Search found 31 matches
- Sat Jun 09, 2018 7:07 pm
- Forum: Amphoteric Compounds
- Topic: As2O3
- Replies: 4
- Views: 1001
Re: As2O3
In order for it to be amphoteric, it means that the oxide can react either with acid or base. In the case of As2O3 we have the reaction with acid: As2O3 + 6HCl --> 2AsCl3 + 3H2O, and reaction with base NaOH + As2O3 + 3H2O --> 2Na[As(OH)4]. It also applies to Bi2O3.
- Sat Jun 09, 2018 7:03 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: 17.33
- Replies: 1
- Views: 297
Re: 17.33
Carbonate is monodentate because it only has 120 degrees between its Oxygens, so two oxygens cannot bind to the same metal. However, in some cases carbonate bonds to two different metals, making it a bidentate.
- Sat Jun 09, 2018 6:56 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligand shape
- Replies: 2
- Views: 371
Re: Ligand shape
Chelation is a process in which polydentate ligand bonds to a metal ion, forming a ring. The complex produced by this process is called a chelate, and the polydentate ligand is referred to as a chelating agent. It functions as two associating units and fastens to the central atom to produce heterocy...
- Sat Jun 09, 2018 6:47 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation Number
- Replies: 5
- Views: 917
Re: Oxidation Number
The oxidation number of a free element is always 0. The oxidation number of a monatomic ion equals the charge of the ion. The oxidation number of a Group 1 element in a compound is +1. The oxidation number of a Group 2 element in a compound is +2. The sum of the oxidation numbers of all of the atoms...
- Sat Jun 09, 2018 6:41 pm
- Forum: Conjugate Acids & Bases
- Topic: Difference between Lewis and conjugate acids and bases
- Replies: 4
- Views: 3573
Re: Difference between Lewis and conjugate acids and bases
A conjugate acid is a base with a hydrogen ion added to it. On the other hand, a conjugate base is what is left over after an acid has donated a proton during a chemical reaction.
- Sat Jun 09, 2018 6:38 pm
- Forum: Octet Exceptions
- Topic: expanded octet
- Replies: 12
- Views: 2734
Re: expanded octet
The extent to what it can expand to, or if it can even have an extended octet depends on the element.
- Sat Jun 09, 2018 6:34 pm
- Forum: Bond Lengths & Energies
- Topic: Bond length
- Replies: 5
- Views: 823
Re: Bond length
Draw the Lewis structure, look up the chart below for the radii for the corresponding bond, and find the sum of the two radii. Because the bond length is proportional to the atomic radius, the bond length trends in the periodic table follow the same trends as atomic radii: bond length decreases acro...
- Tue May 29, 2018 6:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Homework 4.7
- Replies: 3
- Views: 461
Re: Homework 4.7
The OSCl angles are all the same because the long pair repels them equally. , since the shape is a trigonal pyramidal, the angles will be slightly less than 109.5. OSCl is a radical with an unpaired lone pair. Being a radical, it wants a paired electron and is treated as an anion when writing the VS...
- Tue May 29, 2018 6:09 pm
- Forum: Air Pollution & Acid Rain
- Topic: Acid deposition
- Replies: 2
- Views: 966
Re: Acid deposition
Acid precipitation is often caused by the release of sulfur dioxide and nitrogen oxides into the atmosphere where they combine with atmospheric gases and water to create more acidic compounds. These chemicals are released during the combustion of fossil fuels from places like power plants, factories...
- Tue May 29, 2018 6:01 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar VS Nonpolar shapes
- Replies: 4
- Views: 577
Re: Polar VS Nonpolar shapes
If a molecule is completely symmetric, then the dipole moment vectors on each molecule will cancel each other out, making the molecule nonpolar. A molecule can only be polar if the structure of that molecule is not symmetric. Dipole moments need to have equal strength.
- Tue May 29, 2018 5:54 pm
- Forum: Bond Lengths & Energies
- Topic: Energies
- Replies: 4
- Views: 639
Re: Energies
Find the formal charge of each molecule and also its electronegativity.
- Tue May 29, 2018 5:53 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: I3- Molecular Shape
- Replies: 2
- Views: 1679
Re: I3- Molecular Shape
I3- has three lone pairs in the equatorial position, however, since they are equally spaced they repel the axial I equally, resulting in a linear shape. I3- has 2 bonds and 3 lone pairs for 5 regions of electron density. Placing that into a trigonal bipyramidal structure, the lone pairs go equatoria...
- Tue May 29, 2018 5:42 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone pairs on non-central atoms
- Replies: 4
- Views: 806
Re: Lone pairs on non-central atoms
As soon as a lone pair exists on a central atom, there is a tendency to have the lone pair occupy an orbital with an s-contribution as high as possible and to have bonding orbitals with a maximized p-contribution. p-orbitals, having a direction, can form stronger σ bonds due to better overlap. This ...
- Tue May 29, 2018 5:35 pm
- Forum: Resonance Structures
- Topic: Resonance [ENDORSED]
- Replies: 5
- Views: 946
Re: Resonance [ENDORSED]
It means that any of the other resonance structures need to have a formal charge similar to the original resonance structure. I believe this is what you're asking.
- Tue May 29, 2018 5:28 pm
- Forum: Empirical & Molecular Formulas
- Topic: Finding Empirical and Molecular Formula [ENDORSED]
- Replies: 6
- Views: 988
Re: Finding Empirical and Molecular Formula [ENDORSED]
You should look at the number of elements, not the bonds. Bonds are not for finding the empirical or molecular formula.
- Tue May 29, 2018 5:20 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizing Power vs. Polarizability
- Replies: 1
- Views: 1233
Re: Polarizing Power vs. Polarizability
A cation's polarizing power relates to its ability to attract the valence electron shell from a nearby anion in ionic compounds and the tendency of the anion to become polarized by the cation is known as its polarizability. They are both related to the covalent character of ionic bonds. The electron...
- Tue May 29, 2018 5:14 pm
- Forum: Lewis Acids & Bases
- Topic: Boron and the octet rule [ENDORSED]
- Replies: 7
- Views: 1589
Re: Boron and the octet rule [ENDORSED]
The only atoms that are the exceptions of the octet rule are lithium, beryllium, boron, and Aluminum.
- Tue May 29, 2018 5:09 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs
- Replies: 2
- Views: 354
Re: Lone Pairs
Bond angle is affected by the presence of a lone pair of electrons at the central atom. A lone pair of electrons at the central atom will always try to repel the bonded pair of electrons(Also called the lone pair repulsion). Therefore, the bonds are displaced slightly inside resulting in a decrease ...
- Tue May 29, 2018 5:05 pm
- Forum: Ionic & Covalent Bonds
- Topic: Double/Triple Bonds
- Replies: 8
- Views: 1043
Re: Double/Triple Bonds
There is no certainty of any atom needing a certain number of bonds. Usually, triple or double bonds are created in order to fulfill the octet rule. However, just because you can make those bonds, it is necessary to create a structure that will be the most stable and have a formal charge of zero.
- Sat May 05, 2018 7:54 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Significance of - sign
- Replies: 2
- Views: 413
Re: Significance of - sign
The wavenumber is related in initial and final stages. On the energy scale, a free electron is assigned to the equation with the value of zero joules. This corresponds to the infinite levels of the atom. in Other words, it means that all energy levels in the atom are below this value and are therefo...
- Sat May 05, 2018 7:37 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Midterm Review 6C
- Replies: 1
- Views: 296
Re: Midterm Review 6C
Affinity is the change in energy of the atom when an electron is added. Noble Gases are at the perfect number of 8 electrons. They don't need anymore electrons, so there's zero change in the energy of the atom. All of the Noble Gases have electron affinity less than or equal to 0.
- Sat May 05, 2018 7:33 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Confusion about why there is no 1p, 1d, or 1f orbital? [ENDORSED]
- Replies: 4
- Views: 9071
Re: Confusion about why there is no 1p, 1d, or 1f orbital? [ENDORSED]
In the first shell, there is only the 1s orbital, the shell can have a maximum of only 2 electrons. Therefore, the 1p, 1d, or 1f does not exist. The quantum number "n" must be larger than angular momentum quantum number. For example, n = 1, only l = 0 gives a valid wave function, for n = 2...
- Sun Apr 22, 2018 2:15 pm
- Forum: Einstein Equation
- Topic: constants [ENDORSED]
- Replies: 2
- Views: 409
Re: constants [ENDORSED]
All formulas are provided, however, you will need to know what each variable means and know when to use a certain formula on a problem.
- Sun Apr 22, 2018 2:12 pm
- Forum: Properties of Light
- Topic: Electromagnetic Spectrum [ENDORSED]
- Replies: 7
- Views: 792
Re: Electromagnetic Spectrum [ENDORSED]
It is important to be familiarized with the spectrum and their ranges, it is important to know which has the highest and lowest intensity and be able to explain how they work with wavelength and frequency.
- Sun Apr 22, 2018 2:09 pm
- Forum: Einstein Equation
- Topic: E=hv vs E=hf [ENDORSED]
- Replies: 4
- Views: 4347
Re: E=hv vs E=hf [ENDORSED]
Both equations are the same, they both stand for frequency. That is the frequency of the photon that is coming in or being released.
- Sun Apr 15, 2018 6:47 pm
- Forum: Limiting Reactant Calculations
- Topic: Reactants and reagents
- Replies: 2
- Views: 439
Re: Reactants and reagents
The only difference is that the reactant is always a participant in a chemical reaction while the reagent has a broader meaning. Reactants can be Elements or compounds, but not mixture. Reagents are generally mixture containing one of the reactants and some other chemicals that help to stabilize the...
- Sun Apr 15, 2018 6:38 pm
- Forum: *Black Body Radiation
- Topic: What is Significant about Black Body Radiation? [ENDORSED]
- Replies: 4
- Views: 1126
Re: What is Significant about Black Body Radiation? [ENDORSED]
Black body radiation basically absorbs all radiation falling on it, at all wavelengths. As the temperature decreases, the peak of the black-body radiation curve moves to lower intensities and longer wavelengths.It is important because in radiation we use black body radiation at a certain wavelength ...
- Sun Apr 15, 2018 6:17 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical and Molecular the same [ENDORSED]
- Replies: 3
- Views: 605
Empirical and Molecular the same [ENDORSED]
How can the empirical formula of a visual representation of the structure of a molecule be identified? For example, If it was given the molecular formula to be CH7O, is the empirical formula the same?
- Sun Apr 15, 2018 6:07 pm
- Forum: SI Units, Unit Conversions
- Topic: Chemical Formulas [ENDORSED]
- Replies: 11
- Views: 1021
Re: Chemical Formulas [ENDORSED]
Hi, I was just wanted to know... to what extent should we know chemical formulas? It is not necessary as he will provide us with the formula. However, I recommend knowing the chemical formulas for basic elements such as carbon, Hydrogen, Oxygen, Nitrogen, sulfur, and potassium because most chemical...
- Sun Apr 15, 2018 5:57 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Atomic weight vs molecular weight
- Replies: 4
- Views: 959
Re: Atomic weight vs molecular weight
As mentioned above, atomic weight refers to the weight of a single atom. The molecular weight is the weight of a molecule such as sugar, (C6H12O6). These terms are needed to solve basic chemistry such as finding the molar mass of a molecule, balancing chemical equations, empirical and molecular form...
- Sun Apr 15, 2018 5:51 pm
- Forum: Empirical & Molecular Formulas
- Topic: Determining Formulas Based on Molecule
- Replies: 4
- Views: 652
Re: Determining Formulas Based on Molecule
The definition of molecular formula is the actual formula of the molecule.Therefore, counting the number of each element should be fine if you are looking to find the molecular formula. The molecular formula has the smallest possible numbers that you are able to simplify. If you have C4H8O2, it can ...