Search found 60 matches
- Sun Mar 17, 2019 7:51 pm
- Forum: Balancing Redox Reactions
- Topic: Reduction powers
- Replies: 2
- Views: 503
Re: Reduction powers
Wouldn’t you determine that using oxidizing potential ?
- Sun Mar 17, 2019 7:45 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: bomb calorimeter
- Replies: 8
- Views: 1158
Re: bomb calorimeter
Yea w=0 in that case
- Sun Mar 17, 2019 7:32 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidizing powers
- Replies: 2
- Views: 485
Re: Oxidizing powers
An element with a high reduction potential is a powerful oxidizing agent.
- Sun Mar 17, 2019 7:28 pm
- Forum: Biological Examples
- Topic: ATP example
- Replies: 7
- Views: 3045
Re: ATP example
Wouldn’t the reaction be exergonic since it’s giving off energy and not requiring it?
- Sun Mar 17, 2019 7:25 pm
- Forum: General Science Questions
- Topic: sig figs
- Replies: 4
- Views: 778
Re: sig figs
In that case I would do 2 to account for the decimal and what not
- Sun Mar 17, 2019 1:51 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Midterm Q3-C
- Replies: 4
- Views: 653
Re: Midterm Q3-C
Thank you so much!
- Sun Mar 17, 2019 1:38 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Heat Capacity Intensive or Extensive?
- Replies: 4
- Views: 639
Re: Heat Capacity Intensive or Extensive?
I don't know about your reasoning, but heat capacity is extensive. It changes when it becomes specific heat capacity, as that is intensive instead.
- Sun Mar 17, 2019 1:16 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 6N.1
- Replies: 1
- Views: 485
Re: 6N.1
Look at the order of the elements in the actual equation that is given to you. The half reactions displayed are backwards in a sense, which is how you can get the cell potential value. Mn is oxidized to become Mn2+ and Ti2+ is reduced to become Ti.
- Sun Mar 17, 2019 1:11 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Midterm Q3-C
- Replies: 4
- Views: 653
Midterm Q3-C
Can someone please explain the reasoning behind the answer for Q3C on the midterm please, Im thinking way too hard.
- Sun Mar 17, 2019 12:41 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: chemical to electrical
- Replies: 2
- Views: 538
Re: chemical to electrical
A galvanic cell
- Sun Mar 17, 2019 12:39 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: salt bridge
- Replies: 4
- Views: 693
Re: salt bridge
A salt bridge is used to neutralize the two solutions in order to prevent them from becoming too negative or too positive. This way, a current can still be transferred across the wire.
- Sun Mar 17, 2019 12:20 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: galvanic/voltaic cells
- Replies: 7
- Views: 804
Re: galvanic/voltaic cells
They are the same thing
- Sun Mar 17, 2019 12:18 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Liquids and Solids
- Replies: 2
- Views: 448
Re: Liquids and Solids
p\Pure liquids and pure solids have activities that are one (they don't appear in the mass action expression). Thus if you add more of them they will not affect the equilibrium at all. Solubility is a situation like this. If you have a saturated solution and you add more solid nothing happens (the r...
- Sun Mar 17, 2019 12:10 am
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: higher entropies
- Replies: 6
- Views: 777
Re: higher entropies
Higher entropy means an increase in disorder.
- Sun Mar 17, 2019 12:07 am
- Forum: *Enzyme Kinetics
- Topic: catalyst
- Replies: 23
- Views: 2435
Re: catalyst
Enzymes are proteins functioning as catalysts that speed up reactions by lowering the activation energy. A simple and succinct definition of an enzyme is that it is a biological catalyst that accelerates a chemical reaction without altering its equilibrium.
- Sun Mar 17, 2019 12:03 am
- Forum: Experimental Details
- Topic: picking a trial
- Replies: 13
- Views: 1534
Re: picking a trial
It doesnt really matter but you can make calculations a little bit easier by choosing trials with simpler numbers.
- Sun Mar 17, 2019 12:02 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: galvanic cells
- Replies: 6
- Views: 962
Re: galvanic cells
Pretty sure porous disk is just a single line and the salt bridge is a double line.
- Sat Mar 16, 2019 11:57 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6N1 b) 7th edition
- Replies: 1
- Views: 390
Re: 6N1 b) 7th edition
It could be an error in the solutions? I did the problem and its definitely 1e.
- Sat Mar 16, 2019 11:47 pm
- Forum: Balancing Redox Reactions
- Topic: 6L 3D (7th Edition)
- Replies: 1
- Views: 449
Re: 6L 3D (7th Edition)
The easy way is to just remember that the right side of the electrode is the site of reduction and the left side is the site of oxidation. Is this what you were referring to?
- Sat Mar 16, 2019 11:09 pm
- Forum: First Order Reactions
- Topic: Graphs/Plots
- Replies: 2
- Views: 537
Re: Graphs/Plots
I dont think so to be honest, those are the main portions that tell you anything about the reaction.
- Sat Mar 16, 2019 10:53 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation Numbers
- Replies: 1
- Views: 476
Re: Oxidation Numbers
It is helpful to memorize the oxidation numbers for common elements like for oxygen and hydrogen. So for example, in MnO4 minus; oxygen's oxidation number is -2. There are 4 oxygens which totals up to a -8. A +8 would be needed to balance out the compound but since the compound is -1, Mn's oxidation...
- Sat Mar 16, 2019 10:48 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: adiabatic systems
- Replies: 10
- Views: 919
Re: adiabatic systems
It means that there it no additional heat being transferred between or within the system. There could already be heat in there to begin with but it will not change.
- Sat Mar 16, 2019 10:35 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: equilibirum expression
- Replies: 3
- Views: 625
Re: equilibirum expression
You don't include solids or liquids I think. Just aqueous and gases.
- Sun Mar 10, 2019 11:40 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L.3
- Replies: 1
- Views: 215
Re: 6L.3
The second set you listed are the actual half reactions.
- Sun Mar 10, 2019 11:14 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Units of k
- Replies: 7
- Views: 997
Re: Units of k
I was having trouble explaining out the equation and what makes the units different but I found a great explanation online that outlines it nicely. The rate of a chemical reaction r (or c t^-1) is given by: r = k [A]^a x [B]^b where k is the rate constant, A and B are the concentrations of the two r...
- Sun Mar 10, 2019 11:08 pm
- Forum: Second Order Reactions
- Topic: Zero, First, Second Reactions
- Replies: 2
- Views: 397
Re: Zero, First, Second Reactions
The zero order reaction means that the rate of the reaction does not depend upon the concentration of the reactant. When the rate of the reaction depends on the first power of the reactant concentration in the rate equation, then the reaction is said to follow first order. When the rate of the react...
- Sun Mar 03, 2019 11:59 pm
- Forum: Zero Order Reactions
- Topic: Order distinction
- Replies: 9
- Views: 1022
Re: Order distinction
The rate equation can help you determine the order of the reaction. It shows the increase or decrease of a particular substance with respect to time. Or you can just add together the total order numbers of each reactant.
- Sun Mar 03, 2019 11:51 pm
- Forum: General Rate Laws
- Topic: Edition 6 15.37
- Replies: 1
- Views: 193
Re: Edition 6 15.37
To start, for a first order reaction:
T_1/2= (0.693/K), so all you really have to do is substitute in for K.
T_1/2= (0.693/K), so all you really have to do is substitute in for K.
- Sun Mar 03, 2019 11:42 pm
- Forum: General Rate Laws
- Topic: Average rate of products and reactants
- Replies: 1
- Views: 191
Re: Average rate of products and reactants
I believe so, unless you came onto a reaction where product was being formed and the reactant concentration was not changing, which I dont believe could happen.
- Sun Mar 03, 2019 11:36 pm
- Forum: General Rate Laws
- Topic: rate laws
- Replies: 1
- Views: 237
Re: rate laws
I mean catalysts definitely affect the rate by changing the reaction mechanism when, in case, it is actually present. So I believe it is included when it is present and not included when it is not. But from further reading I've seen that it is included in the rate constant when the constant is actua...
- Fri Feb 01, 2019 4:10 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Enthalpy
- Replies: 3
- Views: 391
Re: Enthalpy
At constant pressure, the heat of reaction is equal to the enthalpy change of the system. Most chemical reactions occur at constant pressure, so enthalpy is more often used to measure heats of reaction than internal energy.
- Fri Feb 01, 2019 3:52 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Final Temperature at Constant Pressure, and then at Constant Volume
- Replies: 2
- Views: 1546
Final Temperature at Constant Pressure, and then at Constant Volume
Hey guys, I am working on problem 4C.3, which asks to calculate the final temperature and the change in enthalpy when 765 J of energy is transferred as heat to 0.820 mol Kr (g) at 298 L and 1.00 atm. I know how to calculate the final temperature and enthalpy with this information but I am unsure of ...
- Tue Jun 12, 2018 4:27 pm
- Forum: Conjugate Acids & Bases
- Topic: Acids and Bases
- Replies: 2
- Views: 397
Re: Acids and Bases
Yes you can split (dissociate) weak acids and bases; however, since they are weak they just wont dissociate completely like strong acids or bases do. They will partially dissociate.
- Sun Jun 03, 2018 10:57 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Radical
- Replies: 4
- Views: 429
Re: Radical
I think since there is an unpaired electron, the half-filled lone-pair orbital would demand less space. So if it demands less space than a full one then the bond angle would open up slightly. Someone correct me if I am off please haha. An example of this would be NO2
- Sun Jun 03, 2018 10:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Confusion about lone pair placement
- Replies: 2
- Views: 369
Re: Confusion about lone pair placement
Are you talking about when trying to determine shape? If so I believe it usually appears on the central atom. At least that is what I have seen in most examples. So like if you are drawing VSEPR for SF(4), there would be two 90 degree lone pair bonding pair repulsions pushing the other fluorines awa...
- Sun Jun 03, 2018 10:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Pi/Sigma bonds clarification
- Replies: 4
- Views: 405
Re: Pi/Sigma bonds clarification
The sigma bond is more just like your basic head on covalent bond, where the bond is in line with the bonding orbitals. The pi bond is a covalent bond perpendicular to the bond direction, which is usually in p-orbitals never s. This is why you wouldn't be able to rotate a double or triple bond aroun...
- Sun May 27, 2018 9:53 pm
- Forum: Resonance Structures
- Topic: Contributing to Resonance Structures
- Replies: 4
- Views: 595
Contributing to Resonance Structures
What more makes a molecule contribute to a resonance structure other than just moving around the double or triple bonds in different place, because that is usually what I resort to. Is there more of a method to this? I've never quite fully understood.
- Sun May 27, 2018 9:45 pm
- Forum: Lewis Structures
- Topic: bonds
- Replies: 2
- Views: 268
Re: bonds
To answer your first question, there's a lot of math involved for the technical answer but if the dissociation energy is higher then the bond is shorter, and vice versa. For the second question, they want to be as far apart from each other because the regions with negative electrical charge will rep...
- Sun May 27, 2018 9:36 pm
- Forum: Resonance Structures
- Topic: Radicals
- Replies: 3
- Views: 478
Re: Radicals
A radical is when you count the number of valence electrons and there is an odd number, resulting in an unpaired electron. They are important because they influence the reactivity of a molecule.
- Sun May 27, 2018 9:30 pm
- Forum: Ionic & Covalent Bonds
- Topic: Partial charge or full charge
- Replies: 4
- Views: 5570
Re: Partial charge or full charge
Its easier to spot a partial charge in a covalent too when the electronegativities between the two atoms are more different. When they are about the same or closer to being the same then the electrons are more equally shared and it can be less noticeable per say.
- Sun May 13, 2018 9:38 pm
- Forum: Lewis Structures
- Topic: Octet rule
- Replies: 1
- Views: 399
Re: Octet rule
Here are common violations to the octet rule: 1. There are a few stable compounds that have an odd number of electrons in their valence shell, which forces at least one atom in the compound to violate the octet rule. An example is NO, where the N has 7 valence electrons and O has a full 8. 2. There ...
- Sun May 13, 2018 9:20 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma Bonds
- Replies: 5
- Views: 640
Sigma Bonds
I was looking up stuff about sigma and pi bonds because I couldn't be in class on Friday and this site said, "Note that sigma bond has been referred to as the strongest type of covalent bond because the extent of overlap is maximum in case of orbitals involved in the formation of the sigma bond...
- Sun May 13, 2018 9:01 pm
- Forum: Lewis Structures
- Topic: Meaning of chemical bond
- Replies: 5
- Views: 606
Re: Meaning of chemical bond
Well, it depends on what bond you are referring to. In a covalent bond, the electrons are shared between the atoms. If the bond is an ionic, then an atom basically takes or borrows (whichever way you see it) an electron or multiple from another atom.
- Sun May 06, 2018 8:01 pm
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity
- Replies: 3
- Views: 448
Re: Electron Affinity
An easy way to think about electron affinity is the amount of energy required to [censored] an electron from a specific atom. This can also be thought of as how strong an atom's pull on its electrons are. If an atom has a high electron affinity, it would not be easy to pull off one of its electrons.
- Sun May 06, 2018 6:44 pm
- Forum: Trends in The Periodic Table
- Topic: electronegativity
- Replies: 4
- Views: 543
Re: electronegativity
Electronegativity describes an atom's tendency to attract bonding pair electrons to itself, which can be determined mainly by the number of valence electrons in the outer shell. In theory, an atom wants 8 outer valence electrons to feel completely stable... so to satisfy that it will pull from other...
- Sun May 06, 2018 5:58 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: electron configuration of chromium? [ENDORSED]
- Replies: 3
- Views: 596
Re: electron configuration of chromium? [ENDORSED]
The way I know Cr's electron configuration to be is: [Ar] 3d^5 4s^1... this is still different from the regular way we would find electron configuration for it, which is [Ar] 3d^4 4s^2 and it is one of the exceptions. In order for Cr to be more stable it would rather have its d and s energy level be...
- Sun Apr 29, 2018 11:54 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Short hand for test
- Replies: 2
- Views: 291
Re: Short hand for test
I asked a question like that in class and Lavelle made it clear that shorthand could be used and it is indeed the closest noble gas. Im sure if he wanted the longer more detailed version he would specifically say on the test.
- Sun Apr 29, 2018 11:50 pm
- Forum: Trends in The Periodic Table
- Topic: atomic radius
- Replies: 4
- Views: 495
Re: atomic radius
Im not quite sure if we will be asked to calculate the atomic radius ever but I think its worth knowing how to get a generalization with a periodic trend. In general, the size of an atom will decrease when you go from left to right on the periodic table but will increase as you go down a certain gro...
- Sun Apr 29, 2018 11:44 pm
- Forum: Trends in The Periodic Table
- Topic: ionization energy
- Replies: 3
- Views: 325
Re: ionization energy
Atomic number, which correlates with atomic mass increases from left to right, top to bottom. Ionization energy increases from left to right, bottom to top. Hope this helps.
- Sun Apr 29, 2018 11:44 pm
- Forum: Trends in The Periodic Table
- Topic: ionization energy
- Replies: 3
- Views: 325
Re: ionization energy
Atomic number, which correlates with atomic mass increases from left to right, top to bottom. Ionization energy increases from left to right, bottom to top. Hope this helps.
- Sun Apr 29, 2018 11:33 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Pd electron configuration
- Replies: 2
- Views: 765
Re: Pd electron configuration
I looked up why that would be the case I sometimes dont understand how that d level works the way it does. What I found out was that full d orbitals are more stable than partially filled ones and that at higher energy levels are said to be degenerated. That means that the energy levels I guess are c...
- Sun Apr 29, 2018 11:27 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron's Spin
- Replies: 3
- Views: 263
Re: Electron's Spin
So, the way it was discovered was shooting a beam of the e- through a passageway of two magnets, one north pole and one south pole. When the electrons went through they would either pull upwards or pull downwards, indicating that there was a type of spinning involved; Hopefully that answers your que...
- Sun Apr 22, 2018 11:56 pm
- Forum: Properties of Electrons
- Topic: Heisenburg Indeterminancy Equation
- Replies: 1
- Views: 297
Re: Heisenburg Indeterminancy Equation
I just now realized this is in the wrong forum but the question still stands haha.
- Sun Apr 22, 2018 11:53 pm
- Forum: Properties of Electrons
- Topic: Heisenburg Indeterminancy Equation
- Replies: 1
- Views: 297
Heisenburg Indeterminancy Equation
In class I was having trouble understanding the image Lavelle drew on the board to explain what the Heisenberg indeterminacy equation determines, can someone explain how the model worked because I am still lost on it. Also is the indeterminacy equation only good for showing the uncertainty of a spec...
- Sun Apr 22, 2018 11:37 pm
- Forum: Properties of Light
- Topic: Test 2 Material
- Replies: 12
- Views: 1110
Re: Test 2 Material
I believe it is new material... Lavelle sent out an email with the specific questions that Test 2 will cover.
- Sun Apr 22, 2018 11:35 pm
- Forum: Properties of Light
- Topic: Amplitude and Intensity
- Replies: 6
- Views: 666
Re: Amplitude and Intensity
Light and intensity are not the same, although light can have varying intensities. Light consists of photons while intensity is simply a measurement. When measuring the intensity of light, it is specifically the amount of photons being emitted per unit of time. To use it in a situation is that even ...
- Sun Apr 15, 2018 11:59 pm
- Forum: Properties of Light
- Topic: plancks constant
- Replies: 2
- Views: 151
Re: plancks constant
It relates the energy of one photon of electromagnetic radiation to the frequency of that radiation.
- Sun Apr 15, 2018 11:58 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg formula
- Replies: 1
- Views: 231
Re: Rydberg formula
The Rydberg formula is used to predict the wavelength of light from when an electron is moving in between different energy levels of an atom. This is the formula: 1/λ = RZ2(1/n12 - 1/n22). Youll have to look up what the formula looks like because I cant paste it to look correctly haha.
- Sun Apr 15, 2018 11:54 pm
- Forum: Properties of Light
- Topic: Wave particle duality
- Replies: 3
- Views: 191
Re: Wave particle duality
From all the sources that I looked up, because I thought your question was interesting, I think constructive and destructive interference only happens between two waves because you only add or subtract the amplitudes of two waves. I never saw anyone talk about how to do that with more than two waves...
- Sun Apr 15, 2018 11:41 pm
- Forum: Properties of Light
- Topic: Amplitude
- Replies: 3
- Views: 137
Re: Amplitude
What do you mean by "will cause in an increase in effect"?