Search found 55 matches
- Sun Jul 28, 2019 4:17 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: Nitrogen as a Base
- Replies: 6
- Views: 1233
Re: Nitrogen as a Base
Well, the answer is in your question. My guess would be because N has the lone pair, which can be donated to another atom, which is the definition of a Lewis base.
- Sun Jul 28, 2019 4:01 pm
- Forum: Bond Lengths & Energies
- Topic: Strength of bonds
- Replies: 1
- Views: 319
Re: Strength of bonds
I remember Lavelle said in lecture that the number of valence electrons is prioritized over the size of the electron when it comes to the strength of bonds.
- Sun Jul 28, 2019 4:00 pm
- Forum: Conjugate Acids & Bases
- Topic: 6a1(b)
- Replies: 1
- Views: 656
Re: 6a1(b)
Well, NH2NH2 is one compound. To understand it more, it can be written as N2H4. Using the Bronsted definition, you would know that because N2H4 is a base, it receives an H+ ion from H2O. It wouldn't receive two since NH2NH2 is one compound. So the conjugate acid would be NH3NH2.
- Wed Jul 24, 2019 8:24 pm
- Forum: Naming
- Topic: Homework 9C3(a)
- Replies: 2
- Views: 460
Re: Homework 9C3(a)
Can someone walk me through step by step how to write the formula for the following compound: potassium hexacyanidochromate(III) I understand that the K goes first for potassium because it is a cation, and is outside the brackets because it is a separate word. I understand "hexacyanido" m...
- Tue Jul 23, 2019 8:25 pm
- Forum: Ionic & Covalent Bonds
- Topic: Xenon -- why is it the only noble gas that can form bonds?
- Replies: 4
- Views: 4380
Re: Xenon -- why is it the only noble gas that can form bonds?
I could be wrong, but from my understanding, Xe has a larger atomic radius compared to the other noble gases above the element. I wondered why Radon couldn't form bonds despite the large radius like Xenon, but because Radon is radioactive, that would mean that the element is unstable and would be un...
- Tue Jul 23, 2019 8:18 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ASHLEY'S STEP UP WORKSHEETS
- Replies: 15
- Views: 1587
Re: ASHLEY'S STEP UP WORKSHEETS
Chem_Mod wrote:Step up worksheet for this Monday
Question: For 1b, is there supposed to be a charge because I'm having trouble drawing the structure of CH2F as being neutral. Or is the molecule a radical?
- Tue Jul 23, 2019 4:30 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2763904
Re: Post All Chemistry Jokes Here
A gold atom went to a bar, and the bartender said, "Au, get out of here."
- Tue Jul 23, 2019 11:49 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: Test 2
- Replies: 1
- Views: 457
Test 2
So, I got a question on test 2 wrong regarding the calculation of the maximum number of H-bonds DNA(specifically the adenine and thymine base) can form with water molecules. Whoever got this question right or understands it now, how do you go about solving this question?
- Mon Jul 22, 2019 10:28 pm
- Forum: Naming
- Topic: 9C.1 part c
- Replies: 4
- Views: 1138
Re: 9C.1 part c
Oh!!! I figured it out. If the coordinate complex has a negative net charge, you add the -ate. That makes sense now.
- Mon Jul 22, 2019 10:10 pm
- Forum: Naming
- Topic: 9C.1 part c
- Replies: 4
- Views: 1138
9C.1 part c
So, the ion in question is [Co(CN)5(OH2)]2-. I know how to get the oxidation number, but I don't get why in this case you add an -ate to the end of cobalt when naming the ion. Is it because of the water?
- Mon Jul 22, 2019 10:26 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Oxidation state [ENDORSED]
- Replies: 3
- Views: 733
Re: Oxidation state [ENDORSED]
So, on 9C.1 part a, I don't get how to find the change in ligands. So, I know to find the oxidation number of a metal, you use the equation (# of metals)(oxidation # of metal) + [sum of (number of ligands)(change in ligands)]= ion charge. With the hexacyanoferrate (II) ion, (Fe(CN)6)4-, I know ther...
- Mon Jul 22, 2019 9:46 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Oxidation state [ENDORSED]
- Replies: 3
- Views: 733
Re: Oxidation state [ENDORSED]
So, on 9C.1 part a, I don't get how to find the change in ligands. So, I know to find the oxidation number of a metal, you use the equation (# of metals)(oxidation # of metal) + [sum of (number of ligands)(change in ligands)]= ion charge. With the hexacyanoferrate (II) ion, (Fe(CN)6)4-, I know there...
- Mon Jul 22, 2019 12:35 am
- Forum: Ionic & Covalent Bonds
- Topic: Polarizing Power [ENDORSED]
- Replies: 2
- Views: 544
Re: polarity power [ENDORSED]
I hope this explanation helps. So, I believe this question is related to polarizing power. So, the cations that tend to have high polarizing power are the cations that have electrons concentrated near the nucleus(so the upper periods). With Mg2+, the cation will satisfy an octet with electrons conce...
- Wed Jul 17, 2019 10:56 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ASHLEY'S STEP UP WORKSHEETS
- Replies: 15
- Views: 1587
Re: ASHLEY'S STEP UP WORKSHEETS
Chem_Mod wrote:Answers to the last worksheet
Question: On 2c, wouldn't the answer be CO2 since there is a larger electronegativity difference. Because you said CS2 has more covalent character when the questions asks for a greater ionic character.
- Wed Jul 17, 2019 10:51 pm
- Forum: Lewis Structures
- Topic: Problem 2B3 7th Edition
- Replies: 2
- Views: 546
Re: Problem 2B3 7th Edition
So, we need to consider that this compound has a net charge of 0. When doing the Lewis structure, it would only make sense to give Si two double bonds to both O atoms since giving those Oxygens a double bond will make their formal charge 0. As to the electrons not being drawn on the Oxygens, I don't...
- Wed Jul 17, 2019 4:23 pm
- Forum: Lewis Structures
- Topic: Lewis Structures for Ions
- Replies: 1
- Views: 422
Re: Lewis Structures for Ions
The brackets are not used to indicate the number of added electrons per say, but the net charge of the compound, in this case -1. So, when drawing the Lewis structure, you should have a triple bond between Carbon and Nitrogen. Then, you put one lone pair on each atom. This is where formal charge com...
- Tue Jul 16, 2019 11:05 pm
- Forum: Ionic & Covalent Bonds
- Topic: Order of electron loss in ion formation
- Replies: 4
- Views: 691
Re: Order of electron loss in ion formation
That would be correct, you remove electrons from the right-most side of the configuration or add them at the right-most side. I don't think there's any exceptions.
- Tue Jul 16, 2019 11:04 pm
- Forum: Ionic & Covalent Bonds
- Topic: 3.11 6th Edition
- Replies: 2
- Views: 596
Re: 3.11 6th Edition
So, the question gives us the ground electron configurations of the ions. That means to get the original atom, we would need to add 3 electrons since these are M3 metals. Metals are typically cations, so that explains the plus 3. Part a, you add 3 electrons and get [Ar]3d^7 4s^2, which is Cobalt. Th...
- Tue Jul 16, 2019 6:03 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: midterm
- Replies: 1
- Views: 424
Re: midterm
Well, the electron configuration of Cu is [Ar] 3d^10 4s^1. So, Cu+ would be [Ar]3d^10 since you're taking away an electron. The principle quantum number would be n=3 since that's the coefficient of the d-orbital, and the angular quantum number would be l=2 since n-1 is equal to 2. Also, when l=2, an...
- Tue Jul 16, 2019 11:59 am
- Forum: Student Social/Study Group
- Topic: Study Group
- Replies: 2
- Views: 585
Re: Study Group
If you want to be in the study group, email me at jjoseph20@g.ucla.edu .
- Mon Jul 15, 2019 11:01 pm
- Forum: Dipole Moments
- Topic: Effect of size [ENDORSED]
- Replies: 7
- Views: 1360
Re: Effect of size [ENDORSED]
I believe this is due to the fact that with increasing molar mass and atomic size comes with an increase in electrons. With the increase in electrons, the atom has a higher interaction potential energy. Also, polarizability , which is the measure of the ability for anions to form dipoles or to be di...
- Sun Jul 14, 2019 10:34 pm
- Forum: Ionic & Covalent Bonds
- Topic: Difference Between Ionic and Covalent
- Replies: 8
- Views: 979
Re: Difference Between Ionic and Covalent
To add on, ionic bonds form lattices(salts) as products that tend to be soluble in water while covalent bonds form molecules that are less soluble in water.
- Sun Jul 14, 2019 10:32 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Bonds [ENDORSED]
- Replies: 3
- Views: 770
Re: Covalent Bonds [ENDORSED]
Well, the difference between the two would be that covalent bonds are the sharing of electrons between nonmetals; whether polar or non polar. Polar covalent bonds have to do with a lack of symmetrical distribution of electrons in the bond. As a result, the molecule formed from the polar covalent bon...
- Thu Jul 11, 2019 3:40 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron configuration
- Replies: 3
- Views: 661
Re: Electron configuration
I don't think we can do that. Although they're isoelectronic, they don't necessarily have the same properties because they have a different amount of protons. I believe you would go off of the previous noble gas, which is Neon, and then write the 3s orbital and 3p orbital. So, the configuration woul...
- Thu Jul 11, 2019 3:34 pm
- Forum: Resonance Structures
- Topic: Lewis Structures vs. Resonance
- Replies: 3
- Views: 585
Re: Lewis Structures vs. Resonance
Lewis structures are generally the form in which a molecules or compound's bonds can be displayed; whether that may be through covalent bonds or ionic bonds. The valence electrons are drawn with the elements in the compound and the bonds are noted using lines, one line per bond. There can be single,...
- Thu Jul 11, 2019 3:29 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Valence electrons
- Replies: 4
- Views: 632
Re: Valence electrons
From my understanding, Manganese (Mn) would have 7 valence electrons: 2 from the electrons in the 4s orbital and 5 from the 3d orbital. I don't think you count the previous orbitals when considering valence electrons since that's already substituted by the adjacent noble gas, which is Argon. Those e...
- Tue Jul 09, 2019 10:14 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Number of orbitals given quantum numbers
- Replies: 3
- Views: 547
Re: Number of orbitals given quantum numbers
Not sure if this will be a helpful explanation, but I'll try. So based on the principle quantum number, we know the element being discussed in the second row of the periodic table. This means that we're dealing with the s and p orbitals. So, we know that s has one orbital and p has 3 orbitals, equal...
- Tue Jul 09, 2019 9:38 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Test 1 number 7
- Replies: 4
- Views: 2673
Re: Test 1 number 7
So, I first converted the 225 mg. of cisplatin to grams and used the molar mass to convert the grams to moles of cisplatin. I then used the molarity= moles of solute/volume in liters equation to get the volume in liters I needed; plugging in the given molarity and the calculate moles of solute.
- Mon Jul 08, 2019 3:00 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ASHLEY'S STEP UP WORKSHEETS
- Replies: 15
- Views: 1587
Re: ASHLEY'S STEP UP WORKSHEETS
This was helpful. Thank you so much!
- Mon Jul 08, 2019 10:00 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Isoelectricty [ENDORSED]
- Replies: 1
- Views: 431
Re: Isoelectricty [ENDORSED]
Isoelectricity is a property that certain elements and ions share in regards to the amount of electrons they have. So, Na+ would be isoelectronic to Mg2+ or F- or Ne. Hope this helps.
- Mon Jul 08, 2019 9:56 am
- Forum: Properties of Light
- Topic: Light intensity [ENDORSED]
- Replies: 2
- Views: 515
Re: Light intensity [ENDORSED]
That is true. In order to manipulate the energy, you would need to use light of a different frequency since photons and electrons have a one photon one electron relationship. In doing so, a higher intensity(or an increase in photons) won't increase the energy of a light source to emit an electron.
- Mon Jul 08, 2019 9:53 am
- Forum: Properties of Electrons
- Topic: Electron Penetration
- Replies: 2
- Views: 649
Re: Electron Penetration
Additionally, the electrons in the s-state are of lower energy levels and are closer to the nucleus, so they are prone to penetrating the nucleus.
- Mon Jul 08, 2019 9:52 am
- Forum: Properties of Electrons
- Topic: Electron Penetration
- Replies: 2
- Views: 649
Re: Electron Penetration
I think the penetration refers to the attraction electrons in the s-state have towards the nucleus because of the opposite charges. However, that doesn't mean the electrons collapse into the nucleus since the change in velocity of an electron is greater than the speed of light.
- Sat Jul 06, 2019 12:40 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ASHLEY'S STEP UP WORKSHEETS
- Replies: 15
- Views: 1587
Re: ASHLEY'S STEP UP WORKSHEETS
Also, for the last question on the worksheet, shouldn't it be 10^15 since you're doing -18 - (-34)???? I got the other part of the answer, but is there an error with the exponent or is it just me?
- Sat Jul 06, 2019 12:15 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ASHLEY'S STEP UP WORKSHEETS
- Replies: 15
- Views: 1587
Re: ASHLEY'S STEP UP WORKSHEETS
Here are the answers for the first worksheet! I had a question on number 3 on this worksheet. So, I got up to getting 4.74 x10^39 s.^-1 mol. ^-1, but I don't know what to do from there. I attempted using stoichiometry to convert my units, but I don't know what to use to do that. Can someone help????
- Sat Jul 06, 2019 11:21 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 2A.5 part c
- Replies: 2
- Views: 567
Re: 2A.5 part c
But when I looked at the answer to that question, it was [Kr]4d^5.
- Fri Jul 05, 2019 8:17 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 2A.5 part c
- Replies: 2
- Views: 567
2A.5 part c
So, I don't get why the electron configuration for the ion Ga3+ has Kr instead of Ar. The answer is [Kr]4d^5, but I specifically don't get why there's the Krypton. Someone please explain!!!!!
- Thu Jul 04, 2019 11:02 am
- Forum: Balancing Chemical Reactions
- Topic: Balancing Equations
- Replies: 6
- Views: 749
Re: Balancing Equations
The strategies I use are to prioritize certain elements over others, specifically the ones with low amounts, such as carbon, nitrogen, etc. If you balance those first, you can, then, focus on the hydrogens and oxygen since that may involve larger stoichiometric coefficients. And for extra precaution...
- Wed Jul 03, 2019 4:18 pm
- Forum: Significant Figures
- Topic: Determining sig figs
- Replies: 10
- Views: 2328
Re: Determining sig figs
I have a question. So, if you are given a problem that has one value with 3 sig figs and another value of 4 sig figs, would you express your final answer using 3 or 4 sig figs? Would the amount of sig figs used change if there's more values given with 3 or 4 sig figs??? Sorry for asking.
- Tue Jul 02, 2019 8:18 pm
- Forum: General Science Questions
- Topic: Grading for the Course
- Replies: 4
- Views: 900
Re: Grading for the Course
This refers the posts that we make on this platform(chemistry community). It is 1 pt. per post for 6 pts. a week.
- Tue Jul 02, 2019 4:08 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: the equation of energy level
- Replies: 4
- Views: 621
Re: the equation of energy level
There is a negative sign present since you're decreasing energy levels to help excite an electron to be released. The electron is losing energy, so you wouldn't have a positive energy amount calculated if the electron energy is being lost. However, it's important to note that the equation mentioned ...
- Tue Jul 02, 2019 4:05 pm
- Forum: Photoelectric Effect
- Topic: kinetic energy of electron
- Replies: 8
- Views: 1098
Re: kinetic energy of electron
Well, there'd only be 0 kinetic energy for an electron when the energy of a photon is equal to the energy needed to remove an electron. So, refer to the E(photon)-E(work function)=E(excess). The excess energy is the kinetic energy. But the kinetic energy would be 0 when the photon's energy is at the...
- Mon Jul 01, 2019 2:23 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: 1.D.15 Seventh edition
- Replies: 2
- Views: 401
Re: 1.D.15 Seventh edition
Ok, that clears some things up. Thank you.
- Mon Jul 01, 2019 9:46 am
- Forum: Quantum Numbers and The H-Atom
- Topic: 1.D.15 Seventh edition
- Replies: 2
- Views: 401
1.D.15 Seventh edition
I know we haven't gone over this topic yet, but how would you calculate the principle momentum quantum number of an orbital. I know for an orbital angular momentum can be calculated using the square root(l(l+1) x (h)/2pi. For example, when given the orbital 6p, how would you calculate the principle ...
- Sat Jun 29, 2019 2:51 pm
- Forum: Properties of Light
- Topic: Frday's lecture
- Replies: 4
- Views: 494
Re: Frday's lecture
That's basically the reason. You substitute the v for the c/lambda, and because that's multiplied by h, you put them together to make E=hc/lambda. Then, if you want to solve for the wavelength, you cross multiply the equation, and divide both sides by e to get lambda=hc/e.
- Sat Jun 29, 2019 1:40 pm
- Forum: Photoelectric Effect
- Topic: Kinetic energy
- Replies: 11
- Views: 3242
Re: Kinetic energy
Nevermind, I figured it out. It's the mass of the electron, right?
- Sat Jun 29, 2019 12:13 pm
- Forum: Photoelectric Effect
- Topic: Kinetic energy
- Replies: 11
- Views: 3242
Re: Kinetic energy
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? A. 3.01 x 1025 J B. 3.98 x 10-19 J C. 7.96 x 10-19 J D. 1.99 x 10-19 J E. None of the above How would yo...
- Thu Jun 27, 2019 12:56 pm
- Forum: SI Units, Unit Conversions
- Topic: Properties
- Replies: 1
- Views: 436
Re: Properties
Extensive property is something that can be changed based on the amount of a substance. So, the volume can change based on the amount of mL or m.^3 of a substance you put in a container. An intensive property is something that doesn't change, so density. That is because no matter how much the volume...
- Thu Jun 27, 2019 12:53 pm
- Forum: Empirical & Molecular Formulas
- Topic: Formulas
- Replies: 10
- Views: 2231
Re: Formulas
In order to find the molecular formula, the actual molar mass of the substance must be given in the problem. If that's not given, you don't solve for the molecular formula. If so, divide that value, which should be g.mol^-1, by the molar mass computed by adding up the atomic weight of the elements i...
- Thu Jun 27, 2019 11:49 am
- Forum: Limiting Reactant Calculations
- Topic: M.25 seventh edition
- Replies: 1
- Views: 287
Re: M.25 seventh edition
Wait, never mind. I realized this is not part of the syllabus problems.
- Thu Jun 27, 2019 11:47 am
- Forum: Limiting Reactant Calculations
- Topic: M.25 seventh edition
- Replies: 1
- Views: 287
M.25 seventh edition
I came across this question and found that I had to calculate the percentage purity. Is that the same thing as percentage yield? If not, how would you go about solving this problem?
- Wed Jun 26, 2019 8:12 pm
- Forum: Significant Figures
- Topic: Determine Usage of Sig Figs During Problem
- Replies: 2
- Views: 476
Re: Determine Usage of Sig Figs During Problem
Someone can correct me if I'm wrong but yes, you would confirm the values you're using in the problem are 3 sig figs, in that scenario. So, you would round at the third place of the value. In this case, 15.999 would become 16. Hope this helps.
- Wed Jun 26, 2019 6:29 pm
- Forum: Limiting Reactant Calculations
- Topic: M.9 part a
- Replies: 3
- Views: 454
M.9 part a
Copper (II) Nitrate reacts with sodium hydroxide to produce precipitate of light blue copper (II) hydroxide. (a.) Write the net ionic equation for the reaction. I thought the answer for this part was Cu(NO3)2 + NaOH --> Cu(OH)2, but then I realized there's no Na in the product. Why is that and why i...
- Wed Jun 26, 2019 5:36 pm
- Forum: Balancing Chemical Reactions
- Topic: Combustion Equation
- Replies: 21
- Views: 2656
Re: Combustion Equation
Lauren Huang 1H wrote:Sometimes nitrogen can be an added reactant and product of the equation.
When would nitrogen be a product from a combustion reaction? Like, in what scenario?
- Tue Jun 25, 2019 4:13 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: G.5
- Replies: 3
- Views: 603
G.5
A student prepared a solution of Sodium carbonate by adding 2.111 g. of the solid to a 250.0-mL volumetric flask and adding water to the mark. Some of this solution was transferred to a buret. What volume of solution should the student transfer into a flask to obtain (a.) 2.15 mol Na+ ...? Can someo...