## Search found 59 matches

Fri Mar 15, 2019 10:09 pm
Forum: General Rate Laws
Topic: approximation
Replies: 2
Views: 104

### approximation

When finding the rate law, when is it ok to approximate a number to a whole one?
Fri Mar 15, 2019 9:58 pm
Forum: General Rate Laws
Topic: 7A.13
Replies: 3
Views: 190

### Re: 7A.13

I think a way to do this is put in hypothetical concentrations for each number and see what exponent makes the rate double for each situation.
Sun Mar 10, 2019 12:14 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: negatives in the equation
Replies: 2
Views: 119

### negatives in the equation

In what context is the nFE equation negative/positive?(like for free energy vs E)
Sat Mar 09, 2019 5:14 pm
Forum: Van't Hoff Equation
Topic: pH and van’t hoff
Replies: 6
Views: 578

### pH and van’t hoff

why would the neutral ph change from 7 in a chemical reaction and how is that possible?
Sat Mar 09, 2019 5:12 pm
Forum: Zero Order Reactions
Topic: Zero order
Replies: 10
Views: 698

### Zero order

What would an example of a chemical reaction equation of a zero order reaction?
Sun Feb 24, 2019 10:49 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: higher entropy cis or trans
Replies: 8
Views: 1199

### Re: higher entropy cis or trans

I am still confused though, is the trans isomer only looking at the molecules 180 degrees apart?
Sat Feb 23, 2019 6:01 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Cell
Replies: 1
Views: 89

### Cell

If you are just given E for the half reactions is there any way to tell which one is the cathode and which one is the anode?
Sat Feb 23, 2019 5:59 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Replies: 4
Views: 215

How do we use use faradays constant in the equation for Gibbs free energy?
Tue Feb 19, 2019 2:50 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: What to do when temperature isn't given
Replies: 8
Views: 233

### What to do when temperature isn't given

When calculating the change in Gibbs free energy of the formation of a compound, is the temperature just at 25 degrees Celsius?
Sun Feb 17, 2019 12:24 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Free Energy
Replies: 1
Views: 87

### Free Energy

Why is the delta G for a spontaneous process negative always?
Sun Feb 17, 2019 12:23 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Fundamentals
Replies: 1
Views: 107

### Gibbs Free Energy Fundamentals

What happens when there is zero Gibbs free energy? Like when K=1 and R and P are in their standard state?
Sun Feb 17, 2019 12:20 am
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Derivations
Replies: 3
Views: 350

### Derivations

Can somene help me understand what we use the ln(K2/K1)=-(deltaH/R)[1/T2-1/T1] equation?
Sat Feb 16, 2019 9:37 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Converting to q rev
Replies: 4
Views: 214

### Converting to q rev

Even if the reaction you have is irreversible, do you still use change in entropy= qrev/T?
Sat Feb 16, 2019 9:36 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Pressure Equation
Replies: 7
Views: 454

### Pressure Equation

When would you use the -nRTln(P1/P2) equation?
Sat Feb 16, 2019 9:34 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: First Law
Replies: 3
Views: 151

### First Law

Are there any restrictions on when you can use delta nRT in place of PdeltaV?
Sat Feb 09, 2019 2:41 pm
Forum: Calculating Work of Expansion
Topic: Expansion work
Replies: 1
Views: 117

### Expansion work

Can anyone help me with this question?

How much work does 100 g of water do when it freezes at ) degrees Celsius and pushes back the metal wall of a pipe that exerts an opposing pressure of 1070 atm? The densities of water and ice at 0 degrees Celsius are 1.00g/cm^3 and .92 g/cm^3 respectively.
Thu Jan 31, 2019 7:40 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Reaction Enthalpy
Replies: 3
Views: 154

### Reaction Enthalpy

When a reaction goes from a solid to a liquid, why does delta H equal delta U?
Thu Jan 31, 2019 7:37 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Enthalpy
Replies: 6
Views: 170

### Enthalpy

Why is the enthalpy of bonds (delta H b) always greater than zero and endothermic?
Mon Jan 28, 2019 3:51 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Delta H
Replies: 4
Views: 167

### Delta H

What is the difference between Delta H and T? Today in Lecture Lavelle said that an increase in T would mean the reaction is exothermic, and that would mean that the delta H is negative, so how would that work?
Sun Jan 27, 2019 4:10 pm
Forum: Phase Changes & Related Calculations
Topic: reversible/irreversible
Replies: 8
Views: 225

### reversible/irreversible

Can someone help me clear up the difference between reversible and irreversible reactions and the difference in work?
Mon Jan 21, 2019 5:21 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculation Kc in terms of X
Replies: 1
Views: 77

### Calculation Kc in terms of X

For the equation Ni(CO4)<->Ni + 4CO, where x is the equilibrium concentration of CO, how would you put the equation in terms of X. The answer says that it would be x*4/(1.0-x/4) but how would you get the top to be x^4 ?
Mon Jan 21, 2019 12:36 pm
Forum: Administrative Questions and Class Announcements
Replies: 179
Views: 12685

I got .05 grams for number 2 on the acid base worksheet because I first found the hydronium concentration then I solved for X and from there multiplied the answer by the molar mass, and did not get .1. Can anyone help me on this?
Sun Jan 20, 2019 11:30 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Stoichiometric Coefficients
Replies: 4
Views: 169

### Stoichiometric Coefficients

Will we ever have to calculate the pH of a week acid/ base where the stoiciometric constant is not one, if so, are there any example and how would you go about solving the problem?
Sun Jan 20, 2019 11:27 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Salt in the Equation
Replies: 1
Views: 108

### Salt in the Equation

Are there any exceptions to the rule about salts/elements that do not change ph? Are all group 1 and 2 cations and, H, Br, and I the only elements that do not affect pH?
Wed Jan 16, 2019 3:38 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Weak Acids and Bases
Replies: 6
Views: 255

### Weak Acids and Bases

In class today Lavelle said that if you have a very small amount of a very weak acid, that changes the answer you get because if the concentration of H30+ is 10^-7 and you get the concentration at the end to be 10^-9, you have to do something different to get the correct answer? What would that be?
Sat Jan 12, 2019 5:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE tables
Replies: 2
Views: 92

### ICE tables

When calculating concentrations and the stoichiometric coefficients are not one, how would one account for that? Would you square the concentrations of multiply them by the coefficients?
Sat Jan 12, 2019 5:06 pm
Forum: Ideal Gases
Topic: Homework 6th edition Question 11.7
Replies: 1
Views: 62

### Homework 6th edition Question 11.7

When Looking at the flasks in question 11.7 in the 6th edition, the answer says that the third flask is in equilibrium, but I am wondering why because the third and fourth flasks both have the same number of dissociated and non-dissociated molecules? Can anyone help me with this question? The questi...
Tue Jan 08, 2019 8:09 pm
Forum: Ideal Gases
Topic: units in av focus topics
Replies: 1
Views: 105

### units in av focus topics

When calculation concentration in mol.m^-3, and you are given R in m^3 how would you do the conversions?
Thu Dec 06, 2018 12:32 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH of solutions
Replies: 1
Views: 97

### pH of solutions

When trying to find the pH of a solution that has both an acid and a base in it, would it just be the negative log of the molarity of the acid? Do you need to take into account the molarity of the base too?
Thu Dec 06, 2018 12:30 pm
Forum: Naming
Topic: Compound formula
Replies: 1
Views: 105

### Compound formula

How would you write out Bisethylenediaminediiodomanganese(IV) ion?
Thu Dec 06, 2018 12:29 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: number
Replies: 1
Views: 111

### number

How would you tell the coordination number of a heme? Is the coordination number the same thing as looking to how many bonds are to the central atom? If so, how does the coordination number relate to what kind of chelate it is?
Thu Nov 29, 2018 8:36 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: Dipole Induced Dipole
Replies: 1
Views: 38

### Dipole Induced Dipole

Can someone give me an example of a dipole-induced dipole molecule? I just need some help clarifying what they look like and how the charges affect each other.
Thu Nov 29, 2018 8:34 pm
Forum: Sigma & Pi Bonds
Topic: Sigma bonds
Replies: 6
Views: 321

### Sigma bonds

What do sigma bonds look like on an orbital?
Thu Nov 29, 2018 8:33 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Charge vs. Placement
Replies: 1
Views: 44

### Charge vs. Placement

When determining which cation/anion has more polarizing power/polarizability, which weighs more, charge or placement on the periodic table?
Sun Nov 25, 2018 12:08 am
Forum: Octet Exceptions
Topic: Exceptions
Replies: 3
Views: 386

### Exceptions

How come atoms like Boron and Aluminum are exceptions to the octet rule? Is there an easy way to remember exceptions?
Sun Nov 25, 2018 12:07 am
Forum: Lewis Structures
Topic: Lewis Structures
Replies: 2
Views: 119

### Lewis Structures

Can someone help me draw the N5+ Lewis Structure? I cannot figure it out.
Mon Nov 19, 2018 2:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: multiple sigma bonds
Replies: 4
Views: 214

### multiple sigma bonds

When forming double and triple bonds, there is only one sigma bond, is there a reason why its only possible to form one sigma bond in double and triple bonds?
Mon Nov 19, 2018 2:26 pm
Forum: Hybridization
Topic: breaking pi bonds
Replies: 1
Views: 114

### breaking pi bonds

What is an example of when pi bods break in the natural world if there are any?
Fri Nov 16, 2018 5:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: see saw
Replies: 2
Views: 120

### see saw

Can someone help explain how the see saw shape comes about and why the 90 degree angles are more stable?
Fri Nov 16, 2018 5:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Octahedral
Replies: 4
Views: 166

### Octahedral

What is the VSEPR notation for a molecule with an octahedral shape?
Fri Nov 16, 2018 5:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: sigma and pi bonds
Replies: 1
Views: 97

### sigma and pi bonds

I understand how sigma bonds allow for rotation and pi bonds do not, but could someone help me figure out how in class today, he said that a triple bond between two N atoms would have one sigma bond and two pi bonds?
Sat Nov 10, 2018 5:43 pm
Forum: Dipole Moments
Topic: Dipole Induced Dipole
Replies: 2
Views: 101

### Dipole Induced Dipole

Can anyone explain more about dipole-induced dipole? I understand how it is a dipole with an atom that does not form one, and then the dipole causes the other atom to become a dipole, but could someone explain to me how this happens?
Sat Nov 10, 2018 5:39 pm
Forum: Resonance Structures
Topic: Bond Lengths
Replies: 6
Views: 589

### Bond Lengths

Will we ever have to find exact bond length? Or do we just need to know trends and how they all average?
Sat Nov 10, 2018 5:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shapes
Replies: 5
Views: 238

### Shapes

Are all molecules with four bonding pairs tetrahedral? What makes the difference if they are not?
Mon Nov 05, 2018 11:55 pm
Forum: Ionic & Covalent Bonds
Topic: Bond Length
Replies: 8
Views: 293

### Bond Length

Can someone help clear up how to find different bond lengths in an atom?
Mon Nov 05, 2018 11:54 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: More Lewis Structure Help
Replies: 1
Views: 115

### More Lewis Structure Help

What is the Lewis Structure of ethanol: CH3CH2OH?
Mon Nov 05, 2018 11:53 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Lewis Structures
Replies: 1
Views: 85

### Lewis Structures

Can someone help me draw the lewis structure for potassium phosphide?
Sat Oct 27, 2018 3:47 pm
Forum: Lewis Structures
Topic: Order in Drawing Lewis Structures
Replies: 2
Views: 54

### Order in Drawing Lewis Structures

When an atom of an element does not have an octet, is there a specific side that the unpaired electrons (dots) should be drawn on? Or does it matter?
Sat Oct 27, 2018 3:43 pm
Forum: Lewis Structures
Topic: When electrons do no pair in orbitals:
Replies: 2
Views: 50

### When electrons do no pair in orbitals:

Can anyone help explain why some electrons are not paired in orbitals even if there are an even number of electrons? I am still a little bit confused.
Sat Oct 27, 2018 3:09 pm
Forum: Photoelectric Effect
Topic: Frequency of light
Replies: 2
Views: 134

### Frequency of light

Is there any surface that would emit electrons when the light being shown on it is visible light?
Sat Oct 20, 2018 3:03 pm
Forum: *Shrodinger Equation
Topic: Double Derivative and Shrodinger Equation
Replies: 1
Views: 157

### Re: Double Derivative and Shrodinger Equation

I believe he was talking about how the wave function of an electron looks like the sin function and if you take the double derivative you get -sin so that corresponds to how the hamiltonian (H in the equation) ends up equaling the energy of the electron (E) when you multiply both by psi? Can someone...
Sat Oct 20, 2018 2:57 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: angular node
Replies: 1
Views: 26

### angular node

Is an angular node the same thing as a nodal plane?
Sat Oct 20, 2018 2:55 pm
Forum: Quantum Numbers and The H-Atom
Replies: 1
Views: 107

Can someone help clear up if the atomic radius gets bigger when electrons move from the s orbital to either the p,d,or f orbitals? I think the radius stays the same but just want clarification?
Mon Oct 15, 2018 11:48 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Replies: 4
Views: 161

Is the negative symbol in front of the equation just a symbol that there is an energy decrease, and the actual energy of each level is still positive, or is there another explanation?
Mon Oct 15, 2018 11:47 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Absorption/Emission
Replies: 4
Views: 135

### Re: Absorption/Emission

This is confusing terminology to me too, but I believe spectrum emission is when the actual line shows up and spectrum absorption is where all colors are absorbed so there is no line, but I am not sure either. Can someone help clear this up?
Mon Oct 15, 2018 11:42 am
Forum: DeBroglie Equation
Topic: Mass of electrons
Replies: 4
Views: 214

### Mass of electrons

When calculating the mass of an electron, why is the SI unit in kg and not grams? Wouldn't grams make more sense?
Sat Oct 06, 2018 12:11 am
Forum: Limiting Reactant Calculations
Topic: Calculating Maximum Mass
Replies: 5
Views: 685

### Re: Calculating Maximum Mass

I am also confused as to how to go about this problem. It seems to me that it is a dilution equation followed by a limiting reactant equation but I am confused as to how to do the limiting reactant problem when it is a solution. Can anyone help?
Thu Oct 04, 2018 6:18 pm
Forum: Limiting Reactant Calculations
Topic: Limiting reactant [ENDORSED]
Replies: 2
Views: 105

### Limiting reactant[ENDORSED]

I understand that even when gram amounts for different reactants differ, it is not automatically the smallest one that becomes the limiting reactant, but what is the reason that that is the case?
Wed Oct 03, 2018 11:35 am
Forum: Empirical & Molecular Formulas
Topic: Molar Mass of Ions
Replies: 1
Views: 128

### Molar Mass of Ions

When trying to find the individual molar mass of ions in a chemical formula, would we first calculate the mass percentage that the ions have in the formula and then calculate the molar mass?