Search found 55 matches
- Wed Dec 04, 2019 3:52 pm
- Forum: Conjugate Acids & Bases
- Topic: Conjugate Acids and Bases
- Replies: 6
- Views: 1050
Re: Conjugate Acids and Bases
Conjugate acids and bases are bronsted acids and bases. They always appear in the same chemical reaction.
- Wed Dec 04, 2019 3:48 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Application of oxidation number
- Replies: 3
- Views: 446
Re: Application of oxidation number
Oxidation number is also useful when looking at redox reactions.
- Wed Dec 04, 2019 3:47 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: SO4
- Replies: 3
- Views: 377
Re: SO4
By putting the 4 oxygens around the sulfur, you immediately have an octet. If it comes without a charge, then don't add a charge.
- Wed Dec 04, 2019 3:43 pm
- Forum: Sigma & Pi Bonds
- Topic: finding hybridizations
- Replies: 2
- Views: 292
Re: finding hybridizations
If the electron is taken from n=2, then it's represented as 2sp^3, etc. If it's taken from n=3, then 3sp^3, etc.
In general, you can just represent it with sp^3.
In general, you can just represent it with sp^3.
- Wed Dec 04, 2019 3:41 pm
- Forum: Ionic & Covalent Bonds
- Topic: polarity of shapes
- Replies: 4
- Views: 433
Re: polarity of shapes
The bond angle would be less than the bond angles in a octahedral. The long pairs do affect the bond angle since they cause repulsion.
- Tue Nov 26, 2019 12:10 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: 9C.5
- Replies: 1
- Views: 171
Re: 9C.5
Polydentate is a ligand that binds at more than 1 site since it donates more than 1 e- pair.
You can draw out the lewis structure to figure out which atom has lone pairs.
a. 3, on the nitrogen atoms
b. 1 or 2 on oxygen atoms
c. not a polydentate
d. 2 on oxygen atoms
You can draw out the lewis structure to figure out which atom has lone pairs.
a. 3, on the nitrogen atoms
b. 1 or 2 on oxygen atoms
c. not a polydentate
d. 2 on oxygen atoms
Re: 9C.1
(a) Hexacyanoferrate (II) +2
(b) Hexaaminecobalt (III) +3
(c) Aquapentacyanocobalte (III) +3
(d) Pentaaminesulfatocobalt (III) +3
(b) Hexaaminecobalt (III) +3
(c) Aquapentacyanocobalte (III) +3
(d) Pentaaminesulfatocobalt (III) +3
- Tue Nov 26, 2019 12:06 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: 9C.3
- Replies: 4
- Views: 369
Re: 9C.3
Since there is a space between potassium and hexacyanidochromate (III), it indicates that potassium is out of the bracket.
K3 [Cr(CN)6]
K3 [Cr(CN)6]
- Tue Nov 26, 2019 12:03 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Shapes
- Replies: 4
- Views: 336
Re: Shapes
linear, square planar, tetrahedral, octahedral
Re: Rules
1. Put the ligand name in alphabetical order then put the transition metal cation name. 2. Use prefix to indicate the number of ligands: mono, di, tri, tetra, penta, hexa 3. Add O to the end of anion name: for example Cyanide -> Cyano 4. If ligand has name with di, tri, tetra, or polydentate, then u...
- Sat Nov 23, 2019 12:27 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: [Fe(CN)6]4-
- Replies: 5
- Views: 508
Re: [Fe(CN)6]4-
The total charge is given so that you can calculate the charge of the Fe ion. In this case, since the total charge of 4-, and CN has a charge of -1, the charge of the Fe ion is +2
- Sat Nov 23, 2019 12:25 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate
- Replies: 4
- Views: 219
Polydentate
What exactly is a polydentate?
- Sat Nov 23, 2019 12:23 pm
- Forum: Lewis Acids & Bases
- Topic: bronsted and lewis acids
- Replies: 2
- Views: 165
Re: bronsted and lewis acids
Bronsted acids are always lewis acids, but not all lewis acids are bronsted acids.
- Sat Nov 23, 2019 12:22 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis vs Bronsted
- Replies: 2
- Views: 218
Re: Lewis vs Bronsted
Also, although all bronsted acids are lewis acids, not all lewis acids are bronsted acids.
- Sat Nov 23, 2019 12:21 pm
- Forum: Lewis Acids & Bases
- Topic: carboxyl group COOH
- Replies: 3
- Views: 256
Re: carboxyl group COOH
It dissociates partially to release hydrogen ions
- Thu Nov 14, 2019 8:20 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Drawing Molecular Structures
- Replies: 8
- Views: 556
Re: Drawing Molecular Structures
You determine the VSEPR structure of the molecule first. Then you can use lines to represent atoms on the same plane with the paper, solid triangles as atoms coming towards you, and dashed lines as atoms going away from you.
- Thu Nov 14, 2019 8:19 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Formula
- Replies: 2
- Views: 215
Re: VSEPR Formula
Essentially yes. The number of bonded electron pairs represents X, and the number of lone pairs represets E.
Notice that a single bond, double bond, and triple bond all count towards a single X.
Notice that a single bond, double bond, and triple bond all count towards a single X.
- Thu Nov 14, 2019 8:16 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Trigonal Pyramid vs Trigonal Planar
- Replies: 6
- Views: 481
Re: Trigonal Pyramid vs Trigonal Planar
Also the bond angle is different. Trigonal planar has bond angles of 120 while trigonal pyramidal has bond angles of around 107, so these two are absolutely different.
- Thu Nov 14, 2019 8:15 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lewis Structures & VSEPR
- Replies: 9
- Views: 519
Re: Lewis Structures & VSEPR
Drawing lewis structures help you determine whether there are lone pairs or not, which influences the VSEPR structure. Thus to be safe, always draw out the VSEPR first.
- Thu Nov 14, 2019 8:14 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: varying VSEPRs
- Replies: 7
- Views: 475
Re: varying VSEPRs
Nope, because VSEPR relies on the lowest energy Lewis structure.
- Fri Nov 08, 2019 3:16 pm
- Forum: Photoelectric Effect
- Topic: Frequency and number of electrons ejected
- Replies: 2
- Views: 322
Frequency and number of electrons ejected
I know that to emit an electron, the photon has to reach a specific frequency. Is it true that the frequency of the photon has to double in order to emit the second electron?
- Fri Nov 08, 2019 3:12 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: DNA
- Replies: 3
- Views: 250
DNA
Why are there 2 hydrogen bonds between A and T base pairs?
- Fri Nov 08, 2019 3:11 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: Hydrogen bonding
- Replies: 4
- Views: 246
Hydrogen bonding
Does the H of H2O and O of CO form a hydrogen bond?
- Fri Nov 08, 2019 3:08 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical formula
- Replies: 3
- Views: 330
Re: Empirical formula
Remember that the key is to find the molar ratio of the elements. You find the number of moles of CO2, for example, through dividing the given grams by molar mass. This number of moles of CO2 is also the number of moles of C, since there is only 1 C atom in one CO2 molecule. For H2O, you need to tim...
- Fri Nov 08, 2019 3:01 pm
- Forum: Properties of Light
- Topic: Work Function
- Replies: 2
- Views: 214
Re: Work Function
Another way to think about it is that work function is the threshold energy need to emit one single electron from the metal. Thus the single photon needs to possess an adequate amount of energy, or at least the threshold energy.
- Sat Nov 02, 2019 12:14 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Energy change and Energy of photon
- Replies: 5
- Views: 369
Energy change and Energy of photon
If a hydrogen atom goes from n=3 to n=1, why is the change in energy negative and why is the energy of the photon emitted positive?
- Sat Nov 02, 2019 12:12 pm
- Forum: DeBroglie Equation
- Topic: Question about Converting Units
- Replies: 3
- Views: 140
Re: Question about Converting Units
1keV = 1000 eV
1 eV = 1.60e-19 J
so 1keV = 1000 x 1.60e-19 J
1 eV = 1.60e-19 J
so 1keV = 1000 x 1.60e-19 J
- Sat Nov 02, 2019 12:08 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Indeterminacy Equation
- Replies: 6
- Views: 545
Heisenberg Indeterminacy Equation
Where does the 4 pi come from in the equation?
- Sat Nov 02, 2019 12:05 pm
- Forum: Photoelectric Effect
- Topic: Work Function
- Replies: 6
- Views: 402
Work Function
What exactly is the definition of work function? If it's the energy needed to remove a single electron from solid metal, why is the unit sometimes J per mole?
- Sat Nov 02, 2019 12:01 pm
- Forum: Properties of Light
- Topic: Waves
- Replies: 4
- Views: 315
Re: Waves
As long as it's greater than 10^-15 m, then it's considered to have measurable wavelike properties.
- Fri Oct 25, 2019 2:36 pm
- Forum: Lewis Structures
- Topic: Drawing Lewis Structures
- Replies: 8
- Views: 269
Re: Drawing Lewis Structures
Hydrogen in some cases has lower ionization energy than other atoms. But it's almost never used as the central atom, except if the molecule is H2.
- Fri Oct 25, 2019 2:33 pm
- Forum: Lewis Structures
- Topic: Homework 2B.3 d
- Replies: 2
- Views: 122
Re: Homework 2B.3 d
First of all, BrF3 has a total of 28 valence electrons, instead of 24. Br has a lower ionization energy than F, so Br is the central atom. Each F-Br bond constitutes to 2 electrons, so that's a total of 6, and you still need to assign the rest of the 22 valence electrons. Put 4 electrons on Br so th...
- Fri Oct 25, 2019 2:29 pm
- Forum: Lewis Structures
- Topic: Charges on atoms with lower e- affinity
- Replies: 4
- Views: 149
Re: Charges on atoms with lower e- affinity
And by charge, he meant the calculated formal charge.
- Fri Oct 25, 2019 2:17 pm
- Forum: Octet Exceptions
- Topic: Octet exception examples
- Replies: 9
- Views: 305
Re: Octet exception examples
also P, S, Cl may exceed the octet rule
- Fri Oct 25, 2019 2:16 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Electron Affinity and Formal Charge
- Replies: 3
- Views: 152
Re: Electron Affinity and Formal Charge
Basically put the negative charge on the atom with the highest electron affinity
- Thu Oct 17, 2019 10:01 pm
- Forum: Properties of Light
- Topic: atomic spectra
- Replies: 2
- Views: 156
Re: atomic spectra
c = wavelength x frequency c= speed of light wavelength = 1850 nm (be sure to convert it to meters) You will get frequency. Plug the frequency value into E=hv, where h is planck's constant. You will get the energy of a single photon. Then use the total number of Energy, which is 11J, divide it by th...
- Thu Oct 17, 2019 9:56 pm
- Forum: Properties of Light
- Topic: 1A.9 Energy of Photon
- Replies: 12
- Views: 513
Re: 1A.9 Energy of Photon
E = hv
So after u calculate v from c=wavelength x frequency, u plug it into E=hv with h as Planck's constant
So after u calculate v from c=wavelength x frequency, u plug it into E=hv with h as Planck's constant
- Thu Oct 17, 2019 9:55 pm
- Forum: *Shrodinger Equation
- Topic: Nodal Planes
- Replies: 6
- Views: 359
Nodal Planes
How many nodal planes do f orbitals have?
- Thu Oct 17, 2019 9:54 pm
- Forum: *Shrodinger Equation
- Topic: Psi ^2
- Replies: 2
- Views: 102
Psi ^2
I know that psi represents the height of a wave at position x,y, z. But I don't understand why psi^2 represents the probability of finding an e-.
- Thu Oct 17, 2019 9:51 pm
- Forum: *Shrodinger Equation
- Topic: Quantum Number
- Replies: 2
- Views: 201
Quantum Number
If Schrodinger wave equation with 3 quantum numbers can only be used to solve for 1 e- atoms, then can you use 4 quantum numbers to solve for more electrons since the fourth number indicates the spin state?
- Wed Oct 09, 2019 4:11 pm
- Forum: Significant Figures
- Topic: %Mass Composition
- Replies: 12
- Views: 826
%Mass Composition
If we're asked to calculate the %mass composition of a compound, how many sig figs should we keep?
- Wed Oct 09, 2019 4:08 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Atomic Spectra
- Replies: 5
- Views: 182
Re: Atomic Spectra
Yea, as long as they are spectra of the same atom.
- Wed Oct 09, 2019 3:58 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Equation Question
- Replies: 2
- Views: 174
Re: Equation Question
Also this equation only applies to the H-atom
- Wed Oct 09, 2019 3:55 pm
- Forum: Photoelectric Effect
- Topic: Atomic Spectra [ENDORSED]
- Replies: 3
- Views: 130
Re: Atomic Spectra [ENDORSED]
It is grouped by the type of electromagnetic radiation or wavelength/frequency that is shone on the material. Thus it is grouped as UV, infrared, and visible and since they have different energies, the electrons will return to different shells.
- Wed Oct 09, 2019 3:48 pm
- Forum: Photoelectric Effect
- Topic: E=hv
- Replies: 1
- Views: 93
E=hv
If the question asks that a certain amount of energy is needed to remove 1 mole of electrons, you first divide the energy by Avogadro's number before proceeding to the rest of the calculation right?
- Sat Oct 05, 2019 6:13 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Which Volume to use for M1
- Replies: 6
- Views: 324
Re: Which Volume to use for M1
The first volume given usually allows you to calculate the molarity. Typically we use the second volume in the calculation.
- Sat Oct 05, 2019 6:10 pm
- Forum: Limiting Reactant Calculations
- Topic: Explaining why a reactant is limiting
- Replies: 4
- Views: 212
Re: Explaining why a reactant is limiting
I would write down my calculation first: 0.3moles / 2 = 0.15moles of B 0.2 moles /1 = 0.2 moles of A. Since 0.15 moles of B is less than 0.2 moles of A, B is the limiting reactant. I think your explanation is also acceptable, as long as you explain that since we only have .3 moles of B right now and...
- Sat Oct 05, 2019 6:03 pm
- Forum: Empirical & Molecular Formulas
- Topic: Combustion Analysis
- Replies: 6
- Views: 300
Re: Combustion Analysis
A combustion analysis allows you to deduce the formula of an organic compound, which is usually CxHy or CxHyOz. It can also be used to determine the percentage purity by mass of a given compound.
- Sat Oct 05, 2019 6:01 pm
- Forum: Empirical & Molecular Formulas
- Topic: Is there an easier way to figure out which integer to multiply the number of atoms with to get a whole number?
- Replies: 4
- Views: 240
Re: Is there an easier way to figure out which integer to multiply the number of atoms with to get a whole number?
You can convert it to a fraction first (using your calculator) then just multiply by the denominator.
- Sat Oct 05, 2019 6:00 pm
- Forum: Empirical & Molecular Formulas
- Topic: Combustion Analysis
- Replies: 1
- Views: 317
Combustion Analysis
Hey guys Im confused about M.26. It states that a combustion analysis of the compound C14H20O2N gave the following data: 68.50%C, 8.18%H by mass. Because the data were considerably different from that expected for pure C14H20O2N, the sample was examined and found to contain a significant amount of C...
- Sat Sep 28, 2019 4:32 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Avogradro's Number [ENDORSED]
- Replies: 5
- Views: 552
Avogradro's Number [ENDORSED]
So I was doing E5 on the textbook and it asks how many moles of people inhabit Earth if the estimated population is 7.0 billion people. This made me question the definition of 1 mole and Avogadro's number.
- Sat Sep 28, 2019 4:27 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: MOLARITY
- Replies: 17
- Views: 2170
Re: MOLARITY
Does anyone know the difference between molarity and molality?
- Sat Sep 28, 2019 4:23 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: mass of solute
- Replies: 3
- Views: 86
Re: mass of solute
Becuz ur asked to prepare a solution. When copper (ii) sulfate pentahydrate is dissolved in water, the attached H2O joins with the surrounding water. Since copper (ii) sulfate pentahydrate contains 1 mole of CuSO4, the amount of copper (ii) sulfate pentahydrate you need is the same as the amount of ...
- Sat Sep 28, 2019 4:10 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Formula Unit
- Replies: 7
- Views: 1116
Formula Unit
Could someone please explain the difference between a formula unit and a molecule? Thanks.
- Sat Sep 28, 2019 4:03 pm
- Forum: Significant Figures
- Topic: How does Significant Figures work? [ENDORSED]
- Replies: 12
- Views: 632
Re: How does Significant Figures work? [ENDORSED]
In inter-problem calculations, how many sig figs do u keep? Same as the question or one more?