Search found 30 matches

by 305117729
Fri Dec 07, 2018 10:18 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strength of acid
Replies: 4
Views: 72

Re: Strength of acid

Elements that down the group are generally larger in ionic radii, so the attraction from the nucleus will be weak, and the acids formed by these elements will be easily dissociated in water.
by 305117729
Fri Dec 07, 2018 10:16 pm
Forum: Identifying Acidic & Basic Salts
Topic: Identifying Acidic & Basic Salts
Replies: 1
Views: 56

Identifying Acidic & Basic Salts

How could I know a salt is acidic or basic when it is formed by a weak acid and a weak base?
by 305117729
Fri Dec 07, 2018 10:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate ligands
Replies: 2
Views: 54

Re: Polydentate ligands

that depends on the property and shape of the ligand. Basically, a polydentate ligand will have multiple number of lone pair electrons and the angle between each is around 90˚.
by 305117729
Fri Dec 07, 2018 10:10 pm
Forum: Naming
Topic: naming
Replies: 5
Views: 102

Re: naming

For cyano- we need to know it's -1, and for the charge on metal ion we could basically calculate it.
by 305117729
Fri Dec 07, 2018 10:08 pm
Forum: Hybridization
Topic: pi vs sigma
Replies: 12
Views: 177

Re: pi vs sigma

sigma bonds are formed by two orbitals overlapping at one point, but pi bonds are formed by overlapping at two points, each one is weaker than the single one point, so easier to break pi bonds.
by 305117729
Fri Dec 07, 2018 10:03 pm
Forum: Ionic & Covalent Bonds
Topic: bond length
Replies: 3
Views: 90

Re: bond length

P has more shells of electron and less attraction from the nucleus.
by 305117729
Fri Dec 07, 2018 10:02 pm
Forum: Lewis Structures
Topic: Elements that break the octet rule
Replies: 6
Views: 99

Re: Elements that break the octet rule

Generally, elements with d orbital, e.g. elements in 3rd period, will have expanded octet
by 305117729
Fri Dec 07, 2018 9:56 pm
Forum: Sigma & Pi Bonds
Topic: Which bond would break first.
Replies: 13
Views: 240

Re: Which bond would break first.

pi bonds will break first, as they are weaker than sigma bonds.
by 305117729
Fri Dec 07, 2018 9:54 pm
Forum: Electronegativity
Topic: Ionic Character
Replies: 5
Views: 106

Re: Ionic Character

Generally, the greater the difference between two atoms forming the ion, the greater ionic character this ion will show
by 305117729
Fri Dec 07, 2018 9:47 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pKa versus pKb versus Ka versus Kb [ENDORSED]
Replies: 2
Views: 62

Re: pKa versus pKb versus Ka versus Kb [ENDORSED]

Ka is the indicator of strength of an acid, the greater it is the stronger the acid will be.
pKa = -log[Ka] so the greater pKa is the weaker the acid will be.
Kb and pKb work the same way but for bases.
by 305117729
Fri Dec 07, 2018 9:44 pm
Forum: Lewis Acids & Bases
Topic: Weak Acids/Bases?
Replies: 5
Views: 87

Re: Weak Acids/Bases?

Weak acids include all organic acids.
by 305117729
Fri Dec 07, 2018 9:35 pm
Forum: Air Pollution & Acid Rain
Topic: ACID RAIN
Replies: 5
Views: 241

Re: ACID RAIN

All rain is acidic because CO2 in air will be dissolved and form carbonic acid; however, acid rain are formed by SO2 dissolved in water and forming sulfuric acid which is a strong acid and more harmful.
by 305117729
Fri Dec 07, 2018 9:31 pm
Forum: Bronsted Acids & Bases
Topic: Alkali vs Alkaline
Replies: 2
Views: 44

Re: Alkali vs Alkaline

Alkali metals are 1st group metals and Alkaline metals are 2nd group. Generally Alkali metals form stronger bases comparing to the Alkaline metals in the same period.
by 305117729
Fri Dec 07, 2018 9:28 pm
Forum: Lewis Acids & Bases
Topic: HCl vs. HI
Replies: 7
Views: 81

Re: HCl vs. HI

When evaluating acidity, it's more likely to consider the extent of dissociation of acids in water, which means if an acid gives more H+ ions it will be stronger, so we will see HI as the stronger acid as the HI bond is weaker and it will give more H+ ions.
by 305117729
Fri Dec 07, 2018 9:23 pm
Forum: Bronsted Acids & Bases
Topic: acidity
Replies: 4
Views: 73

Re: acidity

longer bonds stand for less attraction as the valence electrons are further from the nucleus, and the dissociation of acid gives H+ and decrease the pH, so acids with longer bonds will give more H+ ion and thus are stronger acids.
by 305117729
Fri Dec 07, 2018 9:18 pm
Forum: Conjugate Acids & Bases
Topic: Water as an Acid/Base
Replies: 8
Views: 72

Re: Water as an Acid/Base

water's identity depends on the reaction it's involved in. When acids are dissociated in water, water reacts as a base, while water reacts as an acid when bases are dissociated in water.
by 305117729
Fri Dec 07, 2018 9:15 pm
Forum: Lewis Acids & Bases
Topic: Strong Acids
Replies: 6
Views: 87

Re: Strong Acids

HI has longer bond than HF, so it will be more easily dissociated in water, and this results in stronger acidity.
by 305117729
Fri Dec 07, 2018 9:14 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid dissociation
Replies: 5
Views: 60

Re: Acid dissociation

most acids and bases will not dissociate 100%, but in our course we currently assume they are 100% dissociated.
by 305117729
Sun Dec 02, 2018 9:51 pm
Forum: Hybridization
Topic: hybridization
Replies: 13
Views: 185

Re: hybridization

the number of hybridized orbitals is the same as the number of electron densities. e.g. a tetrahedral molecule has four electron densities, so it's sp3 hybridized.
by 305117729
Sun Dec 02, 2018 9:49 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Sigma and Pi Bonds
Replies: 6
Views: 122

Re: Sigma and Pi Bonds

yes. One double bond consists of one sigma bond and one pi bond, and one triple bond consist of one sigma bond and two pi bonds.
by 305117729
Sun Dec 02, 2018 9:46 pm
Forum: Hybridization
Topic: Pi bonds in triple bond
Replies: 17
Views: 352

Re: Pi bonds in triple bond

two pi bonds and one sigma bond
by 305117729
Sun Nov 25, 2018 11:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: pi-bonds
Replies: 7
Views: 70

Re: pi-bonds

pi bond is formed by overlapping between p orbitals, or say parallel interactions between p orbitals. So it will only be formed when two atoms with their p orbitals overlapping, and it means that only when a double or triple bond formed, pi bonds will be formed, since the s orbitals form the single ...
by 305117729
Sun Nov 25, 2018 11:37 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR model
Replies: 4
Views: 54

Re: VSEPR model

A is the central atom, X is the atom bond to A, and E is lone pair electrons on A. Knowing this, we are able to know the number of electron density around the central atom A. e.g. AX4 stands for 4 atoms bond to central atom, and there's no lone pairs, so there are 4 electron density around A, and th...
by 305117729
Sun Nov 25, 2018 11:33 pm
Forum: Sigma & Pi Bonds
Topic: Number of sigma and pi bonds
Replies: 5
Views: 134

Re: Number of sigma and pi bonds

There is an easy way to count sigma and pi bonds. One single bond is one sigma bond, and one double bond consists of one sigma bond and one pi bond, a triple bond one sigma bond and two pi bonds. So if you simply want to know the number of each bond, you could just count the number of single, double...
by 305117729
Sun Nov 18, 2018 4:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Octahedral
Replies: 2
Views: 59

Re: Octahedral

Octahedral shape refers to the geometry that has eight faces, oct meaning eight. An octahedral molecule has six electron density, one at the top, one at the bottom, and four in the middle, forming eight faces in total. Just try to visualize an octahedral molecule, and see how the geometry is shaped.
by 305117729
Sun Nov 18, 2018 4:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Square Planar vs Tetrahedral
Replies: 8
Views: 126

Re: Square Planar vs Tetrahedral

square planar has 6 electron domains and 4 of them are forming bonds, 2 lone pairs. while tetrahedral shape has 4 electron domains and all of them form bond, no lone pair
by 305117729
Sun Nov 18, 2018 3:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angle and bond strength
Replies: 4
Views: 50

bond angle and bond strength

will the bond strength affect the bond angle in a molecule? do molecules like CF4 and CF2Cl2 have the same bond angle? if not how are the bond angles changed?
by 305117729
Sun Nov 11, 2018 2:10 pm
Forum: Resonance Structures
Topic: Drawing resonance
Replies: 17
Views: 308

Drawing resonance

When we are drawing lewis structure of one molecule, should we always draw all resonance of this molecule?
by 305117729
Sun Nov 11, 2018 2:08 pm
Forum: Dipole Moments
Topic: Dipole moment
Replies: 4
Views: 58

Dipole moment

Is there a way to determine if one molecule has net dipole moment?
by 305117729
Sun Nov 11, 2018 2:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSPER and bond strength
Replies: 2
Views: 35

VSPER and bond strength

Are the repulsion between bond pairs influenced by the strength of those bond? do stronger bonds have greater repulsion?

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