Search found 30 matches
- Sun Dec 09, 2018 3:49 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Size and Polarizability
- Replies: 4
- Views: 655
Re: Size and Polarizability
does left to right or up and down have a greater effect on radii?
- Sun Dec 09, 2018 3:39 pm
- Forum: Air Pollution & Acid Rain
- Topic: Acid Rain
- Replies: 24
- Views: 3802
Re: Acid Rain
Is acid rain formed from SO2 or SO4?
- Sun Dec 09, 2018 3:37 pm
- Forum: Naming
- Topic: order of ligand name
- Replies: 5
- Views: 690
Re: order of ligand name
They just go in alphabetical order, disregarding the prefixes.
- Sun Dec 02, 2018 3:06 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Dissociation energy
- Replies: 7
- Views: 610
Re: Dissociation energy
Dissociation energy is the energy required to break a bond. When bonds are formed, energy is released bc the molecule becomes more stable. When bonds are broken, energy must be added (positive) as to bring the atoms to less stable states (higher energy levels).
- Sun Dec 02, 2018 2:12 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Is Hydrogen Bonding a type of Dipole-Dipole Interaction?
- Replies: 5
- Views: 508
Re: Is Hydrogen Bonding a type of Dipole-Dipole Interaction?
If the final asks for the intermolecular forces in a molecule, can we always write that London forces are present or are there cases where they are not?
- Sun Dec 02, 2018 1:59 pm
- Forum: Hybridization
- Topic: lone pairs
- Replies: 20
- Views: 1982
Re: lone pairs
Is the answer automatically wrong if lone pairs are not separated from the shared pairs of electrons? for instance, if something has 3 shared pairs of electrons and 2 lone pairs, can it only be written as AX3E2 or can you write it as AX5? The VSEPR formula calls to use A for the central atom, X for...
- Sun Nov 25, 2018 5:39 pm
- Forum: Sigma & Pi Bonds
- Topic: Delta Bonds
- Replies: 4
- Views: 381
Re: Delta Bonds
What is an example of a compound that has a delta bond?
- Sun Nov 25, 2018 5:31 pm
- Forum: Resonance Structures
- Topic: Drawing resonance
- Replies: 17
- Views: 1814
Re: Drawing resonance
It is important to draw the resonance for a molecule because it demonstrates that the actual bond lengths are the average of the bond lengths. Do we need to include something to show the bond lengths are an average and the same or is that implied when we draw the resonance structures? I don't think...
- Sun Nov 25, 2018 5:26 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Energy of Interactions
- Replies: 4
- Views: 387
Re: Energy of Interactions
Imelda Mena 3I wrote:Does anyone know if the different types of bonds will be on test 3? Thanks in advance!
I think so. The syllabus says that test 3 will cover section 3.12 in the end of bonding and all of Molecular Shape and Structure.
- Sun Nov 18, 2018 11:17 pm
- Forum: Resonance Structures
- Topic: Drawing resonance
- Replies: 17
- Views: 1814
Re: Drawing resonance
It is important to draw the resonance for a molecule because it demonstrates that the actual bond lengths are the average of the bond lengths.
- Sun Nov 18, 2018 11:04 pm
- Forum: Dipole Moments
- Topic: Polar vs. Nonpolar
- Replies: 5
- Views: 444
Re: Polar vs. Nonpolar
If dipole moments, caused by differences in electronegativity, do not cancel, then the molecule will be polar. The atom with the greater electronegativity will get the delta negative and the atom with the lower electronegativity will have the delta positive. Electronegativity follows the general tre...
- Sun Nov 18, 2018 6:10 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: molecular shapes
- Replies: 13
- Views: 921
Re: molecular shapes
I don't think Dr. Lavelle has mentioned the trigonal pyramidal shape, but it is the answer to question 4.7 in the 6th edition. It also says that the bond angles are 109.5 degrees (which is the same angle as a tetrahedral shape) so are these two shapes the same? The trigonal pyramidal I think is the...
- Sun Nov 11, 2018 8:43 pm
- Forum: Dipole Moments
- Topic: Dipole
- Replies: 8
- Views: 742
Re: Dipole
Dipoles do not have much influence over Lewis structures, they are only important in VSEPR models.
- Sun Nov 11, 2018 8:36 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Molar Mass
- Replies: 8
- Views: 1272
Re: Molar Mass
To find the mass of a molecule however, you need to take the molar mass, found under the atomic symbol on the periodic table, and divide by Avogadro's number, 6.022X10^23.
- Sun Nov 11, 2018 8:28 pm
- Forum: Balancing Chemical Reactions
- Topic: Combustion Equation
- Replies: 21
- Views: 2710
Re: Combustion Equation
The reaction for combustion will be compound + O2 --> CO2 + H2O
- Sun Nov 04, 2018 10:25 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Ms quantum number relevancy on the midterm
- Replies: 4
- Views: 465
Re: Ms quantum number relevancy on the midterm
This is also important in questions asking a question similar to: how many electrons can have quantum numbers n=4, l=1? Because each configuration of n,l,m can have 2 possible Ms values.
- Sun Nov 04, 2018 10:13 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge and Lewis Structures
- Replies: 5
- Views: 612
Re: Formal Charge and Lewis Structures
The formal charges could be useful in determining the most favorable arrangement of atoms in a molecule, and therefore the most likely Lewis structure. The Lewis structure with formal charges closest to zero is, typically, most likely because it usually represents the lowest-energy arrangement of at...
- Sun Nov 04, 2018 9:40 pm
- Forum: Dipole Moments
- Topic: london forces
- Replies: 7
- Views: 821
Re: london forces
Yes, London forces are "universal" because they act between all molecules. They are the only interactions between non-polar molecules. The strength of the London forces typically increases as molar mass increases.
- Sun Oct 28, 2018 8:22 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Bonds
- Replies: 7
- Views: 672
Re: Covalent Bonds
Non-metals typically have high electronegativity. They acquire electrons to fill their valence shell and, therefore, they form anions.
- Sun Oct 28, 2018 7:53 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy and Electron Affinity
- Replies: 9
- Views: 1805
Re: Ionization Energy and Electron Affinity
Is there a trend for electron affinities?
- Sun Oct 28, 2018 7:42 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy [ENDORSED]
- Replies: 7
- Views: 875
Re: Ionization Energy [ENDORSED]
Ionic radii decreases across a period (from left to right on the period table). The closer an electron is to the nucleus, the more difficult it will be to remove, therefore requiring a greater ionization energy.
- Sun Oct 21, 2018 9:02 pm
- Forum: Properties of Electrons
- Topic: Questions about the energy level [ENDORSED]
- Replies: 3
- Views: 435
Re: Questions about the energy level [ENDORSED]
To think this through the relation of energy and wavelength formulaically, consider the formula: wavelength = hc/E. Because h and c are both constants, the numerator will always equal the product of Planck's constant and the speed of light. Wavelength will therefore decrease as energy, E, increases....
- Sun Oct 21, 2018 7:26 pm
- Forum: Properties of Electrons
- Topic: Wavelength Calculations
- Replies: 5
- Views: 616
Re: Wavelength Calculations
Will all constants be provided on the test?
- Sun Oct 21, 2018 7:17 pm
- Forum: Photoelectric Effect
- Topic: Kinetic energy
- Replies: 4
- Views: 315
Re: Kinetic energy
The work function (Ф) is the energy required to remove an electron from a metal. If the energy of the photon, represented by hv, is greater than the work function, the electron is ejected with kinetic energy (1/2 me x v^2) equaling the difference in the energy supplied by the photon and the work fun...
- Sun Oct 14, 2018 10:17 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing reactions tips
- Replies: 29
- Views: 2039
Re: Balancing reactions tips
I have found it is easiest to balance the least occurring elements first, starting in compounds consisting of the most elements. Then, I leave compounds such as O2 for last because it is easy to balance the lone element of oxygen according to what the rest of the equation calls for.
- Sun Oct 14, 2018 10:04 pm
- Forum: SI Units, Unit Conversions
- Topic: Homework for Week 2
- Replies: 16
- Views: 985
Re: Homework for Week 2
For week 3 homework, do we have to answer questions from a specific outline?
- Sun Oct 14, 2018 9:41 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Formula M1V1=M2V2 [ENDORSED]
- Replies: 5
- Views: 6452
Re: Formula M1V1=M2V2 [ENDORSED]
This formula is especially useful in diluting stock solutions.
- Sun Oct 07, 2018 11:04 pm
- Forum: Limiting Reactant Calculations
- Topic: Actual yield [ENDORSED]
- Replies: 4
- Views: 391
Re: Actual yield [ENDORSED]
Actual yield will always be less than theoretical yield due to side reactions, impurities, etc.
Percent yield = (Actual yield/theoretical yield) x100
Percent yield = (Actual yield/theoretical yield) x100
- Sun Oct 07, 2018 10:42 pm
- Forum: Significant Figures
- Topic: knowing how many sig figs to use
- Replies: 17
- Views: 2090
Re: knowing how many sig figs to use
For problems involving multiplication/division, the product/quotient should be rounded to the least number of sig figs of the factors. For problems involving addition/subtraction, the sum/difference should be rounded to the least number of sig figs after the decimal.
- Sun Oct 07, 2018 10:27 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: MOLARITY
- Replies: 17
- Views: 2048
Re: MOLARITY
With regards to molarity when diluting a solution, it is important to remember that the moles of solute remain the same. The unknown volume or mass can be computed by plugging known values into: M(initial)xV(initial) = M(final)xV(final)