Search found 30 matches

by Jonathan Cheng 3C
Thu Dec 06, 2018 5:16 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Total Charge
Replies: 5
Views: 161

Re: Total Charge

You have to add up the charge of the transition metal and the charges of all the ligands attached to the transition metal
by Jonathan Cheng 3C
Thu Dec 06, 2018 5:08 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH formula?
Replies: 21
Views: 317

Re: pH formula?

pH = - log[H+] while pOH is either 14 - pH or -log[OH-]. We do not need to know how these formulas were derived.
by Jonathan Cheng 3C
Thu Dec 06, 2018 4:58 pm
Forum: Polyprotic Acids & Bases
Topic: Defintion
Replies: 11
Views: 291

Re: Defintion

A polyprotic acid is an acid that can donate more than one proton while a polyprotic base can accept more than one proton.
by Jonathan Cheng 3C
Sun Dec 02, 2018 9:59 pm
Forum: Naming
Topic: drawing ligands
Replies: 6
Views: 125

Re: drawing ligands

He drew the NH3 molecules as H3N because he wanted to show that the lone pair on the nitrogen bonds to the central atom
by Jonathan Cheng 3C
Sun Dec 02, 2018 9:38 pm
Forum: Bronsted Acids & Bases
Topic: Strong vs Weak Acid/Base Reactions
Replies: 4
Views: 81

Re: Strong vs Weak Acid/Base Reactions

The only way to tell whether the reaction is a strong acid/base or weak acid/base reaction is by looking at the acid or base that is reacting. There are more weak acids and bases than strong acids and bases. Thus, if you recognize that the acid or base that is not reacting is not a strong acid or ba...
by Jonathan Cheng 3C
Sun Dec 02, 2018 9:34 pm
Forum: Naming
Topic: Naming Question
Replies: 5
Views: 116

Re: Naming Question

Fe would have a charge of 2+ because OH2 has a charge of 0 so it does not affect the charge of the molecule. Cl has a charge of 1- and the overall charge of the molecule is 1+. Thus, Fe would have a charge of 2+ to allow the overall charge of the molecule to be 1+
by Jonathan Cheng 3C
Mon Nov 26, 2018 10:32 am
Forum: Hybridization
Topic: sigma vs. pi bonds
Replies: 4
Views: 82

Re: sigma vs. pi bonds

A single bond contains 1 sigma bond. A double contains 1 sigma bond and 1 pi bond. A triple bond contains 1 sigma bond and 2 pi bonds.
by Jonathan Cheng 3C
Mon Nov 26, 2018 10:31 am
Forum: Hybridization
Topic: pi bonds and rotation
Replies: 3
Views: 86

Re: pi bonds and rotation

Pi bonds do not allow free rotation. The pi bond results in a rigid structure and the two molecules would rotate together and they would not be able to rotate freely in their own plane. If a pi bond did freely rotate, the bonding regions would not remain intact.
by Jonathan Cheng 3C
Mon Nov 26, 2018 10:29 am
Forum: Hybridization
Topic: Just Kind of Confused
Replies: 13
Views: 238

Re: Just Kind of Confused

The order of the way the d orbital is written for hybridization does not matter. It can either be placed in front of the sp or behind it.
by Jonathan Cheng 3C
Mon Nov 19, 2018 9:35 pm
Forum: Hybridization
Topic: D-orbital
Replies: 5
Views: 125

Re: D-orbital

Either works although Lavelle says that he prefers to put the d in front of the sp
by Jonathan Cheng 3C
Mon Nov 19, 2018 9:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Double bonds
Replies: 8
Views: 186

Re: Double bonds

VSEPR only takes into account the number of regions of electron density, not the number of bonds a particular atom has bonded to it. Therefore, the double bonds would not be any different than a single or triple bond
by Jonathan Cheng 3C
Mon Nov 19, 2018 9:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining bond type
Replies: 4
Views: 81

Re: Determining bond type

Sigma bonds come first before pi bonds. Thus, a single bond consists of only one sigma bond. A double bond consists of a sigma bond and a pi bond. A triple bond consists of a sigma bond and two pi bonds.
by Jonathan Cheng 3C
Sun Nov 11, 2018 11:33 pm
Forum: Ionic & Covalent Bonds
Topic: Metallic Bond
Replies: 7
Views: 144

Re: Metallic Bond

A metallic bond is a bond shared between metal ions/cations
by Jonathan Cheng 3C
Sun Nov 11, 2018 11:30 pm
Forum: Bond Lengths & Energies
Topic: Bond lengths and resonance structure
Replies: 2
Views: 80

Re: Bond lengths and resonance structure

Yes, to determine the bond length in a molecule that exhibits resonance, finding the average bond length is used
by Jonathan Cheng 3C
Sun Nov 11, 2018 11:21 pm
Forum: Ionic & Covalent Bonds
Topic: Polar Covalent Bonds
Replies: 2
Views: 83

Re: Polar Covalent Bonds

Yes the rough guideline is if the difference in electronegativity is greater than 2, the bond is considered to be ionic
by Jonathan Cheng 3C
Sun Nov 04, 2018 8:23 pm
Forum: Lewis Structures
Topic: Identifying the central atom in ONF
Replies: 3
Views: 85

Re: Identifying the central atom in ONF

Nitrogen is the least electronegative atom, thus it is the central atom.
by Jonathan Cheng 3C
Sun Nov 04, 2018 8:12 pm
Forum: Lewis Structures
Topic: Expanded octets? + other octet exceptions
Replies: 3
Views: 61

Re: Expanded octets? + other octet exceptions

Hydrogen and Helium also only need 2 electrons to satisfy their valence shells
by Jonathan Cheng 3C
Sun Nov 04, 2018 8:11 pm
Forum: Resonance Structures
Topic: Most Stable Configuration
Replies: 11
Views: 266

Re: Most Stable Configuration

It is when all the formal charges are close to 0
by Jonathan Cheng 3C
Sun Oct 28, 2018 9:03 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron affinity
Replies: 1
Views: 64

Re: Electron affinity

Electron affinity is the energy released when an electron is added to a gas phase atom. The trend occurs because the electrons across a period or up a group, when added, are closer to the nucleus. Thus, it experiences a greater effective nuclear charge.
by Jonathan Cheng 3C
Sun Oct 28, 2018 9:00 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radius
Replies: 8
Views: 161

Re: Atomic Radius

We only need to know the general trend of atomic radii and the other properties. Information such as the specific atomic radii will be given to us on the test if it is needed to be used.
by Jonathan Cheng 3C
Sun Oct 28, 2018 8:57 pm
Forum: Trends in The Periodic Table
Topic: Exceptions to electron configuration
Replies: 3
Views: 164

Re: Exceptions to electron configuration

This occurs because the electron is taking from the s orbital and added to the d orbital to make it more stable. The s orbital now is half filled, which is relatively stable and the the d orbital is completely filled which is stable as well.
by Jonathan Cheng 3C
Sun Oct 21, 2018 4:11 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Conceptual Question
Replies: 2
Views: 66

Re: Conceptual Question

Quantum numbers describe energy and size (principal quantum #, n), shape (angular momentum quantum #, l), orbitals of a subshell (magnetic quantum #, ml) and spin (ms).
by Jonathan Cheng 3C
Sun Oct 21, 2018 4:06 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Lecture Question on Orbitals
Replies: 4
Views: 108

Re: Lecture Question on Orbitals

The quantum number m refers to the can take values from l to -l, thus when m=-1 where l is equal to one, the electron is contained in the first subshell. Thus, it would be in the 2px subshell.
by Jonathan Cheng 3C
Sun Oct 21, 2018 4:01 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Shielding
Replies: 5
Views: 105

Re: Shielding

Shielding is essentially when electrons in more outer shells experience less of an effective nuclear charge due to the electrons in the inner shells.
by Jonathan Cheng 3C
Sun Oct 14, 2018 5:10 pm
Forum: DeBroglie Equation
Topic: De Broglie Equation Example
Replies: 4
Views: 97

Re: De Broglie Equation Example

The wavelength found, 1.64 * 10^-38 m, is so small that the waves would not be able to be detected. Thus, the car does not have any measurable wavelike properties.
by Jonathan Cheng 3C
Sun Oct 14, 2018 5:04 pm
Forum: Properties of Light
Topic: Example from Friday's Lecture (10/12/18)
Replies: 3
Views: 51

Re: Example from Friday's Lecture (10/12/18)

9.11 * 10^-31 kg is the weight of an electron. This value is given
by Jonathan Cheng 3C
Sun Oct 14, 2018 4:49 pm
Forum: Properties of Electrons
Topic: Photoelectric Experiment
Replies: 9
Views: 141

Re: Photoelectric Experiment

By increasing the intensity of light, the amount of photons are increased, not the amount of energy each individual photon contains. Because each photon interacts with one electron, the amount of photons does not cause electrons to be emitted.
by Jonathan Cheng 3C
Thu Oct 04, 2018 5:53 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Finding remaining mass of hydrate
Replies: 1
Views: 69

Re: Finding remaining mass of hydrate

(360 g CuSO4*5H2O) * (1 mol CuSO4*5H2O / 249.68 g CuSO4*5H2O) * (5 mol H2O / 1 mol CuSO4*5H2O) * (18 g H2O / 1 mol H2O) = 129.76 g H2O This conversion gives the amount of water present in 360g of copper sulfate pentahydrate. When 90% of water is removed, then 116.79 g of H2O is removed. 360g - 116.7...
by Jonathan Cheng 3C
Thu Oct 04, 2018 5:29 pm
Forum: Significant Figures
Topic: Molar Mass
Replies: 5
Views: 133

Re: Molar Mass

Use the molar mass provided regardless of the significant figures. Only round the final answer to the correct amount of significant figures needed.
by Jonathan Cheng 3C
Thu Oct 04, 2018 5:21 pm
Forum: SI Units, Unit Conversions
Topic: Formula Units
Replies: 1
Views: 92

Re: Formula Units

Formula units refers to the number of atoms present. In this case, there are 1.26 * 10^22 formula units present in 5.15g of magnesium sulfate heptahydrate.
((5.15 g MgSO4 * 7H2O) / 246.5 g mol^-1) *(6.022*10^23 atoms mol^-1) = 1.26 *10^22 atoms.

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