## Search found 72 matches

Fri Mar 15, 2019 8:50 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: homework problem 15.61
Replies: 1
Views: 100

### homework problem 15.61

The rate constant of the fi rst-order reaction 2 N2O(g) S
2 N2(g)  O2(g) is 0.76 s1 at 1000. K and 0.87 s1 at 1030. K.
Calculate the activation energy of the reaction.

the solutions manual uses the gas constant in terms of kJ. is this necessary? or can we use the gas constant in terms of J?
Fri Mar 15, 2019 8:42 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 15.61 equation
Replies: 3
Views: 428

### Re: 15.61 equation

is the second equation necessary to use? would the first equation produce the same answer?
Fri Mar 15, 2019 7:49 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: intermediates
Replies: 4
Views: 112

### intermediates

do you include intermediates in the rate law for a certain step?
Fri Mar 15, 2019 7:30 pm
Forum: Second Order Reactions
Topic: 15.39a - "0.37[A]o"
Replies: 2
Views: 321

### Re: 15.39a - "0.37[A]o"

i figured it out. That information pertains to the second part of the problem. it finds the concentration of A to put into the rate law equation and solve for t. i dont think it has anything to do with part a.
Fri Mar 15, 2019 7:22 pm
Forum: Second Order Reactions
Topic: 15.39a - "0.37[A]o"
Replies: 2
Views: 321

### Re: 15.39a - "0.37[A]o"

i am also confused by this.. the concentrations used to find that answer of part a is from the information given in part b
Thu Mar 14, 2019 11:18 pm
Forum: First Order Reactions
Topic: integrated rate laws
Replies: 3
Views: 189

### Re: integrated rate laws

thank you so much!
Thu Mar 14, 2019 10:32 pm
Forum: First Order Reactions
Topic: integrated rate laws
Replies: 3
Views: 189

### integrated rate laws

how do you know which integrated rate law to use in a problem? that is... the ln equation vs the e equation? if that makes sense.
Thu Mar 14, 2019 3:38 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: collision theory
Replies: 2
Views: 154

### Re: collision theory

thank you !!
Thu Mar 14, 2019 12:24 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: collision theory
Replies: 2
Views: 154

### collision theory

is collision theory going to be on the final?
Thu Feb 28, 2019 5:49 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: water in cell diagram
Replies: 1
Views: 84

### water in cell diagram

Is water (H2O) included in the cell diagram if it is within the half reaction? Or do you leave it out?
Wed Feb 27, 2019 6:41 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: platinum [ENDORSED]
Replies: 6
Views: 318

### platinum[ENDORSED]

how do you know which side to add platinum on in a cell diagram?
Wed Feb 27, 2019 5:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: calc reaction gibbs free energy
Replies: 1
Views: 98

### calc reaction gibbs free energy

when calculating reaction gibbs free energy, why do the moles not cancel out in the end? when you multiply by the amount of moles?
Mon Feb 25, 2019 10:27 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E not
Replies: 2
Views: 142

### E not

What is E not and how is it different from E?
Mon Feb 25, 2019 10:26 pm
Forum: Balancing Redox Reactions
Topic: oxidation number
Replies: 2
Views: 104

### oxidation number

how do you find the oxidation number of an element?
Mon Feb 25, 2019 10:25 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 1
Views: 71

### salt bridge

what is the necessity of the salt bridge/what does it do?
Mon Feb 25, 2019 10:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 5
Views: 293

### salt bridge

what is the necessity of the salt bridge/what does it do?
Mon Feb 25, 2019 10:24 pm
Forum: Balancing Redox Reactions
Topic: Gibbs free energy
Replies: 1
Views: 106

### Gibbs free energy

How does Gibbs free energy pertain to electrochemistry?
Wed Feb 20, 2019 9:15 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: entropy
Replies: 4
Views: 320

### entropy

What is the difference between entropy and enthalpy?
Wed Feb 20, 2019 9:14 pm
Forum: Calculating Work of Expansion
Topic: expansion
Replies: 2
Views: 139

### expansion

How do you know if a system has done expansion work or not?
Wed Feb 20, 2019 6:49 pm
Forum: Ideal Gases
Topic: units
Replies: 15
Views: 591

### units

I got marked down for putting "bar" in my K value on the midterm. Does anyone know why this is?
Sat Feb 09, 2019 5:37 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: MJ
Replies: 1
Views: 157

### MJ

In the textbook, it refers to a measurement of MJ? would that be milijoules? or megajoules? I have never seen that before.
Fri Feb 08, 2019 5:15 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity
Replies: 1
Views: 111

### Heat capacity

when would be the appropriate time to use the simple heat capacity equation instead of specific/molar?
Fri Feb 08, 2019 4:56 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: ideal gas volume
Replies: 1
Views: 81

### ideal gas volume

In the textbook, it says that U is independent of volume bc its an ideal gas. I am confused on why this is. When dealing with ideal gasses, do you ignore the volume when trying to find internal energy?
Mon Feb 04, 2019 1:48 pm
Forum: Calculating Work of Expansion
Topic: Degeneracy
Replies: 6
Views: 326

### Degeneracy

Can someone please explain the concept and how to determine degeneracy?
Mon Feb 04, 2019 1:47 pm
Forum: Calculating Work of Expansion
Topic: Residual entropy
Replies: 1
Views: 111

### Residual entropy

Can someone please explain when to use the equation for positional residual entropy?
Mon Feb 04, 2019 1:46 pm
Forum: Calculating Work of Expansion
Topic: Reversible expansion
Replies: 1
Views: 100

### Reversible expansion

Can someone please explain when an isothermal expansion would occur?
Mon Jan 28, 2019 1:22 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific heat capacity
Replies: 3
Views: 168

### Specific heat capacity

How is the specific heat capacity determined?
Mon Jan 28, 2019 1:21 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity
Replies: 1
Views: 103

### Heat capacity

How is the heat capacity determined?
Mon Jan 28, 2019 1:20 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Extensive vs intensive
Replies: 2
Views: 109

### Extensive vs intensive

What is the difference between an intensive and extensive property?
Wed Jan 23, 2019 1:21 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State property
Replies: 3
Views: 137

### State property

Can someone please explain what a state property is?
Wed Jan 23, 2019 1:20 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Exothermic and endothermic
Replies: 3
Views: 245

### Exothermic and endothermic

What is the difference between an endothermic reaction and an exothermic reaction?
Sun Jan 20, 2019 11:08 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Lecture notes
Replies: 2
Views: 766

### Lecture notes

Can someone please post the lecture notes from Friday!
Sun Jan 13, 2019 4:06 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: reaction quotient [ENDORSED]
Replies: 4
Views: 221

### reaction quotient[ENDORSED]

Can someone please explain how and when to use the reaction quotient and the difference between the reaction quotient and concentration?
Sun Jan 13, 2019 4:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: converting between partial pressure and concentration
Replies: 2
Views: 1830

### converting between partial pressure and concentration

Can someone please explain to me how to convert between partial pressure and concentration?
Sun Jan 13, 2019 4:03 pm
Forum: Ideal Gases
Topic: When is pv=nrt used? [ENDORSED]
Replies: 5
Views: 232

### When is pv=nrt used?[ENDORSED]

Can someone please explain to me when the ideal gas law is used?
Sat Dec 08, 2018 10:07 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 11589

### Re: FINAL PRACTICE - Lyndon's Churro Review Session[ENDORSED]

for number 34 you have to find the limiting reagent of the acid and base essentially. CaO dissociates to Ca2+ and O2-, and think of O2- + H2O -> 2OH- . So 1 mol CaO is equal to 2 mol OH-, maybe that's your error? Okay.. so you don't subtract the CaO concentration from the HCl concentration? you jus...
Sat Dec 08, 2018 9:24 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 11589

### Re: FINAL PRACTICE - Lyndon's Churro Review Session[ENDORSED]

Can someone please explain how to do number 34? I understand that they neutralize each other, but I'm not exactly sure on what steps to use to find the answer
Sat Dec 08, 2018 9:16 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 11589

### Re: FINAL PRACTICE - Lyndon's Churro Review Session[ENDORSED]

bonnie_schmitz_3K wrote:I think I understand the basis of how to do number 34, but I keep getting a pH of 2.10. Did anyone else make the error same/know what my error is?

I'm making that error, but I don't know what the issue is.
Sat Dec 08, 2018 8:27 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 11589

### Re: FINAL PRACTICE - Lyndon's Churro Review Session[ENDORSED]

Can someone please explain number 28?
Sat Dec 08, 2018 7:58 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 11589

### Re: FINAL PRACTICE - Lyndon's Churro Review Session[ENDORSED]

Can someone please explain why in number 21 the oxidation number for iron is 2+?
Sat Dec 08, 2018 6:57 pm
Forum: Student Social/Study Group
Topic: Practice Final
Replies: 2
Views: 505

### Practice Final

Does anyone know where to find a practice final? Other than the churro practice final?
Sat Dec 08, 2018 6:53 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Ka
Replies: 1
Views: 95

### Ka

Will we have to use the Ka formula on the final? What is an example of a problem that asks to use that formula?
Sat Dec 08, 2018 6:16 pm
Forum: Naming
Topic: CN Charge
Replies: 4
Views: 371

### CN Charge

Mon Dec 03, 2018 8:27 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Ka
Replies: 1
Views: 101

### Ka

When would you use the Ka calculation?
Mon Dec 03, 2018 8:26 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: ph vs pOH
Replies: 5
Views: 273

### ph vs pOH

What is the difference between ph and pOH?
Mon Dec 03, 2018 8:24 pm
Forum: Conjugate Acids & Bases
Topic: conjugate acids
Replies: 3
Views: 264

### conjugate acids

Can someone help me write the formula for the conjugate acids of CH3NH2 and methylamine
Mon Dec 03, 2018 8:22 pm
Forum: Conjugate Acids & Bases
Topic: Ion concentration
Replies: 2
Views: 126

### Ion concentration

Can someone please explain how to determine the ion concentrations in strong acids/bases?
Mon Dec 03, 2018 8:20 pm
Forum: Bronsted Acids & Bases
Topic: Difference
Replies: 2
Views: 104

### Difference

Can someone please explain to me the difference between Lewis acids/bases and bronsted?
Mon Dec 03, 2018 8:18 pm
Forum: Amphoteric Compounds
Topic: Definition
Replies: 6
Views: 253

### Definition

Can someone please explain and define amphoteric?
Sun Nov 25, 2018 5:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sigma vs pi bonds
Replies: 7
Views: 342

### Sigma vs pi bonds

Can someone please explain to me the difference between sigma and pi bonds?
Sun Nov 25, 2018 5:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole
Replies: 2
Views: 147

### Dipole

Can someone please explain to me what exactly dipole means?
Sun Nov 25, 2018 5:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Xenon Tetrafluoride
Replies: 3
Views: 191

### Xenon Tetrafluoride

Will someone please explain to me how Xenon in Xenon tetrafluoride has 6 regions of electron density?
Mon Nov 19, 2018 1:52 pm
Forum: Sigma & Pi Bonds
Topic: Sigma and pi bonds
Replies: 2
Views: 143

### Sigma and pi bonds

Can someone please explain the difference between sigma bonds and pi bonds? I am very confused.
Mon Nov 19, 2018 1:49 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 8
Views: 2653

### Formal Charge

Can someone explain the other way to determine the formal charge? The formula used in class confuses me and I am aware there is another, clearer way!
Mon Nov 19, 2018 1:48 pm
Forum: Hybridization
Topic: Hybridized orbitals
Replies: 1
Views: 53

### Hybridized orbitals

Can someone please explain how the one s orbital and one p orbital creates the 2sp hybridized orbitals?
Mon Nov 19, 2018 1:47 pm
Forum: Hybridization
Topic: electron density in regards to # of hybrid orbitals
Replies: 4
Views: 201

### electron density in regards to # of hybrid orbitals

Can someone please explain to me how the # of hybrid orbitals indicates the regions of electron density?
Mon Nov 19, 2018 1:44 pm
Forum: Hybridization
Topic: 4.33 Homework Problem
Replies: 2
Views: 93

### 4.33 Homework Problem

Can someone please explain this homework problem?
"State the hybridization of the atom in boldface type in each of the following molecules:
a) BeCl2 (Be)
b) BH3 (B)
c) BH4- (B)
d) SiF4 (Si)
Thank you !!
Mon Nov 19, 2018 1:41 pm
Forum: Lewis Structures
Topic: Lewis Structure for Ammonium chloride
Replies: 3
Views: 1538

### Re: Lewis Structure for Ammonium chloride

thank you so much!! it makes sense now.
Mon Nov 19, 2018 1:41 pm
Forum: Ionic & Covalent Bonds
Topic: Bond Lengths
Replies: 10
Views: 589

### Bond Lengths

Can someone explain how to determine the bond lengths given that the single bond length is 140pm and the double bond is 120pm in a nitrate structure?
Mon Nov 19, 2018 1:38 pm
Forum: Lewis Structures
Topic: Lewis Structure of BrO3-
Replies: 3
Views: 5747

### Lewis Structure of BrO3-

Can someone please help me with the lewis structure of BrO3-? I don't understand where the double bonds come in.
Mon Nov 19, 2018 1:36 pm
Forum: Trends in The Periodic Table
Topic: Ionization energy
Replies: 4
Views: 425

### Ionization energy

Can someone please explain why Na has a lower first ionization energy compared to Mg?
Mon Nov 19, 2018 1:35 pm
Forum: Photoelectric Effect
Topic: Speed vs frequency
Replies: 2
Views: 448

### Speed vs frequency

Can someone please explain, comment, and show that the speed, V, of the ejected electron and the frequency, v, of the incoming radiation are related by E=hv=l + 1/2mV^2.
Mon Nov 19, 2018 1:33 pm
Forum: Photoelectric Effect
Topic: Difference between ionization energy and threshold energy
Replies: 1
Views: 447

### Difference between ionization energy and threshold energy

What is the difference between ionization energy and threshold energy, if there is one?
Mon Nov 19, 2018 1:30 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Degeneracy
Replies: 4
Views: 2551

### Degeneracy

Can someone please explain exactly what degeneracy means? I am having a hard time understanding it.
Mon Nov 19, 2018 1:29 pm
Forum: Balancing Chemical Reactions
Topic: Why do we balance chemical equations?
Replies: 13
Views: 1364

### Why do we balance chemical equations?

For the question that asks why do we balance chemical equations, what was the exact answer that was desired? Thank you!
Mon Nov 19, 2018 1:27 pm
Forum: Empirical & Molecular Formulas
Topic: Determining Empirical formula
Replies: 4
Views: 464

### Determining Empirical formula

Can someone help me start the problem of finding the empirical formula when given molecules instead of atoms. For example, the question asks to find the empirical formula given 1.811 g of CO2 and 0.3172 g of H2O. Thank you!
Mon Nov 19, 2018 1:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lewis Structure of OSbCL3 and shape
Replies: 2
Views: 65

### Lewis Structure of OSbCL3 and shape

How do I determine the lewis structure and shape of the molecule OSbCL3?
Mon Nov 19, 2018 1:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles of H3O+
Replies: 2
Views: 74

### Bond angles of H3O+

Can someone please help me determine the bond angles at the central atom of the hydronium ion, H3O+? Thank you.
Mon Nov 19, 2018 1:18 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework This Week
Replies: 1
Views: 100

### Homework This Week

Does anyone know if there is homework due this week in sections?
Sun Nov 11, 2018 11:45 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs Nonpolar
Replies: 5
Views: 338

### Polar vs Nonpolar

How do you determine if the molecule is polar or non polar? Do you determine it from the Lewis structure or are there other steps involved?
Sun Nov 11, 2018 11:42 am
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.12 Homework Problem
Replies: 1
Views: 466

### 4.12 Homework Problem

Can someone please explain to me how they got the Lewis Structure for PF4-, and the VSEPR formula for that species, and how to predict the shape based off of that?
Sun Nov 04, 2018 9:58 pm
Forum: Lewis Structures
Topic: Lewis Structure for Ammonium chloride
Replies: 3
Views: 1538

### Lewis Structure for Ammonium chloride

Can someone please explain to me why the Cl- is not connected to the ammonium molecule?