Search found 31 matches
- Sun Jun 10, 2018 9:48 pm
- Forum: Bronsted Acids & Bases
- Topic: Oxoacids
- Replies: 4
- Views: 627
Re: Oxoacids
Oxoacids more readily lose H+ if resulting anion is stabilized by electron withdrawing atoms which delocalize and stabilize the negative charge.
- Sun Jun 10, 2018 9:42 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Strength of an acid
- Replies: 14
- Views: 1703
Re: Strength of an acid
As you go down the group of the periodic table, acidity increases with the decrease of electronegativity (since the size of the atom increases). The smaller the atom, the shorter the bond and thus harder for them to dissociate in water. In my notes from class it says that HF<HCl<HBr<HI which goes fr...
- Sun Jun 10, 2018 9:28 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Strong or weak acids/ bases
- Replies: 6
- Views: 2074
Re: Strong or weak acids/ bases
Most acids are weak acids that dissociates incompletely. These acids have higher pKa than strong acids which release all there H+ when dissolved in water. Likewise, a weak base is a base that does not ionize fully in water and also has a lower pH compared to strong bases.
- Sun Jun 10, 2018 9:21 pm
- Forum: Lewis Acids & Bases
- Topic: Strong Acids
- Replies: 4
- Views: 621
Re: Strong Acids
In my notes I have HF,HCl<HBr<HI. (less acidic to more acidic)
- Sun Jun 10, 2018 9:19 pm
- Forum: Lewis Acids & Bases
- Topic: Weak vs strong acids [ENDORSED]
- Replies: 7
- Views: 1038
Re: Weak vs strong acids [ENDORSED]
The strength of an acid determines its ability or tendency to lose a H+. A strong acid completes ionizes in a solution while a weak acid only partially dissociates. Stronger acids have a smaller pKa.
- Sun Jun 03, 2018 5:15 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone pairs
- Replies: 7
- Views: 818
Re: Lone pairs
Bonding pairs take up less space because they are farther away from the central atom and is controlled by the sharing atoms, while a lone pair is closer to the nucleus and repels more strongly.
- Sun Jun 03, 2018 5:08 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Transition Metal Valence Electrons
- Replies: 3
- Views: 511
Re: Transition Metal Valence Electrons
It usually helps to draw out the electron configuration diagram. For example, for Ti, its electron configuration is [Ar]4s^2 3d^2 so it would make sense for it to have 4 valence electrons from the outermost 4s electrons and the 3d electrons.
- Sun Jun 03, 2018 4:59 pm
- Forum: Hybridization
- Topic: strength of sigma and pi bonds
- Replies: 10
- Views: 1312
Re: strength of sigma and pi bonds
Yes, a sigma bond is stronger than a pi bond. This is because the length of a sigma bond is shorter than a pi bond, and it takes more energy to break a sigma bond.
- Sun May 27, 2018 8:09 pm
- Forum: Resonance Structures
- Topic: ranking
- Replies: 11
- Views: 1531
Re: ranking
A resonance structure has a greater importance if it fulfills the octet rule and if it has minimum charge separation. In addition, there should be no like charges on atoms that are next to each other.
- Sun May 27, 2018 8:05 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizing power
- Replies: 10
- Views: 8764
Re: Polarizing power
The ability of a cation to distort an anion (or pull an electron away) is known as the polarizing power.
- Sun May 27, 2018 7:55 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Resonance
- Replies: 7
- Views: 1002
Re: Resonance
Delocalization is when electric charge is spread over more than one atom. If there are delocalized electrons, it increases the stability of the system compared to a similar system where electrons are localized.
- Mon May 21, 2018 1:26 am
- Forum: Electronegativity
- Topic: Electronegativiry vs electron affinity [ENDORSED]
- Replies: 4
- Views: 983
Re: Electronegativiry vs electron affinity [ENDORSED]
The trends are basically the same, and the trend increases as you go across a period and up a group. Electronegativity is how likely the atom will attract electrons, while electron affinity is the amount of energy released when an electron is added to the atom.
- Mon May 21, 2018 1:23 am
- Forum: Ionic & Covalent Bonds
- Topic: Ionic versus Covalent Bonds [ENDORSED]
- Replies: 1
- Views: 282
Re: Ionic versus Covalent Bonds [ENDORSED]
Yes, for example, a molecule like NaOH. The Na+ ion is ionically bonded to the OH- ion, but for the OH- ion, the oxygen and hydrogen atoms are covalently bonded together.
- Mon May 21, 2018 1:21 am
- Forum: Lewis Structures
- Topic: Lewis Structure
- Replies: 2
- Views: 350
Re: Lewis Structure
I'm not sure if I understood your question correctly, but yes, there can be two pairs of elements sharing a bond in a linear structure like the previous poster said.
- Sun May 13, 2018 11:18 pm
- Forum: Trends in The Periodic Table
- Topic: electron affinity [ENDORSED]
- Replies: 15
- Views: 2038
Re: electron affinity [ENDORSED]
A lower electron affinity indicates that an atom does not accept electrons as easily.
- Sun May 13, 2018 11:10 pm
- Forum: Octet Exceptions
- Topic: OCTET RULE [ENDORSED]
- Replies: 10
- Views: 1097
Re: OCTET RULE [ENDORSED]
Octet rule means that when atoms combine to form molecules, they each lose, gain, or share valence electrons until they attain/share eight electrons.
- Sun May 06, 2018 9:37 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions for electron configuration
- Replies: 3
- Views: 473
Re: Exceptions for electron configuration
For chromium and copper, a completely full or half full d-sublevel is more stable than a partially filled d sub-level, so an electron from the 4s orbital is excited and rises to the 3d orbital.
- Sun May 06, 2018 9:30 pm
- Forum: Trends in The Periodic Table
- Topic: Trends to Know
- Replies: 12
- Views: 1381
Re: Trends to Know
I think you should know how electron affinity increases from left to right within a period (caused by the decrease in atomic radius) and how electron affinity decreases from top to bottom within a group (caused by the increase in atomic radius).
- Sun May 06, 2018 9:25 pm
- Forum: Properties of Light
- Topic: The visible spectrum
- Replies: 4
- Views: 732
Re: The visible spectrum
The main difference between them is that continuous spectrum contains no gaps whereas line spectrum contains many gaps.
- Sun Apr 29, 2018 9:27 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Unpaired Electrons [ENDORSED]
- Replies: 7
- Views: 1109
Re: Unpaired Electrons [ENDORSED]
FInd the elctron configuration first then draw the valence orbitals so you can look for the unpaired electrons.
- Sun Apr 29, 2018 9:22 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: The concept of Orbitals
- Replies: 12
- Views: 1105
Re: The concept of Orbitals
Orbitals are region of space around the nucleus where we can find electrons with the largest probability.
- Sun Apr 29, 2018 9:13 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: How to properly format your answers
- Replies: 6
- Views: 664
Re: How to properly format your answers
I think Professer Lavelle used half arrows!
- Sun Apr 22, 2018 7:46 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect
- Replies: 12
- Views: 1146
Re: Photoelectric Effect
Yes, the energy of the photon has to overcome the threshhold energy, and any energy of the photon that is left over is converted to kinetic energy of the electron.
- Sun Apr 22, 2018 7:26 pm
- Forum: Empirical & Molecular Formulas
- Topic: Rounding atomic weight (general question) [ENDORSED]
- Replies: 8
- Views: 1091
Re: Rounding atomic weight (general question) [ENDORSED]
I would use the atomic mass on the periodic table he gives us, and round at the end.
- Sun Apr 22, 2018 7:18 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Units - L or mL? [ENDORSED]
- Replies: 15
- Views: 4786
Re: Units - L or mL? [ENDORSED]
Unless the question specifies otherwise, I would do liters
- Sun Apr 15, 2018 9:19 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: What do the coefficients/subscripts represent [ENDORSED]
- Replies: 7
- Views: 1561
Re: What do the coefficients/subscripts represent [ENDORSED]
4 molecules of H20 has 8 atoms of hydrogen total
- Sun Apr 15, 2018 9:16 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Molarity [ENDORSED]
- Replies: 3
- Views: 514
Re: Molarity [ENDORSED]
Assuming equal volume, technically yes. But, the different is negligible.
- Sun Apr 15, 2018 9:10 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Using the uncertainty principle [ENDORSED]
- Replies: 2
- Views: 431
Re: Using the uncertainty principle [ENDORSED]
Its' not h. It's h bar which is the same thing as h/2pi
- Sun Apr 15, 2018 9:01 pm
- Forum: Empirical & Molecular Formulas
- Topic: Finding Empirical and Molecular Formula [ENDORSED]
- Replies: 6
- Views: 988
Re: Finding Empirical and Molecular Formula [ENDORSED]
Count the atoms to get the molecular formula. The empricial formula is the simplified ratio!
- Sun Apr 15, 2018 8:57 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing Chemical Reactions
- Replies: 5
- Views: 481
Re: Balancing Chemical Reactions
I usually look for an element that appears only once on both sides of the equation and balance that first :) Make sure the amount of different elements on both sides are equal. But it also might help to balance the polyatomic molecules first!
- Sun Apr 15, 2018 8:49 pm
- Forum: DeBroglie Equation
- Topic: 1.41 [ENDORSED]
- Replies: 3
- Views: 582
Re: 1.41 [ENDORSED]
yes, use the de brogile's equation (lambda = h/mv). solve for v the velocity, because you were given the wavelength (lambda= 100picometers) in the problem , and both h (plancks constant) and m (mass of neutron) are constants. :)