Search found 56 matches
- Sun Dec 08, 2019 8:38 pm
- Forum: Lewis Acids & Bases
- Topic: bases
- Replies: 5
- Views: 507
Re: bases
Strong bases dissociate completely in solution whereas weak bases do not. Typically, the reaction for a strong base has a single arrow indicating only a forward reaction, which makes sense since strong bases dissociate completely in solution.
- Sun Dec 08, 2019 8:35 pm
- Forum: Lewis Acids & Bases
- Topic: What does it mean when something is strong?
- Replies: 8
- Views: 614
Re: What does it mean when something is strong?
Strong acids and bases have weaker bonds between the molecules, which means that they dissociate completely in solution
- Sun Dec 08, 2019 8:34 pm
- Forum: Biological Examples
- Topic: Cisplatin [ENDORSED]
- Replies: 19
- Views: 1325
Re: Cisplatin [ENDORSED]
Cisplatin is a chemotherapy drug, and it binds to the nucleotides on DNA to stop cell growth; however, in doing so, it stops the production of normal cells.
- Sun Dec 08, 2019 8:31 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: boiling point
- Replies: 9
- Views: 950
Re: boiling point
Substances that have a higher boiling point are more polar and greater IMF, such as dipole-dipole interactions, LDFs, hydrogen bonds, ion-ion, and dipole-induced-dipole.
- Sun Dec 08, 2019 8:28 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Stronger acid?
- Replies: 13
- Views: 1224
Re: Stronger acid?
To find out which one is the stronger acid between HClO and HClO2, look at the number of oxygens. Because both molecules have a H and Cl, it falls onto the number of O to determine which is the stronger acid. The general rule is the greater number of O's, the stronger the acid. This is because the o...
- Sun Dec 08, 2019 8:24 pm
- Forum: Dipole Moments
- Topic: Hydrogen bonds
- Replies: 9
- Views: 600
Re: Hydrogen bonds
A hydrogen bond is between a H and an N, O, and F. Potential bonding sites are on the lone pairs of N, O, and F.
- Mon Dec 02, 2019 12:07 am
- Forum: Conjugate Acids & Bases
- Topic: Conjugate Acids and Bases
- Replies: 4
- Views: 413
Re: Conjugate Acids and Bases
A conjugate acid of a base is the species formed when the base accepts a proton; a conjugate base of an acid is the species formed when the acid donates a proton. Basically, identify the acids and bases in the reactants. Then, look for the species that has an H+ now and didn't have it before–that's ...
- Mon Dec 02, 2019 12:00 am
- Forum: Lewis Acids & Bases
- Topic: Definition
- Replies: 7
- Views: 573
Re: Definition
A Lewis acid is an electron-pair acceptor and Lewis base is an electron-pair donor.
- Sun Dec 01, 2019 11:59 pm
- Forum: Biological Examples
- Topic: cisplatin
- Replies: 3
- Views: 224
Re: cisplatin
Cisplatin is a chemotherapy drug used to treat cancer. Be sure not to confuse it with transplatin, which has the Cl atoms diagonally across from each other. Cisplatin has the Cl atoms on the same side, which is useful in stopping cell growth and metastasizing cancer.
- Sun Dec 01, 2019 11:43 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Relative Acidity
- Replies: 4
- Views: 247
Re: Relative Acidity
Delocalizing the charge makes the molecule more stable. For instance, between HClO and HClO4, HClO4 would be the stronger acid since it has more oxygens to delocalize the charge. In terms of these molecules too, the greater number of oxygen atoms attached to the central atom makes the molecule a str...
- Fri Nov 29, 2019 3:28 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Carboxylic Acids
- Replies: 5
- Views: 505
Carboxylic Acids
Why are all carboxylic acids weak in water?
- Tue Nov 26, 2019 6:30 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligand of HN(CH2CH2NH2)2
- Replies: 1
- Views: 178
Ligand of HN(CH2CH2NH2)2
How is HN(CH2CH2NH2)2 tridentate? Is there anyway to think about this without drawing the Lewis structure?
- Mon Nov 25, 2019 9:00 pm
- Forum: Hybridization
- Topic: Hybridization of PF5
- Replies: 4
- Views: 2013
Hybridization of PF5
The hybridization of the central atom, P, is sp3d because it's shape is trigonal bipyramidal. What is the hybridization of the terminal atoms, F?
- Mon Nov 25, 2019 6:38 pm
- Forum: Hybridization
- Topic: Promotion Energy of Nitrogen, Oxygen, and Fluorine
- Replies: 1
- Views: 187
Promotion Energy of Nitrogen, Oxygen, and Fluorine
Why can't nitrogen, oxygen, and fluorine use promotion energy to increase the number of bonds it can form? I know it has to do with no empty p-orbitals, but what does that specifically mean?
- Mon Nov 25, 2019 6:35 pm
- Forum: Hybridization
- Topic: Tetravalence of Carbon
- Replies: 3
- Views: 240
Tetravalence of Carbon
How is carbon tetravalent? Also, how does this relate to promotion energy?
- Mon Nov 25, 2019 2:37 pm
- Forum: Bronsted Acids & Bases
- Topic: Arrhenius, Bronsted, and Lewis
- Replies: 1
- Views: 174
Arrhenius, Bronsted, and Lewis
What are the differences between Arrhenius, Bronsted, and Lewis acids and bases?
- Mon Nov 25, 2019 2:34 pm
- Forum: Biological Examples
- Topic: Cisplatin [ENDORSED]
- Replies: 19
- Views: 1325
Re: Cisplatin [ENDORSED]
Cisplatin is used in chemotherapy to stop the growth of cancer cells. In the process, it damages DNA and prevents DNA synthesis, which in turn damage the healthy cells.
- Mon Nov 25, 2019 2:26 pm
- Forum: Amphoteric Compounds
- Topic: Amphiprotic
- Replies: 11
- Views: 612
Re: Amphiprotic
Amphiprotic describes a molecule that can act as a proton donor and as a proton acceptor, such as water. Amphoteric describes a molecule that can react with both acids and bases.
- Wed Nov 20, 2019 3:20 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: N2O Lewis Structure/Pi and Sigma Bonds
- Replies: 2
- Views: 794
N2O Lewis Structure/Pi and Sigma Bonds
In N2O, why is N the central atom instead of O? Also, how many sigma and pi bonds are in this molecule?
- Tue Nov 19, 2019 9:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Instantaneous Dipole Moment
- Replies: 4
- Views: 375
Instantaneous Dipole Moment
What is an instantaneous dipole moment and what does it have to do with London forces?
- Tue Nov 19, 2019 4:56 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Structure of HCN
- Replies: 2
- Views: 282
Structure of HCN
Why is C the central atom in HCN? If N was the central atom, there would be formal charges on N and C, which means that it isn't the most stable structure. So, how do we know that C is the central atom?
- Mon Nov 18, 2019 6:00 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bonds in VSEPR
- Replies: 11
- Views: 644
Re: Bonds in VSEPR
Double, single, and triple bonds are considered one unit, which means that it accounts for one area of electron density even though there might be more bonds being used.
- Mon Nov 18, 2019 5:58 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: AXE notation
- Replies: 10
- Views: 683
Re: AXE notation
AXE is the generic VSEPR formula, and it helps identify molecular shapes based on the combinations of atoms and lone pairs attached to the central atom. In this formula, A represents is the central atom, X is the attached atoms, and E is the lone pairs present. By understanding this formula, you can...
- Mon Nov 18, 2019 5:55 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Notation
- Replies: 7
- Views: 416
Re: VSEPR Notation
When there are no lone pairs, there will be no E in the notation
- Wed Nov 13, 2019 1:14 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR model
- Replies: 4
- Views: 378
Re: VSEPR model
VSEPR stands for Valence-Shell Electron-Pair Repulsion, and it extends Lewis's theory by adding rules that explain bond angles and molecular shapes brought on by lone pairs. According to this model, regions of high electron density repel one another and these regions move to the most distant locatio...
- Tue Nov 12, 2019 11:30 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Single/Double Bonds in Resonance
- Replies: 6
- Views: 393
Single/Double Bonds in Resonance
Because single and double bonds are considered one unit in the VSEPR model, does it matter which of the Lewis structures contribute to the resonance structure? What's an example of this?
- Mon Nov 11, 2019 12:49 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs and Molecular Shape
- Replies: 3
- Views: 265
Lone Pairs and Molecular Shape
In a molecule with lone pairs, the valence electrons play a role in electron arrangement about the central atom. How do lone pair electrons distort the shape of a molecule?
- Mon Nov 11, 2019 12:47 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: H2O and Ionic Compounds
- Replies: 3
- Views: 208
H2O and Ionic Compounds
Why is water a good solvent for ionic compounds? I understand that water's polarity plays a factor but what does that mean and is there anything else that makes it a good solvent for ionic compounds?
- Mon Nov 11, 2019 12:45 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Diatomic Molecules
- Replies: 6
- Views: 388
Diatomic Molecules
Why are all diatomic molecules composed of two different elements at least slightly polar?
- Mon Nov 11, 2019 12:41 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Difference Between Lewis Structure and VSEPR Model
- Replies: 3
- Views: 7448
Difference Between Lewis Structure and VSEPR Model
What are the differences between lewis structures and VSEPR model? Also, what are the rules when doing VSPER models and is there an easy way of thinking about them?
- Mon Nov 11, 2019 12:39 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Determining Bond Angles
- Replies: 2
- Views: 204
Determining Bond Angles
How do you find the bond angles of molecules that are not fixed by symmetry? By extension, how was H2O's bond angle found?
- Sun Nov 03, 2019 6:04 pm
- Forum: Electronegativity
- Topic: What is isoelectronic?
- Replies: 13
- Views: 795
Re: What is isoelectronic?
Atoms and ions with equal number of electrons are isoelectronic. Examples include Na+, F-, and Mg2+. Be cautious, however, as these three ions have the same electron configuration (same number of electrons) but their radii differ because they have different nuclear charges. This means that the Mg2+ ...
- Sun Nov 03, 2019 5:53 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Dilution Equation
- Replies: 4
- Views: 306
Re: Dilution Equation
It depends on what the question is asking. For example, if the question is asking for V2 in mL, then it keep V1 in mL. Likewise, if the question is looking for V2 in L, then convert V1 to L. Be sure to stay consistent with your units as you're solving.
- Sun Nov 03, 2019 5:46 pm
- Forum: Octet Exceptions
- Topic: Biological Impacts of Radicals
- Replies: 4
- Views: 162
Biological Impacts of Radicals
From lecture, we know that radicals are exceptions to the octet rule because they have an odd number of electrons, which makes the octet formation numerically impossible, as well as having electrons with unpaired spins, overall making the molecule unstable and highly reactive. In the body, these rad...
- Sun Nov 03, 2019 5:40 pm
- Forum: Octet Exceptions
- Topic: radical
- Replies: 5
- Views: 445
Re: radical
The octet rule is a general rule of thumb, stating that each atom seeks to have eight valence electrons in its outermost shell. Exceptions to this rule include molecules with an odd number of electrons, which means that the octet formation is numerically impossible. This odd number of valence electr...
- Sun Nov 03, 2019 5:29 pm
- Forum: Trends in The Periodic Table
- Topic: Characteristics of Metallic and Nonmetallic Elements
- Replies: 2
- Views: 172
Characteristics of Metallic and Nonmetallic Elements
Because of periodic trends, we can predict, at least in a general sense, the properties of elements. With this in mind, what is the difference between metallic and nonmetallic elements, such as their physical and chemical properties? Is there any easy way or trick to memorizing/thinking about the di...
- Sun Oct 27, 2019 4:52 pm
- Forum: Resonance Structures
- Topic: Pointers For Appropriate Resonance Structures
- Replies: 2
- Views: 145
Pointers For Appropriate Resonance Structures
Besides understanding that a formal charge of 0 yields the most stable resonance structure, what other pointers are there for drawing structures and predicting which one contributes the most to the actual structure?
- Sun Oct 27, 2019 4:48 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Vs. Oxidation Number
- Replies: 4
- Views: 286
Formal Charge Vs. Oxidation Number
Formal charge and oxidation number both give the number of electrons in a compound; in that sense, they are similar conceptually. However, how are they different?
- Sun Oct 27, 2019 4:39 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge
- Replies: 5
- Views: 343
Re: Formal Charge
The formal charge of an atom is the measure of redistributed electrons in a Lewis structure. Essentially, it is the charge an atom would have if it shared a perfectly covalent bond with other atoms. To find formal charge, use the equation: FC=V–(L+S/2), where V represents the number of valence elect...
- Sun Oct 27, 2019 4:32 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Orbital Energies
- Replies: 1
- Views: 120
Orbital Energies
Why do p-electrons penetrate much less than s-electrons? What does this have to do with wave function, probability density, and shielding?
- Sun Oct 27, 2019 4:27 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Effective Nuclear Charge
- Replies: 4
- Views: 248
Effective Nuclear Charge
In multi-electron atoms, each electron is repelled by other present electrons. How do more electrons affect shielding and nuclear attraction?
- Sun Oct 20, 2019 10:23 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Quantum Numbers: Size of An Atom
- Replies: 4
- Views: 146
Quantum Numbers: Size of An Atom
The state of an electron is defined by n, l, Ml, and Ms. Why does the size of an atom increase as n increases?
- Sun Oct 20, 2019 10:16 pm
- Forum: Photoelectric Effect
- Topic: The Work Function
- Replies: 15
- Views: 1017
Re: The Work Function
The work function is the energy required to remove an electron from a metal, which means that the work function is not constant and changes depending on the metal used. In addition, the kinetic energy of an ejected electron is equal to the difference between the energy from the photon and the work f...
- Sun Oct 20, 2019 9:59 pm
- Forum: Properties of Light
- Topic: What are the units of hertz
- Replies: 41
- Views: 2118
Re: What are the units of hertz
Hz is a unit of frequency that denotes the number of complete cycles per second. 1 Hz=1/sec
- Sun Oct 20, 2019 9:56 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Stern & Gerlach Experiment
- Replies: 3
- Views: 233
Re: Stern & Gerlach Experiment
In this experiment, Stern and Gerlach initially pushed a narrow stream of silver atoms through a magnet to determine if the magnetic field would push atoms by different degrees based on the orientation of the electron's spin. This is what they observed at first, but it proved to be misleading since ...
- Sun Oct 20, 2019 9:30 pm
- Forum: Properties of Electrons
- Topic: Mass of an Electron
- Replies: 14
- Views: 560
Re: Mass of an Electron
9.109 x 10^-31 kg is the set mass of an electron, and we recognize this as a constant. This goes alongside the masses for protons and neutrons, which are about 1.67 x 10-27 kg each. These masses are constants as well.
- Sun Oct 13, 2019 9:03 pm
- Forum: Photoelectric Effect
- Topic: Wavelength, Frequency, and Intensity
- Replies: 7
- Views: 1166
Wavelength, Frequency, and Intensity
When discovering the photoelectric effect, why did short wavelengths (high frequencies) eject electrons but long wavelengths (low frequencies) couldn't? Also, why did the intensity of the light not matter?
- Sun Oct 13, 2019 8:56 pm
- Forum: Properties of Light
- Topic: Frequency, Wavelength, Amplitude, and Velocity
- Replies: 4
- Views: 180
Frequency, Wavelength, Amplitude, and Velocity
What is the relationship between frequency, wavelength, amplitude, and velocity (in terms of light, consider the speed of light)?
- Sun Oct 13, 2019 8:44 pm
- Forum: Einstein Equation
- Topic: Einstein's Equation
- Replies: 7
- Views: 313
Einstein's Equation
What does Ek=hv–Φ mean in terms of kinetic energy, electron ejection, intensity of the wave, and work function? Also, what interpretations were made from this equation regarding the photoelectric effect?
- Sun Oct 13, 2019 8:35 pm
- Forum: DeBroglie Equation
- Topic: Deriving De Broglie's Equation
- Replies: 2
- Views: 149
Deriving De Broglie's Equation
Using the equations c=λv, E=mc^2, and E=hv, how can you derive De Broglie's equation?
- Sun Oct 13, 2019 8:09 pm
- Forum: Photoelectric Effect
- Topic: Avogadro's number
- Replies: 7
- Views: 479
Re: Avogadro's number
Avogadro's number is used to find the number of objects, molecules, atoms, particles, etc. in one mol of an object. More specifically, there are 6.0221 x 10^23 objects in 1 mole of said objects. Mathematically, Avogadro's number is used in a ratio to convert the number of moles to the number of obje...
- Fri Oct 04, 2019 12:15 pm
- Forum: Balancing Chemical Reactions
- Topic: Fractions in front of compounds
- Replies: 12
- Views: 641
Re: Fractions in front of compounds
When you have a fraction as a stoichiometric coefficient, multiply both sides of the equation by the denominator of the fraction. For example, NH3 + O2 => NO + H2O, depending on the way you balance the equation, you might get: 2 NH3 + 5/2 O2 => 2 NO + 3 H2O In this case, you multiply both sides of t...
- Fri Oct 04, 2019 12:04 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Theoretical vs. Actual Yield
- Replies: 38
- Views: 14055
Re: Theoretical vs. Actual Yield
The actual yield for an experimental reaction is not equal to the theoretical yield because of side reactions that occur as well as impurities in the container that might hinder the reaction. Additionally, no reaction is ever 100% complete since the reactants don't completely react with each other, ...
- Fri Oct 04, 2019 2:14 am
- Forum: Empirical & Molecular Formulas
- Topic: Tips for Finding Which Number to Multiply a Decimal By to Get a Whole Number
- Replies: 10
- Views: 1176
Re: Tips for Finding Which Number to Multiply a Decimal By to Get a Whole Number
There isn't really a faster way of doing it, but it helps to think about it as simple as possible. For instance, if I'm trying to find a number to multiply 1.33 by to get a whole number, I think about what number can I multiply 3 to get a number roughly close to 10. In this case, multiplying 3 by 3 ...
- Fri Oct 04, 2019 1:56 am
- Forum: Empirical & Molecular Formulas
- Topic: When to know to multiply by a whole number when finding the empirical formula
- Replies: 5
- Views: 277
Re: When to know to multiply by a whole number when finding the empirical formula
I'm doing Fundamentals F.11 letter B and I was dividing 31.91 K/30.0983 and it gave me 1.060. I found the rest of the calculations for the other elements and I ended up dividing each of the numbers by the smallest number which was 0.8160. I got 1.299 for K. When do I know when to multiply to find a...
- Fri Oct 04, 2019 1:30 am
- Forum: Molarity, Solutions, Dilutions
- Topic: G 13
- Replies: 3
- Views: 373
Re: G 13
To solve this equation, use the dilution equation, M1V1=M2V2, in which M1 and V1 represent the initial molarity and the volume of the solution, respectively, and M2 and V2 represent the final molarity and volume, respectively. The problem provides M1 (0.2M NH4NO3), V1 (1L), and V2 (4L; because the f...