## Search found 62 matches

Mon Mar 11, 2019 2:48 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Frequency Factor
Replies: 5
Views: 167

### Frequency Factor

What does the frequency factor mean?
Mon Mar 11, 2019 2:44 pm
Forum: First Order Reactions
Topic: Half-life Clarification
Replies: 5
Views: 198

### Re: Half-life Clarification

Yes. The half life equation depends on the reaction order.
Mon Mar 11, 2019 12:14 pm
Forum: Zero Order Reactions
Topic: Zero Order Reaction
Replies: 5
Views: 366

### Zero Order Reaction

What is an example of a zero order reaction?
Wed Mar 06, 2019 2:21 pm
Forum: Zero Order Reactions
Topic: General Meaning of "Zero Order" Reactions
Replies: 7
Views: 250

### Re: General Meaning of "Zero Order" Reactions

In a zero order reaction, the rate of the reaction does not depend on the concentration of the reactant.
Wed Mar 06, 2019 2:19 pm
Forum: Second Order Reactions
Topic: graph for second order
Replies: 7
Views: 300

### Re: graph for second order

The graph for the second order looks like a line with a positive slope.
Wed Mar 06, 2019 9:20 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E cell
Replies: 5
Views: 176

### E cell

What is the difference between E cell and E^o ?
Tue Feb 26, 2019 4:51 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6L9
Replies: 1
Views: 87

### 6L9

The equation for the anode part of the reaction is Fe^2+(aq)--> Fe^3+(aq) +1e-
Why does Fe^3+ come before Fe^2+ in the cell diagram?
Pt(s)I Fe^3+(aq), Fe^2+(aq)II
Tue Feb 26, 2019 12:49 pm
Forum: Van't Hoff Equation
Topic: Van't Hoff Equation
Replies: 3
Views: 392

### Re: Van't Hoff Equation

K varies by temperature, so the Van Hoff equation is used to calculate K at a different temperature. If you know delta H and the K value at one temperature, you can use the equation to find K at a different temperature.
Tue Feb 26, 2019 9:38 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 6L.3 7th Edition: Solve for E° values?
Replies: 1
Views: 104

### Re: 6L.3 7th Edition: Solve for E° values?

You can find the values in Appendix 2B.
Mon Feb 25, 2019 2:23 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Voltage
Replies: 1
Views: 54

### Re: Voltage

Voltage can be negative, but if it is negative the battery will not work.
Wed Feb 20, 2019 8:57 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Midterm Ice Table
Replies: 6
Views: 282

### Re: Midterm Ice Table

You can solve an equilibrium problem without using an approximation. Approximations act like a short cut. If the questions stated to not use an approximation, you would do the problem using the quadratic formula.
Wed Feb 20, 2019 4:49 pm
Forum: Balancing Redox Reactions
Topic: Salt Bridge
Replies: 4
Views: 163

### Salt Bridge

What is the purpose of the salt bridge?
Wed Feb 20, 2019 4:44 pm
Forum: Balancing Redox Reactions
Topic: Determining Oxidation State
Replies: 2
Views: 96

### Re: Determining Oxidation State

You know Fe lost 5 electrons because originally there are 5 Fe 2+ which has a total charge of 10+. After the reaction there is 5 Fe 3+ which has a total charge of 15+. In order to go from 10+ to 15+, 5 electrons must be lost.
Mon Feb 11, 2019 10:53 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Ideal Gas
Replies: 2
Views: 87

### Ideal Gas

What does an ideal gas mean?
Mon Feb 11, 2019 10:41 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Delta H
Replies: 3
Views: 162

### Re: Delta H

Delta H is equal to q when there is constant pressure.
Mon Feb 11, 2019 12:13 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Units for enthalpy
Replies: 6
Views: 238

### Re: Units for enthalpy

You can use either J or kJ. Both will be accepted on the test, but when the amount of J is above 1000, it is usually written in kJ.
Mon Feb 04, 2019 7:39 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: U
Replies: 7
Views: 207

### Re: U

U is a state property because the value is determined by its current state. A state property is not dependent on the path taken to obtain that state.
Mon Feb 04, 2019 2:02 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Degeneracy
Replies: 5
Views: 209

### Re: Degeneracy

Degeneracy is the number of ways of achieving a given energy state.
Mon Feb 04, 2019 1:59 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Equation for internal energy
Replies: 2
Views: 114

### Re: Equation for internal energy

q is the heat exchanged between the system and its surroundings.
Tue Jan 29, 2019 6:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 7th Ed. 4C3
Replies: 2
Views: 111

### Re: 7th Ed. 4C3

The solution manual says that in part a) Tf= 343K and in part b) Tf= 373K.
Tue Jan 29, 2019 6:02 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeter
Replies: 4
Views: 162

### Calorimeter

What is the purpose of a calorimeter and how does it work?
Mon Jan 28, 2019 7:54 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard State
Replies: 2
Views: 97

### Standard State

When finding the standard enthalpy of an equation, how can you make sure that everything is in standard state?
Tue Jan 22, 2019 3:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D.3 7th edition
Replies: 1
Views: 54

### Re: 6D.3 7th edition

Use an ICE chart and find the concentration of H30+ by using the given pH.
Tue Jan 22, 2019 12:38 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic vs. Exothermic
Replies: 8
Views: 342

### Endothermic vs. Exothermic

What is the difference between an endothermic reaction and an exothermic reaction?
Tue Jan 22, 2019 12:34 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Sig Figs of pKa
Replies: 2
Views: 1591

### Re: Sig Figs of pKa

It is the same rule for pKa because the rule applies whenever you take the log of something.
Wed Jan 16, 2019 9:35 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle- example from class
Replies: 3
Views: 162

### Re: Le Chatelier's Principle- example from class

If we increase N2 the reaction will proceed to the right so more product is formed.
If we increase NH3 the reaction will proceed to the left so more reactants are formed.
If we decrease H2 the reaction will proceed to the left so more reactants are formed.
Wed Jan 16, 2019 12:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Acids
Replies: 6
Views: 207

### Acids

How can you tell what is a weak acid vs. what is a strong acid?
Tue Jan 15, 2019 9:40 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction Quotient
Replies: 10
Views: 336

### Re: Reaction Quotient

K is used to describe a reaction that is at equilibrium. The reaction quotient is used to describe a reaction that is not at equilibrium. If Q is equal to K, the reaction is at equilibrium.
Wed Jan 09, 2019 6:41 pm
Forum: Ideal Gases
Topic: Reaction Quotient
Replies: 4
Views: 156

### Re: Reaction Quotient

The Reaction Quotient is calculated the same way that K is calculated. The equation is Q=[Products]/[Reactants]. The reaction quotient is used to determine which direction the reaction will proceed.
Wed Jan 09, 2019 10:08 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction Quotient
Replies: 5
Views: 244

### Re: Reaction Quotient

K is used to describe a reaction at equilibrium. The reaction quotient is used to describe a reaction that is not at equilibrium. If the reaction quotient is equal to K, you know that the reaction is at equilibrium.
Tue Jan 08, 2019 6:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc vs. Kp
Replies: 7
Views: 286

### Kc vs. Kp

How do we know when to write the equation for Kc vs. Kp when the question just asks to find the expression for K like in question 5G3?
Mon Dec 03, 2018 8:27 pm
Forum: Conjugate Acids & Bases
Topic: conjugate acids
Replies: 3
Views: 241

### Re: conjugate acids

The formula of the conjugate acid is CH3NH3+. You just add an H+.
Mon Dec 03, 2018 8:23 pm
Forum: Lewis Acids & Bases
Topic: Naming Acids
Replies: 2
Views: 157

### Naming Acids

How can you determine the name of an acid?
Mon Dec 03, 2018 11:19 am
Forum: Balancing Chemical Reactions
Topic: Aqueous compounds
Replies: 5
Views: 395

### Aqueous compounds

How can you tell if a compound is aqueous?
Tue Nov 27, 2018 2:46 pm
Forum: Hybridization
Topic: 2F.13 7th Ed
Replies: 4
Views: 209

### Re: 2F.13 7th Ed

The hybridization of CH2 and CH are sp2 because there are only three areas of electron density surrounding them. The C in CH2 has one bond connecting each of the two hydrogens and a double bond connecting it to the other carbon. The C in CH has one bond connecting it to the hydrogen, one double bond...
Mon Nov 26, 2018 11:16 am
Forum: Bond Lengths & Energies
Topic: 7th Edition 2D.13
Replies: 1
Views: 100

### Re: 7th Edition 2D.13

You know the order because triple bonds are shorter than double bonds, and double bonds are shorter than single bonds.
Mon Nov 26, 2018 9:39 am
Forum: Hybridization
Topic: Just Kind of Confused
Replies: 13
Views: 381

### Re: Just Kind of Confused

You can write it either way. Both are considered correct.
Tue Nov 20, 2018 12:56 pm
Forum: Lewis Structures
Topic: Electronegativity
Replies: 4
Views: 205

### Re: Electronegativity

The atom with the smallest electronegativity is typically the central atom because atoms with high electronegativity are more reluctant to share their electrons with other atoms and instead keep their lone pairs.
Mon Nov 19, 2018 2:45 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 3
Views: 65

### Bond Angles

What are the bond angles of a seesaw?
Mon Nov 19, 2018 9:40 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs. Angular
Replies: 3
Views: 148

### Bent vs. Angular

Is having a molecular shape that is bent the same as having a molecular shape that is angular?
Thu Nov 15, 2018 11:43 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape
Replies: 3
Views: 147

### Molecular shape

How does the molecular shape affect the boiling point?
Tue Nov 13, 2018 11:15 am
Forum: Dipole Moments
Topic: Van der Waals
Replies: 4
Views: 227

### Van der Waals

Do all molecules have Van der Waals forces?
Mon Nov 12, 2018 7:40 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Compounds 2D3
Replies: 2
Views: 169

### Re: Ionic Compounds 2D3

A rough guideline to determine if something is an ionic bond is to use electronegativity. If the electronegativity difference is greater than 2, it is likely an ionic bond. BaBr2 is more ionic than BeBr2 and BBr3 because the electronegativity difference is greater.
Thu Nov 08, 2018 3:57 pm
Forum: Dipole Moments
Topic: Polarizability
Replies: 5
Views: 172

### Polarizability

How can you tell the polarizability of a molecule?
Wed Nov 07, 2018 11:18 am
Forum: Dipole Moments
Topic: Interaction Potential Energy
Replies: 1
Views: 91

### Interaction Potential Energy

What is interaction potential energy? Why is it always negative?
Tue Nov 06, 2018 11:41 am
Forum: Octet Exceptions
Topic: Central atoms with more than 8 electrons
Replies: 3
Views: 241

### Re: Central atoms with more than 8 electrons

Any atom that is in the third period or below can have an expanded octet.
Wed Oct 31, 2018 5:10 pm
Forum: Octet Exceptions
Topic: Coordinate Covalent Bond
Replies: 2
Views: 132

### Coordinate Covalent Bond

What is a coordinate covalent bond? How does it relate to octet exceptions?
Tue Oct 30, 2018 2:41 pm
Forum: Resonance Structures
Topic: Lengths of bonds
Replies: 3
Views: 129

### Lengths of bonds

Why are double bonds shorter than single bonds?
Mon Oct 29, 2018 9:35 am
Forum: Trends in The Periodic Table
Topic: Electron affinity
Replies: 3
Views: 212

### Electron affinity

What is the difference between electron affinity and electronegativity?
Tue Oct 23, 2018 11:04 am
Forum: Administrative Questions and Class Announcements
Topic: TEST 3 during Thanksgiving week?
Replies: 5
Views: 344

### Re: TEST 3 during Thanksgiving week?

I think he updated the test and exam schedule because now it says Test 3 starts Tuesday November 27.
Mon Oct 22, 2018 10:38 pm
Forum: Administrative Questions and Class Announcements
Replies: 135
Views: 31317

Can anyone explain how to do number 7 on the Quantum World Worksheet 2 the way Professor Lavelle showed us in class? Here is the question. An excited hydrogen atom emits light with a frequency of 1.14 x 10^14 Hz to reach the energy level for which n=4. In what principle quantum level did the electro...
Mon Oct 22, 2018 8:46 pm
Forum: Properties of Electrons
Topic: Predicting Nodal Planes
Replies: 2
Views: 222

### Re: Predicting Nodal Planes

There are always 3 nodal planes for f orbitals.
Thu Oct 18, 2018 3:24 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 1
Views: 75

### Nodal Planes

How can you tell which orbitals have nodal planes?
Wed Oct 17, 2018 11:55 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Problem 1D 13
Replies: 2
Views: 105

### Re: Problem 1D 13

Question 1D 13 part d asks how many subshells are there in the shell with n=4. In this case there would be four subshells (4s, 4p, 4d, and 4f).
Tue Oct 16, 2018 6:00 pm
Forum: DeBroglie Equation
Topic: Mass of electrons
Replies: 3
Views: 131

### Re: Mass of electrons

I think it will be given.
Fri Oct 12, 2018 4:33 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Audio Visual Question 28
Replies: 1
Views: 59

### Audio Visual Question 28

The meter was defined in 1963 as 1,650,763.73 wavelengths of radiation emitted by krypton-86. What is the wavelength of this krypton-86 radiation?
Wed Oct 10, 2018 11:26 am
Forum: Properties of Light
Topic: Homework Question 1A15
Replies: 3
Views: 128

### Homework Question 1A15

In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6nm. Determine the values of n for the initial and final energy levels of the electron during the emissions of energy that leads to this spectral line.
Tue Oct 09, 2018 5:20 pm
Forum: Properties of Light
Topic: Homework Problem 1B9
Replies: 1
Views: 74

### Homework Problem 1B9

A lamp rated at 32. W (1W=1J/s) emits violet light of wavelength 420nm. How many moles of photons are emitted in 2.0 seconds?
Sun Oct 07, 2018 2:55 pm
Forum: Einstein Equation
Topic: Homework Question 1B7b
Replies: 2
Views: 229

### Homework Question 1B7b

Sodium vapor lamps emit yellow light of wavelength 589nm. How much energy is emitted by 5.00 mg of sodium atoms?
Wed Oct 03, 2018 8:23 pm
Forum: SI Units, Unit Conversions
Topic: Naming Compounds
Replies: 9
Views: 478

### Naming Compounds

Can someone explain how to write the formula of compounds.

For example, in question E9 it asks you to write the formula for magnesium sulfate heptahydrate.
Mon Oct 01, 2018 11:18 am
Forum: Limiting Reactant Calculations
Topic: Audio Visual Question 22
Replies: 3
Views: 188

### Audio Visual Question 22

According to the following equation 0.750 g of C6H9Cl3 is mixed with 1.000 kg of AgNO3 in a flask of water. A white solid, AgCl, completely precipitates out. What is the mass of AgCl produced? C6H9Cl3 + 3AgNO3 --> AgCl + C6H9(NO3)3 Molar Mass : C6H9Cl3 (187.50 g/mol), 3AgNO3 (169.88 g/mol), AgCL (14...
Sun Sep 30, 2018 9:26 am
Forum: SI Units, Unit Conversions
Topic: How does grading for discussion posts work?
Replies: 80
Views: 3812

### Re: How does grading for discussion posts work?

You can receive a maximum of 3 points per week, and you get a point every time you make a post or reply to a post. If you post 3 times per week, you will receive full credit.