Search found 62 matches
- Sun Mar 17, 2019 5:38 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: tripotic acid
- Replies: 2
- Views: 1475
Re: tripotic acid
A triprotic acid is an acid that has three acidic protons. phosphoric acid is an example of triprotic acid.
- Fri Mar 15, 2019 9:04 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: K' VS K
- Replies: 1
- Views: 256
K' VS K
In problems like 15.61 and 15.63, K values are given at different temperature but they are not specified to be k' or k. How does one decide which is which?
- Thu Mar 14, 2019 4:42 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: 15.39 6th edition
- Replies: 1
- Views: 562
15.39 6th edition
in this question part b calls for the time required for the concentration of B to increase to 0.19 M, given that k=.0035 1/Mmin in the rate law for the loss .The solution manual has the answer .055(molA)/L= .37[A]0. Can someone explain how they got .37
- Sun Mar 10, 2019 3:50 pm
- Forum: Zero Order Reactions
- Topic: Zero Order Reactions
- Replies: 1
- Views: 245
Re: Zero Order Reactions
Zero-order reactions usually imply a catalysts since the rate is only defined by k, not on how much the concentration of the reactants are increased.
- Sun Mar 10, 2019 1:17 pm
- Forum: General Science Questions
- Topic: Free Expansion
- Replies: 3
- Views: 596
Re: Free Expansion
Free expansion can be seen when trying open a tight jar. If you run the jar under hot water, the increase of heat will cause the gas inside to expand and push pressure onto the lid slightly. This will cause the lid to loosen and open easily.
- Sun Mar 10, 2019 1:07 pm
- Forum: General Rate Laws
- Topic: how to determine the rate law
- Replies: 2
- Views: 247
Re: how to determine the rate law
The rate constant increases for an increase in temperature
- Tue Mar 05, 2019 10:00 pm
- Forum: First Order Reactions
- Topic: Units
- Replies: 1
- Views: 200
Units
If the unit for first order reaction is 1/s, then why does the first order reaction of question 15.11 have the units mols/Ls?
- Sat Mar 02, 2019 12:44 pm
- Forum: General Rate Laws
- Topic: rate law
- Replies: 3
- Views: 377
Re: rate law
The rate law tells us the rate at which the reaction occurs, and the equilibrium toward which it proceeds. It is derived from the concentrations or partial pressures of the reactants.
- Thu Feb 28, 2019 7:37 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 4.37 c
- Replies: 1
- Views: 218
Re: 4.37 c
Since H2 is a gas the pressure is listen instead of its concentration, similar to partial pressure expression.
- Thu Feb 28, 2019 7:32 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Cell Potential Spontaneity
- Replies: 7
- Views: 870
Re: Cell Potential Spontaneity
When the cell potential is positive the reaction is favorable to occur and therefore spontaneous. This can be related to the equation of Delta G = -nfe n cannot be negative and F is positive therefore a positive cell potential will result in a -delta G making the reaction spontaneous.
- Sun Feb 24, 2019 3:32 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Redox
- Replies: 4
- Views: 490
Re: Balancing Redox
Yes this is an intensive property because it has a set voltage regardless of the electrons passing through it.
- Sun Feb 24, 2019 3:29 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: cell potential vs emf
- Replies: 2
- Views: 267
Re: cell potential vs emf
The electromotive force or emf is the energy provided by a cell or a battery per coulomb of charge passing through it, and it is measured in volts. The cell potential is the measurement of how much voltage exists between two half cells of a battery. While the emf is the potential difference between ...
- Sun Feb 24, 2019 12:31 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Calculations for Gibbs free energy
- Replies: 2
- Views: 368
Re: Calculations for Gibbs free energy
When given the number of moles and asked to find delta G, you can use the moles when finding entropy by subtracting the number of moles of reactants from the products.
- Sat Feb 16, 2019 3:00 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Midterm Ice Table
- Replies: 6
- Views: 701
Re: Midterm Ice Table
I think there was two questions that required an ice table for the midterm. Only the question that specified no approximations could be made required the use of the quadratic formula. The other one however could be approximated.
- Sat Feb 16, 2019 2:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Gibbs Energy Study Guide
- Replies: 1
- Views: 334
Re: Gibbs Energy Study Guide
Thank you so much!!
- Wed Feb 13, 2019 1:12 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Homework
- Replies: 1
- Views: 245
Homework
Is there homework due this week in discussion?
- Sat Feb 09, 2019 4:02 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 3/2R and 5/2R
- Replies: 5
- Views: 684
Re: 3/2R and 5/2R
This is used in monoatomic ideal gases. At constant volume the heat capacity, Cv = 3/2R, and at Constant Pressure, Cp= 5/2 R
- Sat Feb 09, 2019 3:56 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: DeltaS=kBlnW
- Replies: 3
- Views: 644
Re: DeltaS=kBlnW
This equation is used when you are looking for the change in entropy of a molecule based on its degeneracy (W or the number of ways the atom can be arranged) at any temp. Kb is the boltzmann constant = 1.381 x 10^-23 J/K.
- Sat Feb 09, 2019 3:47 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta H
- Replies: 4
- Views: 429
Re: Delta H
Delta H equals q when there is no work done (this could happen when the volume does not change). this means that the enthalpy change equals the heat that is exchanged between the system and its surroundings
- Sun Feb 03, 2019 8:38 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: U vs. H
- Replies: 2
- Views: 769
Re: U vs. H
Delta H is the heat of reaction under constant pressure and Delta U is the heat under constant volume . Delta H is equal to Delta U, the change in internal energy (heat transfer), plus P, constant pressure, times the Delta V, the change in volume. They are only equal when Delta U is under typical co...
- Sun Feb 03, 2019 3:15 pm
- Forum: Calculating Work of Expansion
- Topic: internal vs. external pressure
- Replies: 3
- Views: 6009
Re: internal vs. external pressure
Yes, when a system is at equilibrium, the internal pressure is approximately equal to the external pressure.
- Sat Feb 02, 2019 3:03 pm
- Forum: Calculating Work of Expansion
- Topic: work done by vs on a system
- Replies: 5
- Views: 772
Re: work done by vs on a system
This is correct because If work is done by a system, the system is using energy, therefore losing its internal energy causing a negative w. If work is done ON a system, energy is being put into the system making w positive.
- Sat Jan 26, 2019 2:07 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: H and Q
- Replies: 4
- Views: 506
Re: H and Q
Enthalpy is the amount of heat, H, released or absorbed at a constant pressure, q.
- Wed Jan 23, 2019 10:35 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc and Kp
- Replies: 12
- Views: 1800
Re: Kc and Kp
if looking for Kp with concentration given, n/v, can be substituted for the concentration and the pressure can be isolated in order to find the partial pressure of that gas and compete the Kp expression.if looking for Kc with pressure given, p, can be inserted in the equation and n/v can be isolated...
- Wed Jan 23, 2019 10:26 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: correct x from quadratic equation 12.55 6th edition
- Replies: 1
- Views: 107
correct x from quadratic equation 12.55 6th edition
The quadratic equation leads me to two x's, one Is .14, and the other is .44. in the solution manual it says .44 is negative but I've repeated my calculations numerous times and cannot achieve a negative .44. How do I know which x to use to find the PH?
- Sat Jan 19, 2019 5:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: temperature
- Replies: 2
- Views: 199
Re: temperature
Temperature and pressure are directly proportional when the volume is constant, and Temperature and volume are directly proportional when pressure is constant.
- Sat Jan 19, 2019 5:28 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5I.13 (b) - 7th edition - sig figs
- Replies: 1
- Views: 71
Re: 5I.13 (b) - 7th edition - sig figs
8*10^-4 has one sig fig because you only count the sig figs in the number being multiplied. I believe Lavelle has stated that 2 decimal places for the answer is acceptable for these problems.
- Sat Jan 19, 2019 5:24 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K - small verses big
- Replies: 4
- Views: 424
Re: K - small verses big
if given the components of a reaction and a Kb/Ka, does a larger Ka mean the reaction entails the dissociation of an acid?
- Sat Jan 12, 2019 2:02 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Changes in Systems
- Replies: 3
- Views: 324
Re: Changes in Systems
If temperature changes the equilibrium constant, then can Q be compared to K?
- Sat Jan 12, 2019 1:50 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc and Kp
- Replies: 12
- Views: 1800
Re: Kc and Kp
If asked for the K expression, can Kc and Kp be used interchangeably?
- Sat Jan 12, 2019 1:48 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Table
- Replies: 6
- Views: 635
Re: ICE Table
Are ice tables always based on concentrations?
- Sun Dec 09, 2018 3:27 pm
- Forum: DeBroglie Equation
- Topic: Calculating Velocity
- Replies: 9
- Views: 1606
Re: Calculating Velocity
yes and you could also use ke=1/2mv^2
- Sun Dec 09, 2018 3:21 pm
- Forum: Hybridization
- Topic: Hybrid Orbitals
- Replies: 6
- Views: 712
Re: Hybrid Orbitals
most likely the answer will be just sp3
- Sun Dec 09, 2018 3:17 pm
- Forum: Naming
- Topic: Naming question with anion
- Replies: 2
- Views: 615
Re: Naming question with anion
If its a coordination compound it has to have -o -ido or -ato at the end of the name
- Mon Dec 03, 2018 12:15 am
- Forum: Ionic & Covalent Bonds
- Topic: Bond Lengths
- Replies: 5
- Views: 1296
Re: Bond Lengths
This depends on the electronegativity of the atoms creating the bond
- Mon Dec 03, 2018 12:04 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: identifying strong/weak acids and bases
- Replies: 1
- Views: 282
Re: identifying strong/weak acids and bases
The recognized strong bases and acids are not a lot. They're easily recognizable. Some strong bases are KOH, NaOH,Ba(OH)2,CsOH, Sr(OH)2,Ca(OH)2,LiOH, RbOH. Some Strong Acids are HI, HClO4, HCl, H2SO4, HNO3, HClO3.
- Sun Dec 02, 2018 11:49 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Tetrahedral vs. square-planar
- Replies: 6
- Views: 1828
Re: Tetrahedral vs. square-planar
a tetrahedral has 4 regions of electron density, while a square planar has six. A square planar is made up a 2D tetrahedral with a pair of lone pairs are at each end.
- Sun Dec 02, 2018 11:38 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: “Soapy” feel of bases
- Replies: 5
- Views: 2557
Re: “Soapy” feel of bases
Bases feel soapy because they dissolve the fatty acids and oils on your skin. When a base is mixed with the fatty acids, soap is produces. This is significant because its a characteristic of a base.
- Mon Nov 26, 2018 10:20 pm
- Forum: Hybridization
- Topic: bond angles and increasing s-character
- Replies: 2
- Views: 1230
Re: bond angles and increasing s-character
The s character basically means the percentage of sigma bond in a hybridization. In a linear lewis structure there is a hybridization of sp. This has an s character of 50% and a p character of 50%. The bond angle is 180. Now if we look at a trigonal planar lewis structure, there is a decreased bond ...
- Sun Nov 25, 2018 2:39 pm
- Forum: Hybridization
- Topic: BrF3
- Replies: 2
- Views: 1247
Re: BrF3
it is sp3d because BrF3 forms three bonds with flourine and has two lone pairs. This T- Shaped structure needs at least 5 orbitals to fit in the 10 electrons, so it uses a d orbital to accommodate it.
- Sun Nov 25, 2018 2:23 pm
- Forum: Hybridization
- Topic: Hybrid orbitals pointing to corners?
- Replies: 4
- Views: 269
Re: Hybrid orbitals pointing to corners?
Pointing to corners basically means that the arrow displaying a dipole moment points out toward the most electronegative atom. The atoms arrange themselves in a way that each one is the same distance apart and create geometrical shapes that have corners.
- Sun Nov 18, 2018 11:51 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VESPR Theory
- Replies: 3
- Views: 919
Re: VESPR Theory
The VSEPR theory can predict the geometry shape of a molecule by indicating the alignment of the atoms based on the repulsion among the pairs of electrons around a central atom.
- Sun Nov 18, 2018 3:19 pm
- Forum: Bond Lengths & Energies
- Topic: Dissociation Energy
- Replies: 4
- Views: 734
Re: Dissociation Energy
That is correct. The larger the atomic radius, the less dissociation energy is needed to break the bond. This is because a longer bond length between two atoms, resulting from the increased distance between two nuclei, requires less energy to be broken.
- Sun Nov 18, 2018 3:08 pm
- Forum: Sigma & Pi Bonds
- Topic: Amount of sigma bonds
- Replies: 6
- Views: 968
Re: Amount of sigma bonds
There can only be one sigma bond between two atoms and if theres another bond, its a pi bond. There can be up to two pi bonds and one sigma bond between two atoms in a molecule.
- Sun Nov 11, 2018 11:13 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: polarizing power of a cation
- Replies: 3
- Views: 393
Re: polarizing power of a cation
A cation has high polarizing power because they can exert a strong pull on the anions electrons. The smaller the radius, the closer the distance between the two ions, and the stronger the distortion of the electrons towards the cation. The trend in the periodic table is that it increases from left t...
- Sun Nov 11, 2018 11:04 pm
- Forum: Dipole Moments
- Topic: How do you draw dipole moments
- Replies: 6
- Views: 1037
Re: How do you draw dipole moments
A modern way to draw a dipole moment is also drawn by pointing an arrow towards the partial positive charge
- Mon Nov 05, 2018 11:42 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: When to multiply by 2
- Replies: 5
- Views: 972
Re: When to multiply by 2
Would we still multiply it by 2 if we are just given the velocity like 10 m/s?
- Mon Nov 05, 2018 11:30 am
- Forum: Lewis Structures
- Topic: Midterm Practice with Unpaired Electrons
- Replies: 2
- Views: 509
Re: Midterm Practice with Unpaired Electrons
Im pretty sure you are right if you are analyzing these molecules as atoms, however, if they are molecules, C2 would have to have a quadruple bond and the negative charge would indicate an extra unpaired electron.
- Sun Nov 04, 2018 4:07 pm
- Forum: Properties of Electrons
- Topic: Change in Energy
- Replies: 3
- Views: 700
Change in Energy
Is the change in energy in an electron still negative, even if it goes from N=1 to n=3?
- Sun Nov 04, 2018 4:00 pm
- Forum: Student Social/Study Group
- Topic: Radicals
- Replies: 3
- Views: 386
Re: Radicals
Does that mean that groups 1A and 7A are all radical?
- Sun Oct 28, 2018 9:55 pm
- Forum: Electronegativity
- Topic: Electronegativity vs Electron Affinity
- Replies: 4
- Views: 37215
Re: Electronegativity vs Electron Affinity
They are very similar but these terms cannot be used interchangeably because electron affinity is a property of atoms, while electronegativity is a property of atoms when they form bonds with other atoms.
- Sun Oct 28, 2018 9:44 pm
- Forum: Trends in The Periodic Table
- Topic: Atomic Radius
- Replies: 4
- Views: 439
Re: Atomic Radius
Adding electrons would only create a stronger pull of the electrons towards the nucleus if protons were added as well. The addition of electrons causes a electrostatic repulsion that makes the shell in an anion expand.
- Sun Oct 28, 2018 9:34 pm
- Forum: Trends in The Periodic Table
- Topic: Atomic Radii
- Replies: 2
- Views: 317
Re: Atomic Radii
Increasing the number of electrons would lead to the orbital expanding in ions. However, the periodic trend refers to neutral atoms, so protons are also added along with the electrons leading to a greater attraction between the nucleus and shell. This causes the shell to contract and the atom gets s...
- Sun Oct 21, 2018 9:50 pm
- Forum: Properties of Electrons
- Topic: Atomic Spectra
- Replies: 4
- Views: 477
Re: Atomic Spectra
An Atom emits light when it goes from a higher energy to a lower energy level. An electron absorbs energy when it is excited and moves to higher energy levels.
- Sun Oct 21, 2018 9:46 pm
- Forum: Properties of Light
- Topic: Equations
- Replies: 6
- Views: 655
Re: Equations
is one of the equations that I don't think will be given
- Sun Oct 21, 2018 9:40 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Test Question
- Replies: 8
- Views: 767
Re: Test Question
We're probably expected to understand electron configuration and how orbitals are structured in order to name the state of an electron
- Fri Oct 19, 2018 12:27 pm
- Forum: Einstein Equation
- Topic: Number of photons
- Replies: 7
- Views: 1134
Re: Number of photons
Would the number of photons affect the amount of energy produced at a certain wavelength?
- Fri Oct 19, 2018 12:19 pm
- Forum: Properties of Electrons
- Topic: Speed of an Electron (hw 1.43)
- Replies: 8
- Views: 4587
Re: Speed of an Electron (hw 1.43)
how would you model the atom in the second part of this question?
- Fri Oct 19, 2018 11:17 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Balmer series
- Replies: 1
- Views: 206
Balmer series
Lines in the Balmer series of the hydrogen spectrum are observed at 656.3, 486.1, 434.0, and 410.2 nm. What is the wavelength of the next line in the series?
im not sure how to approach this question
im not sure how to approach this question
- Thu Oct 18, 2018 11:01 am
- Forum: Photoelectric Effect
- Topic: wavelength
- Replies: 1
- Views: 278
wavelength
Lines in the Balmer series of the hydrogen spectrum are observed at 656.3, 486.1, 434.0, and 410.2 nm. What is the wavelength of the next line in the series?
I'm very confused on how to relate these wavelengths
I'm very confused on how to relate these wavelengths
- Wed Oct 10, 2018 11:23 pm
- Forum: Properties of Electrons
- Topic: Question 1.15 on homework
- Replies: 16
- Views: 10489
Re: Question 1.15 on homework
My way to approach this problem was to: 1. figure out the frequency using the wavelength of 102.6 nm and the formula v=c/lambda 2. then use the frequency and plug it into Rydberg formula 3. since the problem states its in the UV spectrum the initial energy should be 1 leaving n2 as the only undefine...
- Tue Oct 02, 2018 11:31 pm
- Forum: Empirical & Molecular Formulas
- Topic: MOLAR MASS
- Replies: 1
- Views: 303
MOLAR MASS
The molar mass of the metal hydroxide M(OH) is 74.10 g/mol.What is the molar mass of the sulfide of this metal?