Search found 50 matches
- Fri Dec 06, 2019 10:23 am
- Forum: Naming
- Topic: Polyatomic ions
- Replies: 2
- Views: 225
Re: Polyatomic ions
I think you should just for the sake of being well-versed and prepared for possible questions. I'm sure we should know the most basic ones as we are being tested on acids and bases as well as coordination compounds.
- Fri Dec 06, 2019 10:21 am
- Forum: Amphoteric Compounds
- Topic: Amphiprotic vs Amphoteric
- Replies: 5
- Views: 598
Re: Amphiprotic vs Amphoteric
An amphiprotic substance is an amphoteric substance that transfers H+ ions.
- Fri Dec 06, 2019 10:20 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Sig Figs in 6B3
- Replies: 3
- Views: 412
Re: Sig Figs in 6B3
Likely the two sig figs comes from the value of concentration 0.025 M.
- Fri Dec 06, 2019 10:17 am
- Forum: Trends in The Periodic Table
- Topic: Atomic Radius vs Ionic Radius
- Replies: 3
- Views: 415
Re: Atomic Radius vs Ionic Radius
The trend for ionic radius is the same for that of atomic radius, but the discrepancy is that when you go down a period towards nonmetals that form anions, the ionic radius jumps as anions are larger than cations, but then continues to follow the trend.
- Fri Dec 06, 2019 10:15 am
- Forum: Bronsted Acids & Bases
- Topic: Amphiprotic vs amphoteric
- Replies: 3
- Views: 285
Re: Amphiprotic vs amphoteric
An amphiprotic species refers to the characteristic of being able to act as both an acid and a base. Amphoteric refers to the same thing, but an amphiprotic substance is an amphoteric substance that transfers H+ ions.
- Sat Nov 30, 2019 3:55 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: Test 2 Number of Hydrogen Bonding Sites on Caffeine
- Replies: 2
- Views: 344
Re: Test 2 Number of Hydrogen Bonding Sites on Caffeine
The correct answer on my test was 9 hydrogen bonds.
- Sat Nov 30, 2019 3:41 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: [H3O+] and [OH-]
- Replies: 3
- Views: 278
Re: [H3O+] and [OH-]
I believe H3O+ is just another way to represent H+ ions in water. I believe [H3O+] is equivalent to the [H+].
- Sat Nov 30, 2019 3:39 pm
- Forum: Hybridization
- Topic: Pi vs Sigma Bonds
- Replies: 10
- Views: 665
Re: Pi vs Sigma Bonds
Victoria Otuya 4F wrote:Are sigma single bonds, and pi double bonds? I am confused on how to count those bonds?
A single bond is a sigma bond. A double bond has a sigma bond and a pi bond. A triple bond has a sigma bond and two pi bonds.
- Sat Nov 30, 2019 3:37 pm
- Forum: Biological Examples
- Topic: Cisplatin
- Replies: 3
- Views: 282
Re: Cisplatin
I think it would be best to just memorize whatever you can. I know someone who said cisplatin showed up on their final last year. Just memorize whatever you can just in case.
- Sat Nov 30, 2019 3:32 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Relative Acidity
- Replies: 4
- Views: 358
Re: Relative Acidity
An anion is more stable when it has a higher electronegativity and thus attracts more electrons. This means an anion that is more polarizable is also more stable.
- Sun Nov 24, 2019 4:24 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Substitution reaction
- Replies: 1
- Views: 173
Re: Substitution reaction
A substitution reaction is a reaction in which one functional group in a chemical compound is replaced by another functional group. This kind of reaction has great biological significance.
- Sun Nov 24, 2019 4:21 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: acids
- Replies: 4
- Views: 346
Re: acids
Not all bases have OH-. Ammonia, NH3 is a base, but is accepts an H+ therefore it is a base.
- Sun Nov 24, 2019 4:18 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligands
- Replies: 2
- Views: 228
Re: Ligands
A ligand is a molecule, atoms or ion that is bound to a central atom.
- Sun Nov 24, 2019 4:11 pm
- Forum: Hybridization
- Topic: Hybrid orbitals
- Replies: 5
- Views: 339
Re: Hybrid orbitals
You look at the Lewis structure and count the number of atoms and lone pairs bonded to the central atoms to determine hybrid orbitals.
- Sun Nov 24, 2019 3:57 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Number
- Replies: 3
- Views: 257
Re: Coordination Number
It is the number of molecules, ions, or atoms bound to the central atom. The surrounding molecules, ions, or atoms are called ligands.
- Sun Nov 17, 2019 2:46 pm
- Forum: Trends in The Periodic Table
- Topic: Question
- Replies: 17
- Views: 1421
Re: Question
Can someone explain the exception for oxygen and nitrogen? It was on the midterm and I got it wrong. According to the trend, oxygen should have a higher ionization energy than nitrogen. However, nitrogen has its p-subshell half-filled and is relatively stable and low energy. Oxygen has one more ele...
- Sun Nov 17, 2019 2:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw
- Replies: 23
- Views: 1053
Re: Seesaw
You're definitely right; the lone pair should cause enough repulsion to distort the angles at least slightly in comparison to the bond angles of a trigonal bipyramidal molecule. I assume that's where the "approximately" 90º and 120º comes in?
- Sun Nov 17, 2019 2:31 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR notation
- Replies: 8
- Views: 554
Re: VSEPR notation
The formula would be AX3 because there are three regions of electron density surrounding the central atom. They are all bonded pairs of electrons, so the formula would include X3. If any of the regions of electron density included lone pairs of electrons, you would have to use the E part of the form...
- Sun Nov 17, 2019 2:23 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Trigonal Pyramidal?
- Replies: 4
- Views: 330
Re: Trigonal Pyramidal?
I believe if the molecule has four regions of electron density, then it cannot be trigonal planar. If it has four regions of electron density, three of which are bonded pairs, then the molecule would be called trigonal pyramidal.
- Sun Nov 17, 2019 2:21 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Angles less than 109.5 degrees
- Replies: 5
- Views: 740
Re: Angles less than 109.5 degrees
Trigonal planar and trigonal pyramidal are not the same thing, even though each have three bonding pairs. Trigonal pyramidal has three bonding pairs and an additional lone pair, making a total of four regions of electron density. The lone pair causes repulsion, pushing the bonded pairs away from one...
- Sat Nov 09, 2019 3:42 pm
- Forum: SI Units, Unit Conversions
- Topic: Memorizing Conversions
- Replies: 25
- Views: 1378
Re: Memorizing Conversions
Most common conversions are available on the equation and constants sheet and most likely there won't be any problems that require an arbitrary conversion not given on the sheet.
- Sat Nov 09, 2019 3:40 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarisability vs Polarizing Power
- Replies: 15
- Views: 1170
Re: Polarisability vs Polarizing Power
Polarizability is for atoms that tend to form anions and have larger electron clouds and it measures how much those electron clouds can be distorted. Polarizing power is for the cations that have the nuclear power to distort electron clouds of other atoms.
- Sat Nov 09, 2019 3:37 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarisability
- Replies: 3
- Views: 237
Re: Polarisability
Larger molecules have more electron repulsion and larger electron clouds and are therefore more prone to distortion than smaller molecules.
- Sat Nov 09, 2019 3:23 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Distorted e- as highly polarizable
- Replies: 5
- Views: 492
Re: Distorted e- as highly polarizable
Electrons can be distorted when there is a nearby atom that has a higher polarizing power that pulls on the electron cloud, introducing distortion.
- Sat Nov 09, 2019 3:21 pm
- Forum: Ionic & Covalent Bonds
- Topic: Bond Strength
- Replies: 12
- Views: 1099
Re: Bond Strength
Ionic bonds are stronger than covalent bonds because of the larger difference in electronegativity.
- Sun Nov 03, 2019 12:23 pm
- Forum: Lewis Structures
- Topic: Central Atom
- Replies: 3
- Views: 99
Re: Central Atom
The central atom tends to be the least electronegative and the one with the most unpaired valence electrons.
- Sun Nov 03, 2019 12:22 pm
- Forum: Electronegativity
- Topic: Relation between Electronegativity and ionization energy
- Replies: 3
- Views: 167
Re: Relation between Electronegativity and ionization energy
Electronegativity is the measure of the attraction of electrons to a certain atom. Therefore, electronegativity influences both electron affinity, the energy released when an electron is added to an atom, and ionization energy, the energy requires to remove an electron.
- Sun Nov 03, 2019 12:17 pm
- Forum: Lewis Structures
- Topic: Bonds
- Replies: 4
- Views: 154
Re: Bonds
Also, often you will be shifting around with the different types of bonds when drawing the various resonance structures for a compound. This usually entails removing double or triple bonds and turning them into single bonds and adding formal charges.
- Sun Nov 03, 2019 12:13 pm
- Forum: Bond Lengths & Energies
- Topic: Strength related to reactivity
- Replies: 2
- Views: 200
Re: Strength related to reactivity
Longer bonds are weaker than shorter bonds and are therefore easier to break. Also, single bonds are longer than double bonds.
- Sun Nov 03, 2019 12:12 pm
- Forum: Lewis Structures
- Topic: Formal charges on structures
- Replies: 2
- Views: 1588
Re: Formal charges on structures
Yes, the most stable resonance structures or Lewis diagrams in general include as many formal charges of 0 as possible.
- Fri Oct 25, 2019 8:46 am
- Forum: Trends in The Periodic Table
- Topic: Aufbau Principle
- Replies: 11
- Views: 615
Re: Aufbau Principle
Micah3J wrote:What kind of questions might there be regarding the Aufbau Principle on a test?
The Aufbau Principle is mostly applied to writing out electron configurations for atoms of different elements.
- Fri Oct 25, 2019 8:43 am
- Forum: Ionic & Covalent Bonds
- Topic: ionization
- Replies: 8
- Views: 301
Re: ionization
Why is the second ionization energy of an element always higher?? Ionization energy is the energy required to remove an electron from an atoms. The second ionization energy is the energy required to remove an electron from a cation with a +1 charge. In this cation, there is already one more proton ...
- Fri Oct 25, 2019 8:40 am
- Forum: Trends in The Periodic Table
- Topic: week 4 Hw problems
- Replies: 4
- Views: 250
Re: week 4 Hw problems
I just want to clarify that we can still turn in quantum world hw questions as the 5 questions due in section? I have them done and don't want to find out later that I won't get credit. Homework can be any problem you want but it would be better if it is from the topic we're covering in class simul...
- Fri Oct 25, 2019 8:37 am
- Forum: Resonance Structures
- Topic: Resonance Structures
- Replies: 4
- Views: 171
Re: Resonance Structures
Resonance structures are essentially all the ways one molecule can be represented using a Lewis structure. The real molecule that exists is actually a blend of all the possible structures. I think most likely you would be required to always consider resonance and draw as many structures as you can.
- Fri Oct 25, 2019 8:34 am
- Forum: Lewis Structures
- Topic: Where to start putting dots for electrons
- Replies: 10
- Views: 594
Re: Where to start putting dots for electrons
If an atom, such as oxygen, forms a double bond and has two lone pairs of electrons, should I draw the dots for the lone pairs on diagonal sides of the O (on the other side of the double bond lines), rather than on the top and the bottom? Personally, I like placing the lone pairs on the top and bot...
- Sun Oct 20, 2019 11:20 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Hund's Rule
- Replies: 5
- Views: 282
Re: Hund's Rule
The electrons cannot pair up first because they would repel one another, so the lowest energy scenario is if one electron fills up the orbitals first.
- Sun Oct 20, 2019 11:13 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Spin Quantum Number
- Replies: 3
- Views: 207
Re: Spin Quantum Number
Also, this spin number is important to know because it determines whether or not an atom can generate a magnetic field.
- Sun Oct 20, 2019 11:11 pm
- Forum: Properties of Electrons
- Topic: What's the difference between a shell, a subshell, an energy level, and an orbital?
- Replies: 8
- Views: 620
Re: What's the difference between a shell, a subshell, an energy level, and an orbital?
The Principle Quantum Number (n) refers to the subshell. The orbital angular momentum quantum number l determines the shape of the orbital and the magnetic quantum number m(l) indicates how many orbitals there are in the subshell. Energy level is just a broader term for subshell.
- Sun Oct 20, 2019 11:07 pm
- Forum: Trends in The Periodic Table
- Topic: Electron affinity
- Replies: 5
- Views: 342
Re: Electron affinity
Electron affinity is essentially the amount of energy released when an electron is added to a neutral atom in the gaseous state. Electron affinity increases as you go up the periodic table as well as when you go left to right on the periodic table. The added electrons become closer to the nucleus, c...
- Sun Oct 20, 2019 11:04 pm
- Forum: *Shrodinger Equation
- Topic: Z^2 in Schrodinger Equation
- Replies: 2
- Views: 632
Re: Z^2 in Schrodinger Equation
I believe what it is trying to say is that the strength of the nucleus pulling in the electrons is Z^2, which means that as the atomic number number increases, the nuclear charge Ze increases by the factor of Z^2.
- Sat Oct 12, 2019 2:48 pm
- Forum: DeBroglie Equation
- Topic: De Broglie's Equation
- Replies: 13
- Views: 572
Re: De Broglie's Equation
De Broglie's equation concerns the variables of wavelength, velocity, and mass of an electron, as well as Planck's constant. The equation is used to describe the wave-like properties of elementary particles (including electrons), neutral atoms and molecules.
- Sat Oct 12, 2019 2:43 pm
- Forum: Properties of Light
- Topic: Equations
- Replies: 4
- Views: 165
Re: Equations
I think it is also important to mention that a lot of the equation we have discussed in this unit concern many of the same variables such as wavelength and frequency and you can use multiple equations or a combination of them to find the value you need.
- Sat Oct 12, 2019 2:32 pm
- Forum: Limiting Reactant Calculations
- Topic: Wrong calculation-can' find the Lim. Reactant
- Replies: 2
- Views: 266
Re: Wrong calculation-can' find the Lim. Reactant
Well, considering how far you've gotten, you know that NH3 is the limiting reactant for the reaction. So you would use the mole ratio between NH3 and NO multiply by the molar mass of NO to determine how many grams of NO are produced. You would do the same for H2O.
- Sat Oct 12, 2019 2:23 pm
- Forum: Properties of Light
- Topic: difference between Rydberg equation and De Broglie equation
- Replies: 5
- Views: 534
Re: difference between Rydberg equation and De Broglie equation
De Broglie's equation is used to describe the wave properties of matter, whereas Rydberg's equation is used to calculate the wavelength of a light emitted from an electron that moves between energy levels.
- Sat Oct 12, 2019 2:15 pm
- Forum: Properties of Light
- Topic: Amplitude
- Replies: 12
- Views: 577
Re: Amplitude
What is the relationship between amplitude and intensity of light? According to the same website as the comment above,"The intensity of a wave is proportional to the square of its amplitude." It's more of a physics concept so it's not likely that amplitude will be relevant to calculations...
- Thu Oct 03, 2019 11:02 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Does the state of matter mean anything right now?
- Replies: 4
- Views: 141
Re: Does the state of matter mean anything right now?
I apologize for adding on to the initial question, but does anyone know if we will get points taken off of homework or exams if we do not put the state of matter next to the substances when writing a chemical equation? I don't know about points, although I expect in the future when we have to write...
- Thu Oct 03, 2019 11:00 pm
- Forum: Limiting Reactant Calculations
- Topic: Limiting Reactant problems
- Replies: 4
- Views: 174
Re: Limiting Reactant problems
He basically mentioned this just to demonstrate an example of why the actual, experimental yield of a certain reaction may be lower than the theoretical, calculated yield. It's not something we calculate, just a possible justification for the discrepancy between the actual and theoretical yield. If ...
- Thu Oct 03, 2019 10:53 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Does the state of matter mean anything right now?
- Replies: 4
- Views: 141
Re: Does the state of matter mean anything right now?
No, as far as I know, the state of matter doesn't influence the balancing of chemical reactions; it's just more of an introduction to more complex chemistry concepts we're likely to learn soon.
- Thu Oct 03, 2019 10:50 pm
- Forum: Balancing Chemical Reactions
- Topic: How to Balance A Chemical Reaction
- Replies: 7
- Views: 426
Re: How to Balance A Chemical Reaction
Ok so this is how I'd approach it. I want to balance Fe first, so I add 2 in front of the product Fe to get Fe2O3 + CO >> 2Fe + CO2. Then, it seems like there are 4 O atoms on the reactants side and 2 on the products side, so it seems natural the 2 goes in front of the CO2. However, like you did, wh...
- Thu Oct 03, 2019 10:41 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Avogadro's Number?
- Replies: 16
- Views: 960
Re: Avogadro's Number?
Do you think we will have to memorize the Avogadro's Number for test? I am wondering if I will be given the Avogadro's Number when I get the questions that ask for atoms' number. I don't know if we'll be given the number but honestly we use Avogadro's number often enough in calculations that it'll ...