Search found 30 matches
- Fri Dec 07, 2018 10:18 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Strength of acid
- Replies: 4
- Views: 565
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.
- Fri Dec 07, 2018 10:16 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Identifying Acidic & Basic Salts
- Replies: 1
- Views: 417
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?
- Fri Dec 07, 2018 10:13 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate ligands
- Replies: 2
- Views: 359
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˚.
Re: naming
For cyano- we need to know it's -1, and for the charge on metal ion we could basically calculate it.
- Fri Dec 07, 2018 10:08 pm
- Forum: Hybridization
- Topic: pi vs sigma
- Replies: 12
- Views: 1227
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.
- Fri Dec 07, 2018 10:03 pm
- Forum: Ionic & Covalent Bonds
- Topic: bond length
- Replies: 3
- Views: 590
Re: bond length
P has more shells of electron and less attraction from the nucleus.
- Fri Dec 07, 2018 10:02 pm
- Forum: Lewis Structures
- Topic: Elements that break the octet rule
- Replies: 6
- Views: 853
Re: Elements that break the octet rule
Generally, elements with d orbital, e.g. elements in 3rd period, will have expanded octet
- Fri Dec 07, 2018 9:56 pm
- Forum: Sigma & Pi Bonds
- Topic: Which bond would break first.
- Replies: 15
- Views: 2731
Re: Which bond would break first.
pi bonds will break first, as they are weaker than sigma bonds.
- Fri Dec 07, 2018 9:54 pm
- Forum: Electronegativity
- Topic: Ionic Character
- Replies: 7
- Views: 1562
Re: Ionic Character
Generally, the greater the difference between two atoms forming the ion, the greater ionic character this ion will show
- 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: 342
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.
pKa = -log[Ka] so the greater pKa is the weaker the acid will be.
Kb and pKb work the same way but for bases.
- Fri Dec 07, 2018 9:44 pm
- Forum: Lewis Acids & Bases
- Topic: Weak Acids/Bases?
- Replies: 5
- Views: 728
Re: Weak Acids/Bases?
Weak acids include all organic acids.
- Fri Dec 07, 2018 9:35 pm
- Forum: Air Pollution & Acid Rain
- Topic: ACID RAIN
- Replies: 5
- Views: 840
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.
- Fri Dec 07, 2018 9:31 pm
- Forum: Bronsted Acids & Bases
- Topic: Alkali vs Alkaline
- Replies: 2
- Views: 492
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.
- Fri Dec 07, 2018 9:28 pm
- Forum: Lewis Acids & Bases
- Topic: HCl vs. HI
- Replies: 7
- Views: 789
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.
- Fri Dec 07, 2018 9:23 pm
- Forum: Bronsted Acids & Bases
- Topic: acidity
- Replies: 4
- Views: 593
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.
- Fri Dec 07, 2018 9:18 pm
- Forum: Conjugate Acids & Bases
- Topic: Water as an Acid/Base
- Replies: 20
- Views: 1571
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.
- Fri Dec 07, 2018 9:15 pm
- Forum: Lewis Acids & Bases
- Topic: Strong Acids
- Replies: 6
- Views: 631
Re: Strong Acids
HI has longer bond than HF, so it will be more easily dissociated in water, and this results in stronger acidity.
- Fri Dec 07, 2018 9:14 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acid dissociation
- Replies: 5
- Views: 530
Re: Acid dissociation
most acids and bases will not dissociate 100%, but in our course we currently assume they are 100% dissociated.
- Sun Dec 02, 2018 9:51 pm
- Forum: Hybridization
- Topic: hybridization
- Replies: 13
- Views: 1816
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.
- Sun Dec 02, 2018 9:49 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Sigma and Pi Bonds
- Replies: 6
- Views: 961
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.
- Sun Dec 02, 2018 9:46 pm
- Forum: Hybridization
- Topic: Pi bonds in triple bond
- Replies: 17
- Views: 1894
Re: Pi bonds in triple bond
two pi bonds and one sigma bond
- Sun Nov 25, 2018 11:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: pi-bonds
- Replies: 7
- Views: 678
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 ...
- Sun Nov 25, 2018 11:37 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR model
- Replies: 4
- Views: 427
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...
- Sun Nov 25, 2018 11:33 pm
- Forum: Sigma & Pi Bonds
- Topic: Number of sigma and pi bonds
- Replies: 5
- Views: 1073
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...
- Sun Nov 18, 2018 4:05 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Octahedral
- Replies: 2
- Views: 376
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.
- Sun Nov 18, 2018 4:00 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Square Planar vs Tetrahedral
- Replies: 8
- Views: 2443
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
- Sun Nov 18, 2018 3:55 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: bond angle and bond strength
- Replies: 4
- Views: 819
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?
- Sun Nov 11, 2018 2:10 pm
- Forum: Resonance Structures
- Topic: Drawing resonance
- Replies: 17
- Views: 1892
Drawing resonance
When we are drawing lewis structure of one molecule, should we always draw all resonance of this molecule?
- Sun Nov 11, 2018 2:08 pm
- Forum: Dipole Moments
- Topic: Dipole moment
- Replies: 4
- Views: 448
Dipole moment
Is there a way to determine if one molecule has net dipole moment?
- Sun Nov 11, 2018 2:06 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSPER and bond strength
- Replies: 2
- Views: 162
VSPER and bond strength
Are the repulsion between bond pairs influenced by the strength of those bond? do stronger bonds have greater repulsion?