Search found 61 matches
- Sun Mar 17, 2019 1:43 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Effects of Compression
- Replies: 5
- Views: 593
Effects of Compression
Compression of a reaction only has an effect if all of the agents are in gas phase right? Because that is the only way a difference in moles between the sides of the reaction would cause a pressure difference?
- Sat Mar 16, 2019 11:51 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Adding an Inert Gas
- Replies: 4
- Views: 592
Adding an Inert Gas
Will adding an inert gas cause a shift if it increases the overall pressure of the system? I mean, will it cause the reaction to shift towards the side that has less molecules or moles if there is one?
- Sat Mar 16, 2019 10:12 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Partial Pressures
- Replies: 3
- Views: 500
Partial Pressures
When applying Le Chateliers to partial pressures, should we think about it in terms of compressing the entire reaction or changing the amount of a given reactant or product present?
- Sat Mar 16, 2019 10:08 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Molecular Interlude
- Replies: 5
- Views: 815
Re: Molecular Interlude
Hope you figured it out!
- Sat Mar 16, 2019 10:06 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: HW problem 4B. 13
- Replies: 5
- Views: 898
Re: HW problem 4B. 13
Hope this helped!
- Sat Mar 16, 2019 10:05 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Pure Solids and Liquids
- Replies: 4
- Views: 694
Re: Pure Solids and Liquids
Thank you guys for your responses!
- Sat Mar 16, 2019 10:04 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Term Differences (Heat, Enthalpy, Temperature, and Work)
- Replies: 4
- Views: 802
Re: Term Differences (Heat, Enthalpy, Temperature, and Work)
Hope this helped you understand the concepts better!
- Sat Mar 16, 2019 10:00 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Negative pH
- Replies: 12
- Views: 1522
Re: Negative pH
Thanks for all your responses!
- Sat Mar 16, 2019 9:59 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Enthalpy of Vaporization
- Replies: 2
- Views: 450
Re: Enthalpy of Vaporization
Thank you!
- Sat Mar 16, 2019 9:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K and Kc
- Replies: 6
- Views: 935
Re: K and Kc
Hope this helps!
- Sat Mar 16, 2019 9:57 pm
- Forum: Calculating Work of Expansion
- Topic: Units
- Replies: 5
- Views: 703
Re: Units
Thank you!
- Sat Mar 16, 2019 9:54 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K and Kc
- Replies: 6
- Views: 935
Re: K and Kc
K can be used interchangeably to refer to the equilibrium constant using partial pressures or concentration. Sometimes you will see Kp when using partial pressures or Kc when using concentrations. If there is no subscript, partial pressures are probably being used, but you should be able to tell bas...
- Sat Mar 16, 2019 9:51 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: [H2O] omitted??
- Replies: 2
- Views: 624
Re: [H2O] omitted??
Yes, because it is in such large excess
- Sat Mar 16, 2019 9:50 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Free Expansion
- Replies: 3
- Views: 669
Re: Free Expansion
This means that no energy was put into the system to initiate expansion
- Sat Mar 16, 2019 9:48 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Effect of increased concentration on equilibrium
- Replies: 9
- Views: 1463
Re: Effect of increased concentration on equilibrium
Hope this helped!
- Sat Mar 16, 2019 9:47 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Question 5G
- Replies: 3
- Views: 638
Re: Question 5G
Hope you figured it out!
- Sun Feb 10, 2019 9:30 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Midterm 2019
- Replies: 9
- Views: 866
Re: Midterm 2019
The midterm covers everything through the end of entropy in Outline 4
- Sun Feb 10, 2019 9:27 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Term Differences (Heat, Enthalpy, Temperature, and Work)
- Replies: 4
- Views: 802
Re: Term Differences (Heat, Enthalpy, Temperature, and Work)
Heat is actually kind of difficult to define but I think the best way I've heard it described is the energy that is exchanged between a system and it's surroundings due to a difference in pressure. Temperature is just a scale we use to measure the intensity of heat which is why we often use degrees ...
- Sun Feb 10, 2019 8:38 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Molecular Interlude
- Replies: 5
- Views: 815
Re: Molecular Interlude
I think anything of that nature that we would need on a test would be given to us.
- Tue Feb 05, 2019 9:55 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Enthalpy of Vaporization
- Replies: 2
- Views: 450
Enthalpy of Vaporization
Would we find an enthalpy of vaporization of a substance essentially the same way we find heat capacity?
- Tue Feb 05, 2019 9:32 pm
- Forum: Calculating Work of Expansion
- Topic: Units
- Replies: 5
- Views: 703
Re: Units
I guess I just don't understand how, when using pdeltav, atm(L) gives us joules
- Tue Feb 05, 2019 9:24 pm
- Forum: Calculating Work of Expansion
- Topic: Units
- Replies: 5
- Views: 703
Units
When we're using the ideal gas law or calculating work of expansion in general, what units of pressure and volume should we be using?
- Tue Feb 05, 2019 9:11 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: HW problem 4B. 13
- Replies: 5
- Views: 898
Re: HW problem 4B. 13
We use the second equation when the external pressure is not constant, so in any reversible process
- Tue Jan 15, 2019 9:17 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Negative pH
- Replies: 12
- Views: 1522
Negative pH
Can be pH be negative? If the concentration of H+ is over 1, then the -log of it would be negative right?
- Tue Jan 15, 2019 8:16 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Question on 6th Edition 6A.21
- Replies: 2
- Views: 233
Re: Question on 6th Edition 6A.21
That makes sense. Thank you!
- Tue Jan 15, 2019 8:07 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Question on 6th Edition 6A.21
- Replies: 2
- Views: 233
Question on 6th Edition 6A.21
How do I find [H3O+] with Kw and temperature given?
- Sun Jan 13, 2019 9:48 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Pure Solids and Liquids
- Replies: 4
- Views: 694
Pure Solids and Liquids
I still don't quite understand why we discount pure solids and liquids. Can someone help explain?
- Sun Jan 13, 2019 9:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Effect of increased concentration on equilibrium
- Replies: 9
- Views: 1463
Re: Effect of increased concentration on equilibrium
More product will be produced until equilibrium of concentrations is restored.
- Sun Jan 13, 2019 9:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Question 5G
- Replies: 3
- Views: 638
Re: Question 5G
Which question in 5G are you talking about?
- Sun Dec 09, 2018 1:01 am
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Strong/weak acids and bases
- Replies: 2
- Views: 321
Re: Strong/weak acids and bases
If it is an acid like HF or HCl, the easiest thing to look at is atomic radius, Cl has a larger atomic radius therefore the bond to the H is longer and weaker, making it more likely to donate the H. That makes it a stronger acid. The other thing to look for is resulting ion stability. Once the proto...
- Sun Dec 09, 2018 12:41 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Test 3 6b
- Replies: 2
- Views: 515
Re: Test 3 6b
Polarizing power has to do with the strength of the nuclear charge. Smaller atoms have higher polarizing power because there is less shielding of the positive charge. With that information, we know that Li+ has a higher polarizing power than Ca2+ which has a higher polarizing power than Cs+ and Ba2+...
- Sun Dec 09, 2018 12:33 am
- Forum: Biological Examples
- Topic: Examples To Know
- Replies: 1
- Views: 358
Re: Examples To Know
I believe that's the extent of what he went over in class.
- Sun Dec 09, 2018 12:32 am
- Forum: Quantum Numbers and The H-Atom
- Topic: quantum number, spin
- Replies: 3
- Views: 736
Re: quantum number, spin
There are only two options for ms or spin, usually denoted as +1/2 or -1/2. Electrons that are in the same orbital must have opposite spins.
- Sat Dec 08, 2018 10:00 pm
- Forum: DeBroglie Equation
- Topic: exhibiting wave-like properties
- Replies: 4
- Views: 615
exhibiting wave-like properties
Could someone remind me of the minimum wavelength at which a particle is said to exhibit wave-like properties?
- Sun Dec 02, 2018 8:19 pm
- Forum: Hybridization
- Topic: S Hybridization?
- Replies: 5
- Views: 476
Re: S Hybridization?
It's usually for atoms that are not central, like hydrogen.
- Sun Dec 02, 2018 8:15 pm
- Forum: Hybridization
- Topic: Double and Triple Bonds
- Replies: 17
- Views: 4254
Re: Double and Triple Bonds
They just add un-hybridized orbitals. The hybrid orbital stays the same but the extra electrons are held in p orbitals.
- Sun Dec 02, 2018 8:10 pm
- Forum: Lewis Acids & Bases
- Topic: 6th editions Fundamentals J #1
- Replies: 3
- Views: 374
Re: 6th editions Fundamentals J #1
I think it is because, in water, the H atoms in H2SO3 are likely to be attracted to the oxygen and form H3O whereas Ca(OH)2 dissociates into Ca and OH ions
- Sun Nov 18, 2018 1:26 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw Bond Angles
- Replies: 3
- Views: 193
Re: Seesaw Bond Angles
Ok thanks. From my discussion, I was under the impression that the trigonal planar pairs were affected, but not the linear ones. And also, often, in the textbook, it just says 90 and 120 in the solutions manual for seesaw structures rather than slightly less than 90 and 120. Do you know if it would ...
- Sun Nov 18, 2018 1:17 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Octahedral
- Replies: 2
- Views: 360
Re: Octahedral
They are named by the shape they form. If you were to connect the dots between four areas of electron density in our model, it would form a 3d shape with 4 triangular faces or planes so we call it tetrahedral. If you do this with the arrangement of 6 areas of electron density, it forms a 3d shape wi...
- Sun Nov 18, 2018 1:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw Bond Angles
- Replies: 3
- Views: 193
Seesaw Bond Angles
I'm a little confused about how the lone pair affects the bond angles in the seesaw geometry. Why does the lone pair not affect the 90 and 180 bond angles?
- Sun Nov 11, 2018 7:06 pm
- Forum: Lewis Structures
- Topic: Ionic compound
- Replies: 4
- Views: 498
Re: Ionic compound
Yes, I believe you draw the valence electrons around the atom that takes them and note the charges with brackets, but no lines because those indicate electron pairs that are shared covalently.
- Sun Nov 11, 2018 7:03 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: Importance of Dissociation Energy
- Replies: 1
- Views: 299
Re: Importance of Dissociation Energy
Dissociation energy is the amount of energy required to break a bond, so the stronger the bond. It's just important to know that the bond between ions is stronger than the bond between dipoles so that you know how certain molecules are likely to interact once you know which forces are acting on them.
- Sun Nov 11, 2018 6:52 pm
- Forum: Resonance Structures
- Topic: Hybrid Resonance
- Replies: 4
- Views: 646
Re: Hybrid Resonance
I believe it just refers to the actual structure of the molecule which would be a hybrid of all of the resonance structures
- Wed Oct 31, 2018 10:50 pm
- Forum: Lewis Structures
- Topic: The Number of Valence Electrons in Transition Metals
- Replies: 2
- Views: 392
Re: The Number of Valence Electrons in Transition Metals
You need to write out the electron configuration of the element and then count the electrons in levels past the last noble gas, so for Mn, it would be the number of additional electrons it has after [Ar].
- Wed Oct 31, 2018 12:02 am
- Forum: Ionic & Covalent Bonds
- Topic: Predicting which orbital an electron should be removed from to create 1+ ion
- Replies: 2
- Views: 285
Re: Predicting which orbital an electron should be removed from to create 1+ ion
Copper has a full 3d orbital. Cu: [Ar]3d^104s^1 The way Gail explained it today is that, although 4s is at a higher energy level, there is an additional energy cost to disrupting that full orbital, and since the difference between energy levels get smaller and smaller, it ends up requiring less ener...
- Tue Oct 30, 2018 11:49 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ground states (homework problem 2A.11)
- Replies: 2
- Views: 216
Re: Ground states (homework problem 2A.11)
The problem is telling you that when 3 electrons are removed from some metal (giving it a +3 charge), its electron configuration is [Ar]3d^6. Using the atomic number of Ar and the information that there are 6 additional electrons, you know that this mystery ion has 24 electrons. So you know that the...
- Tue Oct 30, 2018 11:38 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2B.1 Part B
- Replies: 2
- Views: 168
Re: 2B.1 Part B
I believe it is because carbon has the lowest ionization energy, and the atom with the lowest ionization energy is generally the central atom because it shares its electrons more readily.
- Sun Oct 28, 2018 5:43 pm
- Forum: Properties of Electrons
- Topic: Coulomb
- Replies: 4
- Views: 672
Re: Coulomb
I believe it is just the force of attraction between oppositely charged particles; particles of opposite charges are attracted to each other, while particles with the same charge repel each other.
- Sun Oct 28, 2018 5:20 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Affinity
- Replies: 1
- Views: 328
Re: Electron Affinity
You need to take into account the trends of electron affinity based on the periodic table. So, electron affinity decreases as you go down a group, because electrons are farther away from the nucleus and there is increased shielding because electrons are at higher energy levels. It increases as you g...
- Sat Oct 27, 2018 3:58 pm
- Forum: Lewis Structures
- Topic: When electrons do no pair in orbitals:
- Replies: 2
- Views: 135
Re: When electrons do no pair in orbitals:
So, I think you're talking about Hund's rule: that every orbital in a subshell must have one electron before any of them can have a pair. This is because is creates the lowest possible energy. Electrons repel each other so if they are in the same orbital, that repulsion creates a higher energy state.
- Sun Oct 21, 2018 7:31 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Exam 2
- Replies: 4
- Views: 373
Re: Exam 2
I believe Dr. Lavelle said that we will always have a full sheet of equations like on the first exam.
- Sun Oct 21, 2018 7:24 pm
- Forum: *Shrodinger Equation
- Topic: Wavelike Properties
- Replies: 1
- Views: 298
Re: Wavelike Properties
The double-slit experiment showed that electrons form wave-like interference patterns that curve around a barrier rather than going straight through the slit like a particle
- Sun Oct 21, 2018 7:22 pm
- Forum: Photoelectric Effect
- Topic: Kinetic Energy
- Replies: 3
- Views: 322
Re: Kinetic Energy
Yes, due if there is excess energy in removing the electron, it is conserved as kinetic energy of the electron. And the work function is the same as the amount of energy required to remove the electron
- Sun Oct 21, 2018 7:15 pm
- Forum: Photoelectric Effect
- Topic: Conditions that allow electron to be ejected from metal surface
- Replies: 12
- Views: 2183
Re: Come nditions that allow electron to be ejected from metal surface
Yes. Both are true. Just bear in mind that if the energy of the photon is higher than the energy required to remove the electron, the remaining energy will present as kinetic energy of the ejected electron; the energy is conserved.
- Sun Oct 14, 2018 3:38 pm
- Forum: Properties of Light
- Topic: Geiger and Marsden experiment
- Replies: 3
- Views: 208
Re: Geiger and Marsden experiment
So, the positively charged alpha particles were only deflected if the got close to the nucleus?
- Sun Oct 14, 2018 3:23 pm
- Forum: Properties of Light
- Topic: Colors and Frequency
- Replies: 14
- Views: 1606
Re: Colors and Frequency
It would help to have a general sense of how wavelength corresponds to the type of EM radiation, just because it would be easier to understand the real world implications of the practice problems. It would help you to know whether we're dealing with visible light or x-rays etc., but I'm not sure if ...
- Sun Oct 14, 2018 3:16 pm
- Forum: Properties of Light
- Topic: Wave vs. Particle Behavior
- Replies: 5
- Views: 488
Re: Wave vs. Particle Behavior
In a double slit experiment, it was shown that electrons formed an diffraction pattern like light waves, bending around the barriers, but electrons also have mass and can collide with and transfer energy to other particles.
- Thu Oct 04, 2018 10:19 pm
- Forum: Significant Figures
- Topic: Using Sig Figs Throughout a Problem?
- Replies: 6
- Views: 1142
Re: Using Sig Figs Throughout a Problem?
My TA said to treat it as if you did all of the intermediate calculations in one step. In other words, you only need to use sig figs in your final answer. I normally just use the numbers stored in my calculator throughout the problem and then write my answer with the correct number of sig figs.
- Thu Oct 04, 2018 9:59 pm
- Forum: Balancing Chemical Reactions
- Topic: L.5 Mass
- Replies: 3
- Views: 357
Re: L.5 Mass
You do need to convert to moles using the molar mass of each compound. You shouldn't need avogadro's number. Just convert the kg of NH4ClO4 to g and then to moles and you would need (5/3)x as many moles of Al so that the two reactants are proportional according to the molar ratios of the equation. T...
- Thu Oct 04, 2018 9:16 pm
- Forum: SI Units, Unit Conversions
- Topic: L35 Tons Conversion Rate
- Replies: 4
- Views: 429
Re: L35 Tons Conversion Rate
I believe you do have to convert to grams, because you will need to use molar ratios and molar masses are measured to g/mol^-1. I found that there are 907185 g in one US ton.
- Thu Oct 04, 2018 8:29 pm
- Forum: Significant Figures
- Topic: Limiting Reactants
- Replies: 6
- Views: 602
Re: Limiting Reactants
To find the limiting reactant, you need to compare the moles of each reactant, not the masses. To start, make sure you have balanced equation to represent the reaction. This will tell you the molar ratio in which the compounds react with each other. For example, if you have 4NH_{3}+5O_{2}\rightarrow...