Search found 50 matches
- Sat Dec 07, 2019 12:54 pm
- Forum: Conjugate Acids & Bases
- Topic: Ammonia and Ammonium
- Replies: 2
- Views: 380
Re: Ammonia and Ammonium
I'm not 100% sure about this, but while it's true that the conjugates of weak bases/acids are stronger, they are not necessarily THAT strong. In essence, the conjugate of a weak base or acid will not always result in what we consider a strong acid/base.
Re: Metals
I think the only ones we need to know are iron and copper. In anionic complexes, they become ferrate and cuprate, respectively. You can easily remember this by looking at their atomic symbols: Fe (iron) and Cu (copper).
- Sat Dec 07, 2019 12:39 pm
- Forum: Naming
- Topic: Explanation of overall charge of ion
- Replies: 2
- Views: 290
Re: Explanation of overall charge of ion
[Pt(en)2Cl2]Cl2 is a coordination compound and coordination compounds are neutral. Because chloride has a charge of -1 and there are 2 in the compound, we can conclude that the complex ion [Pt(en)2Cl2] has an overall charge of +2. The oxidation number of platinum would be +4 because, as previously s...
- Sat Dec 07, 2019 12:27 pm
- Forum: Naming
- Topic: overall charge ion
- Replies: 1
- Views: 189
Re: overall charge ion
Coordination compounds are neutral. In this case, it seems the complex ion would probably have a charge of -4 because potassium ions have a charge of +1 and there are 4 in this compound (K4). The oxidation number of iron, however, is +2 because cyanide has a charge of -1 and there are 6. If you're l...
- Sun Nov 17, 2019 11:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Determining polarity 2E 25 pt d
- Replies: 2
- Views: 211
Re: Determining polarity 2E 25 pt d
The molecule is polar. The lone pair pushes the bonded atoms down into the see saw shape thus making the overall dipole moment point downward in the direction of all bonded atoms.
- Sun Nov 17, 2019 11:00 pm
- Forum: Hybridization
- Topic: Hybridization
- Replies: 6
- Views: 288
Hybridization
What exactly is hybridization and why are hybrid orbitals significant?
- Sun Nov 17, 2019 10:56 pm
- Forum: Ionic & Covalent Bonds
- Topic: Dispersion Forces
- Replies: 2
- Views: 231
Dispersion Forces
Why are F2 and Cl2 gases at room temp vs. Br2 and I2 which are solids at room temp?
- Sun Nov 17, 2019 10:54 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic Bond Energies
- Replies: 1
- Views: 208
Re: Ionic Bond Energies
It was definitely covered after the midterm though we haven't done much practice with it in class/discussion; however, we also haven't been given much time to as well. I would understand its significance and how to calculate Ep just in case because not much practice was done with Rydberg's equation ...
- Sun Nov 17, 2019 10:49 pm
- Forum: Ionic & Covalent Bonds
- Topic: ionic bonding
- Replies: 2
- Views: 204
Re: ionic bonding
Ionic character of a bond will increase with an increased difference in electronegativity
- Sun Nov 17, 2019 10:26 pm
- Forum: Ionic & Covalent Bonds
- Topic: Hydrogen Bonds
- Replies: 2
- Views: 192
Hydrogen Bonds
To clarify, hydrogen bonds being intermolecular forces strengthen covalent bonds and thus increase the boiling point of certain molecules? What notable influences do hydrogen bonds have on ionic bonds?
- Sun Nov 17, 2019 10:13 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: bond angles
- Replies: 8
- Views: 469
Re: bond angles
The electron-electron repulsion between the lone pairs and the bonded atoms pushes the bonded atoms farther away thus lessening the bond angle.
- Sun Nov 17, 2019 10:03 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Drawing molecules
- Replies: 12
- Views: 752
Re: Drawing molecules
It would be a good idea to know how to draw the lewis structures (obviously) and just generally know how to draw the 3D versions; however, I recall Dr. Lavelle saying we won't need to draw them on the test.
- Sun Nov 17, 2019 10:01 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs
- Replies: 2
- Views: 235
Lone Pairs
Can someone elaborate/clarify what "lone pairs do not influence molecular shape but only atom positions are used to name the shape" means? I thought lone pairs did have some part in influencing molecular shape such as in see-saw or bent. I might be misinterpreting this statement.
- Sun Nov 10, 2019 5:11 pm
- Forum: Lewis Structures
- Topic: Does the shape that I draw the Lewis structure matter?
- Replies: 14
- Views: 1038
Re: Does the shape that I draw the Lewis structure matter?
There’s a bunch of shapes that we’ll eventually learn about so yes it does matter but we don’t need to worry about it now!
- Sun Nov 10, 2019 4:59 pm
- Forum: Bond Lengths & Energies
- Topic: test 2
- Replies: 16
- Views: 926
Re: test 2
It’s cumulative
- Sun Nov 10, 2019 4:51 pm
- Forum: Bond Lengths & Energies
- Topic: Strongest Bond
- Replies: 15
- Views: 7330
Re: Strongest Bond
In terms of single/double/triple bonds, the strongest and shortest would be triple bonds and decreases in strength and increases in length with single bonds being the longest and weakest.
- Sun Nov 10, 2019 4:42 pm
- Forum: Lewis Structures
- Topic: Midterm grades
- Replies: 26
- Views: 1487
Re: Midterm grades
VioletKo3F wrote:Does anyone know if we'll get the actual midterm back? Or is it only our grades?
We get the actual midterm back I think
- Sun Nov 10, 2019 4:40 pm
- Forum: Lewis Structures
- Topic: Oxygen
- Replies: 8
- Views: 1133
Re: Oxygen
what about the ionization energy of nitrogen? Is It greater than oxygen? Yes because nitrogens subshells are completely half filled which is more stable than oxygen which has 1 pair and 2 lone electrons. The electron electron repulsion of oxygen’s orbital causes it to have a lower ionization energy...
- Sun Nov 10, 2019 4:35 pm
- Forum: Lewis Structures
- Topic: Electronegative
- Replies: 14
- Views: 870
Re: Electronegative
Yes higher electronegativity means higher attraction of electrons
- Sun Nov 10, 2019 4:34 pm
- Forum: Lewis Structures
- Topic: Formal Charges
- Replies: 15
- Views: 1012
Re: Formal Charges
Avoid putting the negative charge on the central atom but try to make most of the formal charges equal 0!
- Sun Nov 03, 2019 4:04 pm
- Forum: Ionic & Covalent Bonds
- Topic: middle atom
- Replies: 13
- Views: 558
Re: middle atom
The central atom is typically the element with the lowest ionization energy. Hydrogen can never be the central atom
- Sun Nov 03, 2019 3:55 pm
- Forum: Ionic & Covalent Bonds
- Topic: observed bond length
- Replies: 2
- Views: 153
Re: observed bond length
The observed bond length is the distance between the nuclei of two bonded atoms. Its relevant to resonance structures because resonance structures depict the possible ways in which bonds can orient themselves; however, resonance really is a blending of structures with the same arrangement of atoms b...
- Sun Nov 03, 2019 3:44 pm
- Forum: Ionic & Covalent Bonds
- Topic: Strength and Length
- Replies: 18
- Views: 959
Re: Strength and Length
Longer bonds are weaker (easily broken) and thus are more likely involved in reactions. These would be single bonds, and as you increase into double and triple bonds, they get stronger and shorter. Therefore, double bonds are shorter and stronger than single bonds and triple bonds are stronger and s...
- Sun Nov 03, 2019 3:41 pm
- Forum: Ionic & Covalent Bonds
- Topic: ionic character
- Replies: 2
- Views: 167
Re: ionic character
I think the question would be better phrased with ions causing large distortions rather than larger ions. Ions which cause large distortions have high polarizing power which makes an ionic bond have more covalent character. Covalent character implies less soluble in water as covalent compounds typic...
- Sun Nov 03, 2019 3:32 pm
- Forum: Ionic & Covalent Bonds
- Topic: Drawing Ionic Compunds
- Replies: 7
- Views: 589
Re: Drawing Ionic Compunds
Use lewis structures and put a bracket around it with the charge in the upper right hand corner
- Sun Oct 27, 2019 9:40 pm
- Forum: Trends in The Periodic Table
- Topic: Homework #4
- Replies: 5
- Views: 235
Re: Homework #4
We haven't learned anything about chemical bonds so I think it's safe to go with quantum world problems still.
- Sun Oct 27, 2019 9:39 pm
- Forum: Trends in The Periodic Table
- Topic: bond length
- Replies: 9
- Views: 463
Re: bond length
I don't think we have to know the exact measurements but a good thing to keep in mind is that in resonance structures, the actual molecule is a blend of all possible structures.
- Sun Oct 27, 2019 9:38 pm
- Forum: Trends in The Periodic Table
- Topic: Exceptions in the trends
- Replies: 4
- Views: 318
Re: Exceptions in the trends
This isn't a trend but I think a good exceptions to remember when doing electron configuration are chromium, copper, molybdenum and silver such that a half or full d orbital is more stable than being partially filled, so an electron from the 4s/5s orbitals rise to a 3d/4d orbital.
- Sun Oct 27, 2019 9:19 pm
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity
- Replies: 6
- Views: 336
Re: Electron Affinity
A negative electron affinity signifies a release of energy (exothermic reaction) and a positive electron affinity means more energy is needed than gained when adding the electron.
- Sun Oct 27, 2019 9:17 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy
- Replies: 9
- Views: 427
Re: Ionization Energy
Ionization energy is always positive because you have to add energy to remove an electron (an endothermic process).
- Sun Oct 27, 2019 9:14 pm
- Forum: Trends in The Periodic Table
- Topic: s block metals vs p block metals
- Replies: 2
- Views: 149
Re: s block metals vs p block metals
Yes. Due to their lower ionization energies, the s block elements are able to give up electrons more easily thus forming cations which makes them more reactive.
- Sun Oct 20, 2019 9:17 pm
- Forum: Properties of Light
- Topic: Where to find equations?
- Replies: 5
- Views: 203
Re: Where to find equations?
There is an equation sheet on Dr. Lavelle's website. If there aren't any on that sheet that we learned in class, it's a good idea to take note of them and memorize/get a good understanding of the equation because it's probably important.
- Sun Oct 20, 2019 9:15 pm
- Forum: Properties of Light
- Topic: Midterm Exam
- Replies: 21
- Views: 734
Re: Midterm Exam
On that note, does anyone know which topics will be covered which weeks? I expected to see weeks on the syllabus next to each new topic, but didn't notice anything like that. I didn't see a calendar or anything. I think there should be a week or at least a couple days to review everything (which is...
- Sun Oct 20, 2019 9:09 pm
- Forum: Properties of Light
- Topic: Equations and Constants
- Replies: 6
- Views: 279
Re: Equations and Constants
I think it's good to memorize the important equations like E=hv or c = lambda(v) because they are used together a lot. We should be learning more that are just good to memorize even though they might be provided because it will show you have an understanding of the concept and you can save time on t...
- Sun Oct 20, 2019 9:05 pm
- Forum: Properties of Light
- Topic: light
- Replies: 5
- Views: 269
Re: light
Yep. Dr. Lavelle was using this as an example to disprove something in class!
- Sun Oct 20, 2019 9:04 pm
- Forum: Properties of Light
- Topic: N levels
- Replies: 8
- Views: 507
Re: N levels
n-levels are energy levels that electrons can jump to are fall from. Jumping energy levels requires energy to be put into the electron (exciting it) and electrons that fall from higher energy levels to lower emit energy to get back to their ground state.
- Sun Oct 20, 2019 8:54 pm
- Forum: Properties of Light
- Topic: 1A.9 Energy of Photon
- Replies: 12
- Views: 513
Re: 1A.9 Energy of Photon
E = hv --> E is the energy of the photon and you get it by multiplying Planck's constant (h) and the frequency (v)
- Sun Oct 20, 2019 8:51 pm
- Forum: Properties of Light
- Topic: What are the units of hertz
- Replies: 41
- Views: 2227
Re: What are the units of hertz
cycle per second (s-1)
- Sun Oct 20, 2019 8:49 pm
- Forum: Properties of Light
- Topic: Next test
- Replies: 23
- Views: 1117
Re: Next test
Yes I think we always get an equation sheet
- Sun Oct 20, 2019 8:47 pm
- Forum: Properties of Light
- Topic: Unit for Wavelength
- Replies: 34
- Views: 2554
Re: Unit for Wavelength
Wavelength is measured in meters but always keep in mind the conversions! Typically the problems that I've seen for wavelength call for answers in nanometers.
- Sat Oct 12, 2019 6:20 pm
- Forum: Properties of Light
- Topic: Frequency vs. Wavelength
- Replies: 15
- Views: 724
Re: Frequency vs. Wavelength
frequency and wavelength are inversely related
- Sat Oct 12, 2019 3:12 pm
- Forum: Properties of Light
- Topic: Light Intensity
- Replies: 6
- Views: 206
Re: Light Intensity
Sounds good! Remember to consider light as photons, or packets of energy where one photon interacts with one electron. High intensity light with long wavelengths and low frequency wouldn't be able to eject electrons; therefore, it really depends on the energy of the photon and not the intensity of t...
- Sat Oct 12, 2019 3:02 pm
- Forum: Significant Figures
- Topic: How many significant figures are in 7.00 x 10^2?
- Replies: 25
- Views: 3653
Re: How many significant figures are in 7.00 x 10^2?
There would be 3 sigfigs in 7.00 x 10^2. Despite it being 700, the notation matters. Therefore if your answer was 700 but you needed to make it 2 sigfigs, you would put your answer as 7.00x10^2.
- Sat Oct 12, 2019 2:55 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test 1 [ENDORSED]
- Replies: 107
- Views: 27661
Re: Test 1 [ENDORSED]
curry 1E wrote:Can someone explain what Angstroms are? I was confused on the test on this question.
Angstrom conversions are given on the test. It's significant to know because bond lengths are typically measured in Angstroms.
- Sat Oct 12, 2019 2:52 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test 1 [ENDORSED]
- Replies: 107
- Views: 27661
Re: Test 1 [ENDORSED]
pauline 1L wrote:Does anyone know where and when our grades for this class will be updated?
I believe our TAs will be handing them back during the next discussion!
- Sun Oct 06, 2019 12:00 am
- Forum: SI Units, Unit Conversions
- Topic: Polyatomic ions
- Replies: 3
- Views: 183
Re: Polyatomic ions
I memorized them really fast using quizlet! My old chem teacher recommended pairing "-ate" and "-ic" and thinking of it as "ate it" and "-ite" and "-ous" as "bronch-itis".
- Sat Oct 05, 2019 11:57 pm
- Forum: SI Units, Unit Conversions
- Topic: SI
- Replies: 5
- Views: 250
Re: SI
I think you should memorize them all just in case. It's not too difficult as you should probably memorize them for upcoming courses and labs as well
- Sat Oct 05, 2019 11:56 pm
- Forum: SI Units, Unit Conversions
- Topic: Homework
- Replies: 9
- Views: 520
Re: Homework
You can do either. Pencil is probably recommended as pen can get messy if you make mistakes
- Sat Oct 05, 2019 11:55 pm
- Forum: SI Units, Unit Conversions
- Topic: When is Test #1?
- Replies: 9
- Views: 545
Re: When is Test #1?
Test is in your upcoming discussion section! Good luck studying :)
- Sat Oct 05, 2019 11:53 pm
- Forum: SI Units, Unit Conversions
- Topic: Temperature
- Replies: 6
- Views: 383
Re: Temperature
You can technically get Fahrenheit from Kelvin too through Celsius, but it's more common to see Celsius and Kelvin in chemistry. As said by the person above, they're linked by magnitude (Kelvin is Celsius + 273.15).