Search found 31 matches

by Joaquin Andrade
Fri Dec 07, 2018 11:24 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Chem 6th Edition 12.25
Replies: 2
Views: 46

Re: Chem 6th Edition 12.25

Divide Kw by the concentration of OH- to find the concentration of H3O+.
by Joaquin Andrade
Fri Dec 07, 2018 11:21 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Difference Between Polarizability and Polarizing Power
Replies: 3
Views: 66

Re: Difference Between Polarizability and Polarizing Power

Polarizing power corresponds to cations, the most polarizing power being found in the smallest cations with he greatest positive charge. On the other hand, polarizability corresponds to anions. The anions with the greater polarizability are the biggest.
by Joaquin Andrade
Fri Dec 07, 2018 11:11 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 11
Views: 177

Re: Polydentate

If a ligand can bond to the central metal atom with two atoms, it is bidentate. For three atoms, it is tridentate. For any more, the term polydentate is typically used.
by Joaquin Andrade
Fri Dec 07, 2018 11:09 pm
Forum: Electronegativity
Topic: Ionic Character
Replies: 5
Views: 80

Re: Ionic Character

Oxygen is actually more electronegative since Cl is a period down and thus is affected by shielding. This can be verified in the actual electronegativity values for O and Cl.
by Joaquin Andrade
Fri Dec 07, 2018 11:04 pm
Forum: Amphoteric Compounds
Topic: Oxalate bidentate
Replies: 4
Views: 46

Re: Oxalate bidentate

It's shape only for the singly-bonded oxygen atoms to bond to a central atom or ion.
by Joaquin Andrade
Fri Dec 07, 2018 11:01 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Function of polydentate ligand
Replies: 2
Views: 41

Re: Function of polydentate ligand

Polydentate ligands have more than one atom which is able to form a bond to a central atom. For instance, EDTA is a polydentate ligand which has six atoms with electron pairs that can be used to bond to a central metal atom.
by Joaquin Andrade
Fri Dec 07, 2018 10:54 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: Review questions
Replies: 3
Views: 57

Re: Review questions

Both species have 2 hydrogens, so we want to focus on the S and Se. Se will have higher polarizability because it is the bigger atom. Thus the instantaneous dipoles (London Dispersion Forces) formed between several H2Se molecules will be greater in strength than in H2S. We can conclude that H2Se has...
by Joaquin Andrade
Fri Dec 07, 2018 10:49 pm
Forum: Dipole Moments
Topic: Differences in electronegativity
Replies: 2
Views: 62

Re: Differences in electronegativity

Note also that difference in electronegativity could make an entire molecule polar. For instance, NH3 (Ammonia) is polar while CH4 is not due to the contrast in electronegativity differences in the respective molecules.
by Joaquin Andrade
Fri Dec 07, 2018 10:46 pm
Forum: Bronsted Acids & Bases
Topic: 6A.9
Replies: 2
Views: 46

Re: 6A.9

Acetat (CH3COOH) is a weak acid and thus will give off the H+ proton to NH3, thereby the products are NH4+ (ammonium) and CH3COO-.
by Joaquin Andrade
Fri Dec 07, 2018 10:42 pm
Forum: Bronsted Acids & Bases
Topic: Cl- and F-
Replies: 4
Views: 53

Re: Cl- and F-

Since HCL is a strong acid, it will stay dissociated in water. This is also true for HBr and HI.
by Joaquin Andrade
Fri Dec 07, 2018 10:39 pm
Forum: Hybridization
Topic: Sigma and pi bonds
Replies: 4
Views: 64

Re: Sigma and pi bonds

We should know the hybridization, in terms of how sp3 corresponds to four regions of electron density.
by Joaquin Andrade
Fri Dec 07, 2018 10:35 pm
Forum: Dipole Moments
Topic: Dipole dipole moments
Replies: 3
Views: 66

Re: Dipole dipole moments

There is no net dipole moment, as CH bonds are considered non polar because of the low electronegative difference.
by Joaquin Andrade
Fri Dec 07, 2018 10:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Correct Bond Angles
Replies: 6
Views: 86

Re: Correct Bond Angles

A general rule of thumb to remember is that the more lone pairs there are, the smaller the bond angle.
by Joaquin Andrade
Fri Dec 07, 2018 10:21 pm
Forum: Sigma & Pi Bonds
Topic: Rotation
Replies: 5
Views: 81

Re: Rotation

Sigma bonds bond end to end, allowing for more rotation (you can try this with your fingers). On the other hand, pi bonds bond side to side, allowing no rotation to occur between molecules, and thus fixing them in place.
by Joaquin Andrade
Fri Dec 07, 2018 10:11 pm
Forum: Lewis Acids & Bases
Topic: Ligands
Replies: 7
Views: 92

Re: Ligands

A neutral coordination does not contribute to the charge of a coordination compound. Examples include: NH3 (ammine), H2O (aqua), NO (nitrosyl), CO (carbonyl),ethylenediamine, and and diethylenetriamine.
by Joaquin Andrade
Fri Dec 07, 2018 10:04 pm
Forum: Bronsted Acids & Bases
Topic: Problem J.7 - 7th Ed.
Replies: 4
Views: 70

Re: Problem J.7 - 7th Ed.

Since the oxidation number of Zn is +1, the formula is Zn(NO2)
by Joaquin Andrade
Fri Dec 07, 2018 10:01 pm
Forum: Ionic & Covalent Bonds
Topic: bond length
Replies: 3
Views: 72

Re: bond length

Because of the shielding effect - since P is a period down from N it has more electrons and thus the pull of the nucleus is weaker, thereby increasing the covalent radius and thus the bond length.
by Joaquin Andrade
Fri Dec 07, 2018 9:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: ClO2- lewis structure
Replies: 4
Views: 76

Re: ClO2- lewis structure

A single bond to an oxygen will result in a formal charge of 1- for the oxygen. From the fact the molecule has a charge, we can conclude that one of the Cl bonds to oxygen will be a single bond. The other must be a double bond.
by Joaquin Andrade
Fri Dec 07, 2018 9:56 pm
Forum: Bond Lengths & Energies
Topic: Shape of molecule
Replies: 4
Views: 79

Re: Shape of molecule

Rod shaped molecules have a higher surface area.Because there is higher surface area, there is a higher incidence of instantaneous dipoles, which occur randomly but more frequently in this case.
by Joaquin Andrade
Fri Dec 07, 2018 9:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: H-bonds
Replies: 4
Views: 62

Re: H-bonds

Hydrogen bonds are found in molecules which are polar, and must include F, O, or N bonded to a H. Note that Hydrogen bonds are intermolecular forces, so the entire molecule is considered polar.
by Joaquin Andrade
Fri Dec 07, 2018 9:50 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 3
Views: 65

Re: Polarizability

The bigger atom will be more polarizable, so going a group, the polarizability of atoms will increase. This includes group 17, in which case I- would have higher polarizability.
by Joaquin Andrade
Fri Dec 07, 2018 9:44 pm
Forum: Air Pollution & Acid Rain
Topic: ACID RAIN
Replies: 5
Views: 227

Re: ACID RAIN

Acid rain often forms from the reaction between CO2 and H2O. The resulting product is H2CO3, which is carbonic acid.
by Joaquin Andrade
Wed Dec 05, 2018 1:42 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 2
Views: 49

Re: Electronegativity

Because Cl is a period beneath O, it is affected by shielding, which reduces the pull of the nucleus on valence electrons. Thus, O will be more electronegative even though Cl is a group to the right.
by Joaquin Andrade
Wed Dec 05, 2018 11:39 am
Forum: Sigma & Pi Bonds
Topic: Identifying sigma & pi bonds
Replies: 4
Views: 81

Re: Identifying sigma & pi bonds

When drawing the bonds, make sure to emphasize the overlap between the orbitals. The pi bond will be side to side, which is why these bonds lock two molecules into place as opposed to sigma bonds which are side to side and allow molecules to rotate.
by Joaquin Andrade
Wed Dec 05, 2018 11:32 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: Determining possible intermolecular forces
Replies: 3
Views: 57

Re: Determining possible intermolecular forces

Dipole moments can also be found in polar molecules, depending on the electronegativity difference and the shape of the molecule. For instance, a tetrahedral allows for a dipole moment to occur whereas in an octahedral the non-central atoms pull away from each and cancel each other out.
by Joaquin Andrade
Wed Dec 05, 2018 11:13 am
Forum: Lewis Acids & Bases
Topic: J.19
Replies: 1
Views: 36

Re: J.19

We are instructed to write the reaction, so first we write the reactants, which in this case include the acidic oxide and water. For CO2 and H2O, the resulting acid will be H2CO3. The coefficients will all be 1. For SO3, the resulting acid will be H2SO4. In this case the coefficients will also all b...
by Joaquin Andrade
Sun Nov 11, 2018 1:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Q. 4.1B
Replies: 1
Views: 120

Re: Q. 4.1B

Only the lone pairs around the central atom will matter. While a linear molecule may have lone pairs, not all molecules with 2 bonding pairs and a certain number lone pairs will be linear. For instance, in H2O the central atom oxygen will have 2 lone pairs and thus the molecular geometry will be ben...
by Joaquin Andrade
Sun Nov 11, 2018 12:47 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.12 Homework Problem
Replies: 1
Views: 25

Re: 4.12 Homework Problem

To draw the lewis structure, we first add up the total valence electrons. Phosphorus has 5 valence electrons, and there are 7 for each fluoride, so the total is 33. However, there is a negative 1 charge so we add one more for a total of 34. Phosphorus has the lower ionization energy so it is the cen...
by Joaquin Andrade
Sat Nov 10, 2018 9:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: how to know which shape it is
Replies: 6
Views: 98

Re: how to know which shape it is

The difference is in the number of valence electron lone pairs. Trigonal planar has zero lone pairs, trigonal pyramidal has one lone pair, and t-shaped has two lone pairs.
by Joaquin Andrade
Sat Nov 10, 2018 8:25 pm
Forum: Bond Lengths & Energies
Topic: Potential Energy Equation
Replies: 1
Views: 48

Re: Potential Energy Equation

This potential energy equation applies to London dispersion force interactions, in which the alpha values denote the polarizability of the respective molecules. According to the equation, the potential energy of two molecules in a London dispersion interaction increases with greater polarizability o...
by Joaquin Andrade
Sat Nov 10, 2018 6:33 pm
Forum: Lewis Structures
Topic: polyatomic ions
Replies: 2
Views: 54

Re: polyatomic ions

To draw the lewis structures of polyatomic ions we first add up the total valence electrons. For instance, take sulfate SO4 -2. Both sulfur and oygen have 6 valence electrons - there are 4 oxygens so the total number of electrons is 30. But since the charge is -2 we add 2 electrons for a total of 32...

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