Search found 30 matches
- Wed Jun 06, 2018 2:43 am
- Forum: Lewis Acids & Bases
- Topic: Weak vs strong acids [ENDORSED]
- Replies: 7
- Views: 1039
Re: Weak vs strong acids [ENDORSED]
I think a way to tell weak acids from strong acids is by the bond strength. If the bond is weaker, it would be easier for the acid to donate the H + . The bond would also be easier to break if the resulting anion is stabler. You can also identify a weak acid if it's in the carboxyl group (Edit: orga...
- Wed Jun 06, 2018 2:24 am
- Forum: Conjugate Acids & Bases
- Topic: Conjugate acids/bases
- Replies: 1
- Views: 365
Re: Conjugate acids/bases
Basically, when a base accepts a proton (H + ) it forms a conjugate acid, and when an acid donates a proton (H + ) it forms a conjugate base. So to write a conjugate acid you add an H+ to the base, and to write a conjugate base you remove an H+ from the acid. e.g. The conjugate acid of O 2- is OH - ...
- Wed Jun 06, 2018 2:10 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Angles between bonds
- Replies: 2
- Views: 399
Re: Angles between bonds
Like what Isabelle said, a lone pair forms a region of e- density that repels more than bonded pairs. To achieve the least amount of repulsion, the rest of the bond angles become slightly smaller. Hope this helps!!
- Fri Jun 01, 2018 9:53 am
- Forum: Bond Lengths & Energies
- Topic: Test 3 bond length question
- Replies: 8
- Views: 1052
Re: Test 3 bond length question
Additionally, part of the question was a comparison of two double bonds, each with two lone pairs. In this scenario, how would you discover which of the two bond lengths was longer? * Also, is it correct in thinking the lone pairs stretch out the bond length? It basically still depends on the bond ...
- Mon May 28, 2018 2:49 am
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Meaning
- Replies: 5
- Views: 989
Re: Formal Charge Meaning
I think it also indicates the electron distribution within a molecule. :)
- Mon May 28, 2018 2:25 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: lone pairs
- Replies: 3
- Views: 438
Re: lone pairs
Lone pairs have greater repulsion than bonded pairs. To form a shape with least repulsion between atoms, the bond angles might become smaller when there's a lone pair than if it's bonded. Example: SF4 forms a seesaw shape. XeF4 has two lone pairs on Xe, so to form the shape with least repulsion, it ...
- Tue May 22, 2018 12:51 pm
- Forum: Lewis Structures
- Topic: OH Bonds
- Replies: 2
- Views: 358
Re: OH Bonds
I don't think they are automatically bond together, and it really depends on the formal charge and the octet rule. I'll attach some examples where they don't bond. Hope this helps!!
- Tue May 22, 2018 12:42 pm
- Forum: Lewis Structures
- Topic: Radical
- Replies: 3
- Views: 465
Re: Radical
I think it's determined by the lowest formal charge and not exceeding an octet that's not expanded.
- Tue May 22, 2018 12:39 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Trend for Polarizing Power of Cations and Anions
- Replies: 1
- Views: 1106
Re: Trend for Polarizing Power of Cations and Anions
Basically, polarizing power is the ability of the cation to distort the anion. It depends on the size of the cation: the smaller the cation, the closer its traction is to the anion. Polarizing power also increases when the cation is more positively charged. High polarizing power results in ionic bon...
- Thu May 17, 2018 11:59 am
- Forum: Lewis Structures
- Topic: Creating a Lewis Stucture
- Replies: 8
- Views: 1006
Re: Creating a Lewis Stucture
I don't think this was really covered in class, but for H2C(NH2)COOH, it has a carboxylic acid (R-COOH) and an amidogen (NH2-). That leaves the central atom with lowest ionization energy, which is carbon. The carbon goes in the middle, and NH2- and R-COOH go on both sides. Finally the two hydrogen g...
- Thu May 17, 2018 12:24 am
- Forum: Ionic & Covalent Bonds
- Topic: Formaldehyde Formula
- Replies: 2
- Views: 505
Re: Formaldehyde Formula
I'm not really sure about this, but it's probably that formaldehyde contains an aldehyde (R-CHO)? Hope this helps!:)
- Wed May 16, 2018 9:54 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarization and Solubiity
- Replies: 2
- Views: 691
Re: Polarization and Solubiity
In the silver halides example, increasing size of the anion leads to increasing covalent character of the silver halide (AgF, AgCl, AgBr, Agl).
Increasing size of anion -> more distorted anion -> less solutability.
Hope this helps!!
Increasing size of anion -> more distorted anion -> less solutability.
Hope this helps!!
- Sun May 13, 2018 10:50 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: FORMAL CHARGE
- Replies: 9
- Views: 953
Re: FORMAL CHARGE
Yes, I agree that the lone pairs are the dots surrounding that letter. If you subtract the valence electron by these lone pairs and 1/2 the bonding electrons, you get the formal charge. Hope this helps!
- Mon May 07, 2018 10:58 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: homework week 6
- Replies: 3
- Views: 542
Re: homework week 6
I think it's okay to turn in any of the problems covered so far and you haven't done yet since they are all covered by midterm. However, it might depend on your TA. Hope this helps!
- Mon May 07, 2018 10:54 pm
- Forum: Ionic & Covalent Bonds
- Topic: Resonance [ENDORSED]
- Replies: 5
- Views: 655
Re: Resonance [ENDORSED]
Resonance is indicated by double-headed arrows that connect different possible Lewis diagrams for one actual structure. The arrows compare and contrast those possible Lewis structures for a molecule. e.g., the actual structures of N-O in NO3 have a partial double bond character, but on the diagram, ...
- Wed May 02, 2018 8:54 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 2.21
- Replies: 2
- Views: 360
Re: 2.21
Yes, l is the orbital angular momentum number. In this case, you need to match s,p,d,f orbitals with their corresponding angular momentum number (l). Hope this helps!
- Tue May 01, 2018 4:24 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Energy levels and Orbitals
- Replies: 3
- Views: 553
Re: Energy levels and Orbitals
Hi, I believe what the series describe are Principle quantum numbers(n), or shells as it's usually called. Shells determine the energy levels. Angular momentum quantum number(l) describes the orbital/shape of the subshells (I=0,1,2,3 corresponding to s,p,d,f), and each shell can contain several subs...
- Mon Apr 30, 2018 4:33 pm
- Forum: DeBroglie Equation
- Topic: De Brogiles wavelength
- Replies: 4
- Views: 746
Re: De Brogiles wavelength
In addition to Sara's answer and pls correct me if I'm wrong:), since it's one atom of neon, the molar mass has to be converted using Avogadro's constant.
- Thu Apr 26, 2018 2:33 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3917591
Re: Post All Chemistry Jokes Here
playground duty :)
- Tue Apr 24, 2018 2:04 pm
- Forum: Properties of Light
- Topic: Diffraction Patterns
- Replies: 3
- Views: 819
Re: Diffraction Patterns
I believe the answer is D. From Dr. Lavelle's lecture last week, diffraction pattern is a combination of destructive and constructive waves that leads to specific patterns based on what is causing the diffraction. Constructive interference is "in phase", meaning the waves' peaks and trough...
- Mon Apr 23, 2018 4:10 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Homework Questions for Week IV
- Replies: 3
- Views: 419
Re: Homework Questions for Week IV
I believe the list of problems Dr. Lavelle sent us is only for review purposes; you can still choose from any problems covered in class so far within the outline files.
- Mon Apr 23, 2018 1:22 am
- Forum: Administrative Questions and Class Announcements
- Topic: Weekly Online Discussion Points
- Replies: 2
- Views: 466
Re: Weekly Online Discussion Points
I don't think we need to record it somewhere else, just make sure to post at least three per week haha.
- Mon Apr 23, 2018 1:17 am
- Forum: Administrative Questions and Class Announcements
- Topic: Test Time
- Replies: 6
- Views: 959
Re: Test Time
It was too short and I didn't manage to finish it, and most people I heard from didn't finish it as well. I think it might be supposed to be challenging with timing, but I sure need some more practice with timing to be honest.
- Wed Apr 18, 2018 3:10 pm
- Forum: DeBroglie Equation
- Topic: Measurable Wavelike Properties
- Replies: 2
- Views: 380
Re: Measurable Wavelike Properties
I believe what Dr Lavelle said was the wavelength needs to be no less than 10^-18 to be measurable.
- Sun Apr 15, 2018 7:44 pm
- Forum: SI Units, Unit Conversions
- Topic: Avogadro's Number [ENDORSED]
- Replies: 11
- Views: 1434
Re: Avogadro's Number [ENDORSED]
Yes, it can be used to convert from moles to molecules as well (1 mole= 6.022 × 10^23 molecules). I think it depends on the basic units of the substance; whether it's atoms or molecules.
- Wed Apr 11, 2018 11:06 am
- Forum: Molarity, Solutions, Dilutions
- Topic: Fundamentals problem G7
- Replies: 2
- Views: 215
Re: Fundamentals problem G7
Since this question is about the mass of KNO3 and H20 in the solution, I don't think we need to convert them to volumes. I believe "Describe how you would prepare the solution" refers to the actual steps it takes to prepare this solution in a laboratory. :)
- Tue Apr 10, 2018 6:08 pm
- Forum: SI Units, Unit Conversions
- Topic: L35, What is t? (Conversion)
- Replies: 3
- Views: 484
Re: L35, What is t? (Conversion)
Hi Maria, I believe t is ton, a non-SI unit that roughly equals to 1000 kilograms. I'm unsure about what will be on the test though.. anyway hope this helps! :)
- Mon Apr 09, 2018 10:15 pm
- Forum: SI Units, Unit Conversions
- Topic: Temperature
- Replies: 5
- Views: 753
Re: Temperature
In today's lecture we learned that Celsius is often used for measurements, and Kelvin is often used in calculation. One of the reasons is probably that Celsius and Kelvin have the same size of scale (K=C+273.15), making it easier to convert one of them to the other. :)
- Fri Apr 06, 2018 1:17 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Which mass of oxygen should be used? [ENDORSED]
- Replies: 23
- Views: 3389
Re: Which mass of oxygen should be used? [ENDORSED]
I remembered from class that it's better to aim for 3 digits after the decimal point (for significant figures), and it's definitely more precise to use 15.99 g/mol for oxygen. I don't think points will be taken off for this during exams, but I'm not totally certain about how much you can round up. H...
- Fri Apr 06, 2018 1:05 pm
- Forum: Significant Figures
- Topic: Sig Figs [ENDORSED]
- Replies: 9
- Views: 991
Re: Sig Figs [ENDORSED]
I agree with Anna. Also scientific notation can really come in handy sometimes for significant figures. :)
Hope this helps!
Hope this helps!