the two elements is stronger than the elements in the other compound. A larger ionic character is caused by a great difference in electronegativity. One element in the compound is more electrone...
by Danielle Sumilang - 1F
Thu May 17, 2018 8:03 pm
Forum: Lewis Structures
Topic: Question about Test 3 Material [ENDORSED]
Replies: 2
Views: 114

Question about Test 3 Material [ENDORSED]

Hello! There is an announcement on the class website that says that Test 3 will cover Chapter 3 material. Will we be tested on electron configurations because it is included in Chapter 3 or will the test only include Lewis Structures because we were already tested on electron configurations on the m...
by Danielle Sumilang - 1F
Sun May 13, 2018 11:24 pm
Forum: Lewis Structures
Topic: Valence Electrons [ENDORSED]
Replies: 2
Views: 70

Valence Electrons [ENDORSED]

Hello! What is the significance of valence electrons in identifying formal charge and drawing Lewis structures? I understand that there must be only eight electrons due to the octet rule but the number of valence electrons differs from element to element. I am a little confused about applying both t...
by Danielle Sumilang - 1F
Sun May 13, 2018 2:53 pm
Forum: Ionic & Covalent Bonds
Topic: 3.29
Replies: 6
Views: 207

3.29

Hello!

The question is asking which pairs of ions would have the greatest coulombic attraction in a solid compound. What is coulombic attraction?
by Danielle Sumilang - 1F
Tue May 08, 2018 5:15 pm
Forum: SI Units, Unit Conversions
Topic: units
Replies: 4
Views: 268

Re: units

Hello!

Whenever the equation uses mass, like the kinetic energy equation and the De Broglie equation, the mass needs to be in kilograms (kg). Energy has to be in joules(J) and the wavelength must be in meters(m).
by Danielle Sumilang - 1F
Sun May 06, 2018 10:36 pm
Forum: Molarity, Solutions, Dilutions
Topic: Midterm Prep Worksheet- Molarity [ENDORSED]
Replies: 2
Views: 177

Re: Midterm Prep Worksheet- Molarity [ENDORSED]

Hello!

I don't think the 75 ml volume is relevant because the final volume of the solute was 125 ml. Therefore, 125 ml is used in the equation to find the molarity.
by Danielle Sumilang - 1F
Sat May 05, 2018 9:52 pm
Forum: Significant Figures
Topic: Sig Figs in Heisenberg Uncertainty Principle
Replies: 3
Views: 289

Re: Sig Figs in Heisenberg Uncertainty Principle

Hello!

The answer would have 1 sig fig because we use the smallest number of sig figs in the numbers given by the question. In this case, the uncertainty in velocity has 1 sig fig and that is the smallest amount of sig figs given so the answer would have 1 sig fig as well.
by Danielle Sumilang - 1F
Wed May 02, 2018 12:00 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ground state for Sc
Replies: 2
Views: 58

Re: Ground state for Sc

Hello! To answer your first question, once there is an electron in the 3d orbital (ex. 3d^1), the 3d orbital has less energy than the 4s orbital. Therefore, 3d is written before 4s. To answer the second question, [Ar] is present because that is the last noble gas before the element. The last noble g...
by Danielle Sumilang - 1F
Sun Apr 29, 2018 9:59 pm
Forum: Quantum Numbers and The H-Atom
Topic: Orientation of Lobes
Replies: 3
Views: 153

Re: Orientation of Lobes

Hello!

Specifically, the quantum number that corresponds to the orientation in space is ml. X,Y, and Z are used to describe the orientation on the plane.
by Danielle Sumilang - 1F
Sat Apr 28, 2018 11:34 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Example 1.7a in the Textbook [ENDORSED]
Replies: 4
Views: 158

Example 1.7a in the Textbook [ENDORSED]

Hello! Can someone please explain how the uncertainty in the position of a marble of mass 1.0 g given that its speed is known to within 1.0 mm s^-1 was calculated? I understand that the equation for the uncertainty principle is delta p x delta >= 1/2 h bar, but where did the equation delta p = m tim...
by Danielle Sumilang - 1F
Mon Apr 23, 2018 10:47 pm
Forum: DeBroglie Equation
Topic: When to use DeBroglie or Ek equation
Replies: 7
Views: 278

When to use DeBroglie or Ek equation

Hello!

If the velocity is given in a problem, how do I know whether to use the DeBroglie equation(wavelength=h/p) or the Kinetic energy equation(Ek=1/2mv^2)?
by Danielle Sumilang - 1F
Sun Apr 22, 2018 4:47 pm
Forum: Properties of Light
Topic: HW Question 1.57
Replies: 3
Views: 97

Re: HW Question 1.57

Thank you so much! That was really helpful. Should the wavelength always be given in nm or would it be ok to just leave the answer in meters?
by Danielle Sumilang - 1F
Sat Apr 21, 2018 10:02 pm
Forum: Properties of Light
Topic: HW Question 1.57
Replies: 3
Views: 97

HW Question 1.57

Hello!

I am having a little trouble figuring out this question. It states that lines in the Balmer series of the hydrogen spectrum are observed at 656.3, 486.1, 434.0, 410.2 nm and asks to find the wavelength of the next line in the series. How would I begin the problem?
by Danielle Sumilang - 1F
Wed Apr 18, 2018 12:13 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: HW Question 1.23
Replies: 1
Views: 52

HW Question 1.23

The question gives the energy of the photons as 140.511 keV. How do I convert it to joules? The solutions manual says to multiply (140.511 x 10^3 eV)(1.6022 x 10^-19 J x eV^-1) but I don't understand where the numbers came from. Thank You!
by Danielle Sumilang - 1F
Sun Apr 15, 2018 10:05 pm
Forum: Photoelectric Effect
Topic: work function given in kJ*mol^-1
Replies: 2
Views: 69

Re: work function given in kJ*mol^-1

Hello!

You should divide the work function by Avogadro's number to get rid of the mol^-1.
by Danielle Sumilang - 1F
Sun Apr 15, 2018 10:00 pm
Forum: Photoelectric Effect
Topic: When to use Planck's Constant [ENDORSED]
Replies: 5
Views: 188

Re: When to use Planck's Constant [ENDORSED]

You use Planck's Constant(h) when finding the energy of a photon (E=hv). Based off of this equation, we know that Energy and frequency are directly proportional. If I'm not mistaken, I remember Dr. Lavelle mentioned in the Photoelectric module video that when you graph the energy of the photon again...
by Danielle Sumilang - 1F
Sun Apr 15, 2018 12:58 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Formula, 1.13 HW
Replies: 4
Views: 142

Re: Rydberg Formula, 1.13 HW

Hello! In order to find the change in energy level, the equation is E(final)-E(initial). Another way of thinking about this is if the temperature is 40 degrees F in the afternoon but it drops to 20 degrees F in the night, the change in temperature is -20 degrees F (change in temperature= final temp ...
by Danielle Sumilang - 1F
Sun Apr 08, 2018 3:03 pm
Forum: Photoelectric Effect
Topic: Module Question 27.A
Replies: 4
Views: 158

Module Question 27.A

Hello! I had a little difficulty answering a question from the post-module assessment. Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. What is the kinetic energy of the ejected electron? I know that to fi...
by Danielle Sumilang - 1F
Fri Apr 06, 2018 10:05 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Module: Exercise 18 [ENDORSED]
Replies: 1
Views: 56

Limiting Reactant Module: Exercise 18 [ENDORSED]

Hello! I'm a little confused on how to solve this problem from the module. For the following equation, determine the limiting reagent if 21.4 g NH3 is reacted with 42.5 g of O2. 4NH3(g) + 5O2(g) ---> 4NO(g) + 6H2O(g) I was able to find the number of moles of NH3, which is 1.26 mol, and O2, which is ...
by Danielle Sumilang - 1F
Fri Apr 06, 2018 9:17 pm
Forum: Molarity, Solutions, Dilutions
Topic: Module Assessment Question
Replies: 3
Views: 120

Re: Module Assessment Question

Hi Angela! To find the concentration of the solution in the second flask, you should use the equation M (initial) x V(initial) = M (final) x V (final) and try to solve for M (final). Plug in the molarity of the solution in the first flask, 0.211 m/L, as your M (initial), 0.2 L as your V (initial), s...

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