Search found 65 matches
- Sun Mar 01, 2020 11:46 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Kelvin or Celsius?
- Replies: 86
- Views: 5197
Re: Kelvin or Celsius?
Use Kelvin, as the gas constant R includes it.
- Sun Mar 01, 2020 11:44 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrolytes vs electrodes
- Replies: 5
- Views: 304
Re: Electrolytes vs electrodes
Electrodes connect cells, while electrolytes are ions.
- Sun Mar 01, 2020 11:43 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Enzyme
- Replies: 4
- Views: 1204
Re: Enzyme
An enzyme is a biological catalyst that allows for reactions to proceed faster.
- Sun Mar 01, 2020 11:42 pm
- Forum: General Rate Laws
- Topic: Preferred way to write reaction rate
- Replies: 5
- Views: 377
Re: Preferred way to write reaction rate
The way it is written does not matter, it just makes it more easily understandable.
- Sun Mar 01, 2020 11:40 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Kinetics in Test 2?
- Replies: 13
- Views: 786
Re: Kinetics in Test 2?
Kinetics is not included in Test 2, only up to Electrochemistry.
- Sun Feb 23, 2020 11:39 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2 Topics
- Replies: 7
- Views: 487
Re: Test 2 Topics
Test 2 covers the last bit of Thermodynamics that wasn't on the midterm, as well as electrochemistry
- Sun Feb 23, 2020 11:38 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: STP
- Replies: 13
- Views: 706
Re: STP
273 K and 1atm under STP. It should be provided during tests.
- Sun Feb 23, 2020 11:37 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: G(not) and G
- Replies: 15
- Views: 701
Re: G(not) and G
G(not) represents standard Gibbs Free energy.
- Sun Feb 23, 2020 11:36 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Test 2
- Replies: 13
- Views: 636
Re: Test 2
The test should cover the end of thermo, as well as electrochemistry.
- Sun Feb 23, 2020 11:35 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2
- Replies: 9
- Views: 510
Re: Test 2
The test will be week 9 in discussion
- Sun Feb 09, 2020 11:31 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: X is to small
- Replies: 8
- Views: 471
Re: X is to small
X is dropped when it is less than 10^-3 and the percent at the end is less than 5
- Sun Feb 09, 2020 11:30 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE BOX
- Replies: 27
- Views: 759
Re: ICE BOX
If X is less than 10^-3
- Sun Feb 09, 2020 11:25 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Partial Pressure
- Replies: 7
- Views: 398
Re: Partial Pressure
Partial pressure is based upon the pressures of the gases in a reaction.
- Sun Feb 09, 2020 11:13 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Le Chatelier's Principle
- Replies: 5
- Views: 278
Re: Le Chatelier's Principle
Increasing pressure and decreasing volume increases concentration on the side with a greater amount of moles.
- Sun Feb 09, 2020 11:10 pm
- Forum: Ideal Gases
- Topic: Gas constant
- Replies: 10
- Views: 509
Re: Gas constant
The value used is dependent on the units given.
- Sun Feb 02, 2020 11:50 pm
- Forum: Phase Changes & Related Calculations
- Topic: Calorimeters
- Replies: 8
- Views: 432
Re: Calorimeters
Bomb calorimeters are isolated systems.
- Sun Feb 02, 2020 11:39 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Delta q and delta h
- Replies: 5
- Views: 273
Re: Delta q and delta h
Q is heat transfer, while H is enthalpy.
- Sun Feb 02, 2020 11:36 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: H2O as a Gas
- Replies: 69
- Views: 6150
Re: H2O as a Gas
Yes, include H2O as a gas, but not liquid.
- Sun Feb 02, 2020 11:32 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Temperature
- Replies: 14
- Views: 522
Re: Temperature
Negative delta H shows a release of energy, being exothermic
- Sun Feb 02, 2020 11:16 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Changing the energy of a system
- Replies: 9
- Views: 320
Re: Changing the energy of a system
You can change heat, mass, or do work on the system.
- Sun Jan 26, 2020 10:35 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Changing K
- Replies: 13
- Views: 472
Re: Changing K
K is changed by change in temperature.
- Sun Jan 26, 2020 10:34 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Gas Constant
- Replies: 13
- Views: 521
Re: Gas Constant
The gas constant needed will be based on the units of pressure. The constants should be on the formula sheets during tests.
- Sun Jan 26, 2020 10:27 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: exothermic reactions
- Replies: 19
- Views: 1899
Re: exothermic reactions
Increasing heat in an exothermic reaction favors the reactants.
- Sun Jan 26, 2020 10:19 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: endothermic
- Replies: 8
- Views: 295
Re: endothermic
Increasing temperature in an endothermic reaction would favor the forward reaction.
- Sun Jan 26, 2020 10:17 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Exothermic reaction
- Replies: 18
- Views: 641
Re: Exothermic reaction
In an exothermic reaction, decreasing the temperature will favor the formation of products, while increasing temperature would favor formation of reactants.
- Sun Jan 12, 2020 11:32 pm
- Forum: Ideal Gases
- Topic: K and Units
- Replies: 7
- Views: 305
Re: K and Units
Due to K being a ratio, it does not have units.
- Sun Jan 12, 2020 11:27 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Homogenous Equilibrium
- Replies: 13
- Views: 356
Re: Homogenous Equilibrium
Is there a certain significance to homogeneous and heterogeneous equilibrium? Or do we just need to know what they are?
- Sun Jan 12, 2020 11:25 pm
- Forum: Ideal Gases
- Topic: Aqueous Solutions
- Replies: 4
- Views: 132
Re: Aqueous Solutions
It is correct that solids and liquids are omitted from equilibrium constant concentrations. Aqueous solutions are included in the calculations.
- Sun Jan 12, 2020 11:23 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Types of Equilibrium Constants
- Replies: 7
- Views: 246
Re: Types of Equilibrium Constants
When there are gases, use Kp to show partial pressure, and when there are aqueous solutions, use Kc to show molarity.
- Sun Jan 12, 2020 11:21 pm
- Forum: Ideal Gases
- Topic: Q vs. K
- Replies: 10
- Views: 296
Re: Q vs. K
Q and K are both calculated similarly, but Q can be calculated at any time during the reaction and can be compared with K to determine the direction in which the reaction is favored.
- Sun Dec 01, 2019 8:22 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Number
- Replies: 4
- Views: 291
Re: Coordination Number
The coordination number of a central atom on a molecule refers to the number of bonds on it.
- Sun Dec 01, 2019 8:19 pm
- Forum: Biological Examples
- Topic: Cisplatin
- Replies: 5
- Views: 294
Re: Cisplatin
I thought the only thing regarding the structure of cisplatin we needed to remember was what side the Cl atoms were on.
- Sun Dec 01, 2019 8:13 pm
- Forum: Hybridization
- Topic: Writing the hydrization
- Replies: 10
- Views: 696
Re: Writing the hydrization
Since we’re on the topic of writing hybridization, does it matter if we write d hybridization before s and p? Or can we out it after.
- Sun Dec 01, 2019 8:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sigma Bond
- Replies: 10
- Views: 578
Re: Sigma Bond
Sigma bonds exist in single, double, and triple bonds.
- Sun Dec 01, 2019 8:09 pm
- Forum: Lewis Acids & Bases
- Topic: Proton acceptor and proton donor?
- Replies: 33
- Views: 2040
Re: Proton acceptor and proton donor?
Acids give H+ ions (protons). Bases receive H+ ions.
- Sun Nov 24, 2019 10:48 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Transition Metals
- Replies: 7
- Views: 443
Re: Transition Metals
Yes, the transition metals in the d-block all can form coordination compounds.
- Sun Nov 24, 2019 10:39 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: How to draw dipoles
- Replies: 7
- Views: 388
Re: How to draw dipoles
You will have the arrow pointing to the more electronegative atom, as well as the slightly negative and positive symbols on the respective atoms.
- Sun Nov 24, 2019 10:30 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Drawing molecules
- Replies: 7
- Views: 460
Re: Drawing molecules
Organic molecules are covered in future Chem courses, being 14C and 14D.
- Sun Nov 24, 2019 10:22 pm
- Forum: Biological Examples
- Topic: Coordination Compounds
- Replies: 2
- Views: 200
Re: Coordination Compounds
I'm not too sure what exactly, so you may want to go over the examples we covered in lectures and ask your TA/Lavelle for more information.
- Sun Nov 24, 2019 9:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Hybridization
- Replies: 7
- Views: 414
Re: Hybridization
In addition to the s and p orbitals, the d orbitals can be used in hybridization as well.
- Sun Nov 03, 2019 8:15 pm
- Forum: Octet Exceptions
- Topic: Elements with Exceptions to Octet Rule
- Replies: 1
- Views: 106
Re: Elements with Exceptions to Octet Rule
Typically, atoms in the third period or further down are exceptions to the Octet Rule, as they can use the d-orbitals for extra valence electrons.
- Sun Nov 03, 2019 8:12 pm
- Forum: Lewis Structures
- Topic: Which element at center of the structure
- Replies: 6
- Views: 499
Re: Which element at center of the structure
The least electronegative atom is placed in the center of the electron structures, with the exception of Hydrogen, which will never be in the center.
- Sun Nov 03, 2019 8:10 pm
- Forum: Octet Exceptions
- Topic: Expanded Valence Shells
- Replies: 6
- Views: 171
Re: Expanded Valence Shells
Atoms within the third period or past that can have expanded valence shells for electrons, since they have the d-orbitals.
- Sun Nov 03, 2019 8:07 pm
- Forum: Electronegativity
- Topic: size
- Replies: 8
- Views: 452
Re: size
The atomic radius of an atom increases as you go down the periodic table and towards the left.
- Sun Nov 03, 2019 8:05 pm
- Forum: Bond Lengths & Energies
- Topic: Strength of Bonds
- Replies: 16
- Views: 623
Re: Strength of Bonds
The double and triple covalent bonds are stronger than the single bonds, as more electrons are shared. As a result, these bonds are shorter.
- Sun Oct 27, 2019 6:47 pm
- Forum: Resonance Structures
- Topic: Bond lenghts.
- Replies: 11
- Views: 384
Re: Bond lenghts.
If we were required to know bond lengths, I think the values would be given to us to use in whatever calculations are required.
- Sun Oct 27, 2019 6:43 pm
- Forum: Lewis Structures
- Topic: Clarification
- Replies: 6
- Views: 200
Re: Clarification
We are saying that there are exceptions to the octet rule, as formal charges of zero take priority, but these exceptions will still mean that the atom breaking the octet rule would have more than 8 atoms or no?
- Sun Oct 27, 2019 6:38 pm
- Forum: Octet Exceptions
- Topic: Exceeding the Octet Rule
- Replies: 5
- Views: 204
Re: Exceeding the Octet Rule
Central atoms in the 3rd period or further down are able to accommodate more than 8 electrons due to having the d-orbitals available, as d-orbitals start becoming available at n=3.
- Sun Oct 27, 2019 6:29 pm
- Forum: Resonance Structures
- Topic: Determining Resonance Structures
- Replies: 6
- Views: 261
Re: Determining Resonance Structures
I thought that resonance structures were "ideal" when the formal charges of the atoms were equal to 0? Or close to that value in some cases.
- Sun Oct 27, 2019 6:26 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Bonds
- Replies: 11
- Views: 524
Re: Covalent Bonds
Indeed, and covalent bonds are different than ionic bonds because electrons are shared between the non-metals.
- Sun Oct 20, 2019 11:46 pm
- Forum: Trends in The Periodic Table
- Topic: Electron affinity
- Replies: 5
- Views: 317
Re: Electron affinity
The trend for electron affinity and electronegativity is the same, but what are the differences between the two? Or rather, how similar or they?
- Sun Oct 20, 2019 11:45 pm
- Forum: Trends in The Periodic Table
- Topic: memorization
- Replies: 3
- Views: 271
Re: memorization
A quick tip for trends is that atomic radius increases as you go down and left, while ionization energy and electronegativity increase as you go up and to the right. In addition to these, I believe another trend is that elements as you go down and to the left on the periodic table tend to have more...
- Sun Oct 20, 2019 11:43 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions in Electron Configurations
- Replies: 5
- Views: 164
Exceptions in Electron Configurations
So in lecture, I remember there was a briefing discussion regarding the exceptions of the configurations of electrons in the groups with Chromium and Copper, taking one electron from the s orbitals to half fill their d-orbital. Is there a specific reason regarding the energy of these and why the def...
- Sun Oct 20, 2019 11:39 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration and orbital diagram
- Replies: 1
- Views: 77
Re: Electron Configuration and orbital diagram
Orbital diagrams are used to display the electrons within an atom. According to Hund's Rule, an each orbital in a subshell will have one electron in each at the ground state, and these unpaired electrons will generally be spinning up initially. When all the orbitals are filled, electrons will begin ...
- Sun Oct 20, 2019 11:32 pm
- Forum: Trends in The Periodic Table
- Topic: ionization energy
- Replies: 11
- Views: 990
Re: ionization energy
The first ionization energy of an electron is the energy required to remove the first electron from a ground state atom. The trend for this is seen on the periodic table as you go to the right and up.
- Sun Oct 13, 2019 11:11 pm
- Forum: Properties of Light
- Topic: Angstrom
- Replies: 10
- Views: 464
Re: Angstrom
I think that most questions, at least on the tests, would ask for a specific unit for the final answer to be in.
- Sun Oct 13, 2019 11:09 pm
- Forum: Significant Figures
- Topic: sig figs and periodic tables
- Replies: 11
- Views: 677
Re: sig figs and periodic tables
When I use the periodic table for math on problems, I take the entire number shown on it, then round off my final answer to the required number of sig figs, in hopes of retaining accuracy.
- Sun Oct 13, 2019 9:54 pm
- Forum: Properties of Light
- Topic: When to use the Planck's Constant?
- Replies: 6
- Views: 315
Re: When to use the Planck's Constant?
I believe that Planck's Constant (h) is also able to be used when determining the energy level of an electron.
En = -hR/n2
En = -hR/n2
- Sun Oct 13, 2019 9:44 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test 1 [ENDORSED]
- Replies: 107
- Views: 17564
Re: Test 1 [ENDORSED]
Can someone explain what Angstroms are? I was confused on the test on this question. Angstroms are a unit of length equivalent to 10^(-10) m. I was taken aback by this question on the test as I do not ever remember being told we had to memorize the quant. value of Angstroms. Did I miss that in clas...
- Sun Oct 13, 2019 9:43 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test 1 [ENDORSED]
- Replies: 107
- Views: 17564
Re: Test 1 [ENDORSED]
I don't think sig figs were looked at too carefully for this test.
Also, I believe questions heading in the direction are given partial credit, and the grader will read through your work.
Also, I believe questions heading in the direction are given partial credit, and the grader will read through your work.
- Sun Oct 06, 2019 10:37 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical Ratio Rounding
- Replies: 6
- Views: 684
Re: Empirical Ratio Rounding
As Ami mentioned, .9 would be okay to round up for figuring out empirical formulas, but what if it is .8?
- Sun Oct 06, 2019 10:05 pm
- Forum: SI Units, Unit Conversions
- Topic: Calculators Permitted on the Test
- Replies: 2
- Views: 82
Re: Calculators Permitted on the Test
I believe a CASIO scientific calculator is permitted, as it meets the criteria listed on the syllabus. I will personally be using a TI-36X scientific calculator which (hopefully) should work.
- Sun Oct 06, 2019 10:00 pm
- Forum: Significant Figures
- Topic: Reviewing Sig Figs
- Replies: 3
- Views: 146
Re: Reviewing Sig Figs
On the class website, there is a link that will lead you to a PDF for assistance regarding sig figs. It has examples included, so it doesn't contain strictly definitions.
- Sun Oct 06, 2019 9:58 pm
- Forum: Significant Figures
- Topic: Sig Figs
- Replies: 3
- Views: 91
Re: Sig Figs
In addition to resources already listed, the class website for 14A has something that will help with sig figs. It provides a link to a document covering how to use sig figs.
- Sun Oct 06, 2019 3:04 pm
- Forum: Significant Figures
- Topic: Sig Fig Test Importance
- Replies: 2
- Views: 147
Re: Sig Fig Test Importance
Based on what I've read on other posts on this regarding the usage of sig figs, I think sig figs are required for the first test. Even if they aren't required for the first test, I'm sure that learning them now in preparation for future tests won't hurt you.