## 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: 298

### 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: 97

### 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: 324

### 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: 85

### 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: 321

### 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: 57

### 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: 83

### 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: 134

### 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: 96

### 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: 272

### 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: 154

### 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: 84

### 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: 136

### 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: 279

### 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: 198

### 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: 124

### 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: 267

### 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: 164

### 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: 175

### 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: 288

### 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: 1049

### 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: 222

### 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: 173

### Re: H and Q

Enthalpy is the amount of heat, $\Delta$ 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: 390

### 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: 42

### 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: 118

### 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: 32

### 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: 164

### 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: 124

### 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: 390

### 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: 299

### 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: 890

### 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: 380

### 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: 367

### 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: 358

### 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: 119

### 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: 585

### 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: 646

### 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: 252

### 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: 531

### 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: 141

### 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: 368

### 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: 279

### 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: 515

### 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: 142

### 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: 197

### 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: 494

### 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: 193

### 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: 436

### 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
Replies: 3
Views: 181

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: 16580

### 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
Replies: 4
Views: 171

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
Replies: 2
Views: 131

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: 217

### 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: 263

### Re: Equations

$E=hc/\lambda$ 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: 271

### 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: 646

### 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: 6
Views: 2839

### 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: 80

### 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
Thu Oct 18, 2018 11:01 am
Forum: Photoelectric Effect
Topic: wavelength
Replies: 1
Views: 123

### 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
Wed Oct 10, 2018 11:23 pm
Forum: Properties of Electrons
Topic: Question 1.15 on homework
Replies: 11
Views: 5010

### 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: 146

### 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?