## Search found 60 matches

Wed Mar 13, 2019 7:23 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics Plots
Replies: 5
Views: 476

### Re: Kinetics Plots

A straight line for ln(A) means the reaction is first order. For 1/A it means the reaction is second order. For A it means the reaction is zero order.
Wed Mar 13, 2019 7:19 pm
Forum: First Order Reactions
Topic: 7B.9
Replies: 2
Views: 138

### Re: 7B.9

If you use the equation you should get the right answer. I recommend rechecking your math as you probably put a decimal point in the wrong place.
Wed Mar 13, 2019 7:14 pm
Forum: First Order Reactions
Topic: Structure for activated complexes
Replies: 1
Views: 100

### Re: Structure for activated complexes

I don't think we will need to do that on the final exam.
Mon Mar 04, 2019 4:53 pm
Forum: Zero Order Reactions
Topic: Order distinction
Replies: 9
Views: 573

### Re: Order distinction

You can analyze the graph of the reaction or add the exponents of the rate law.
Mon Mar 04, 2019 4:52 pm
Forum: Zero Order Reactions
Topic: Different Orders
Replies: 5
Views: 204

### Re: Different Orders

The calculations are very different for different order reactions.
Mon Mar 04, 2019 4:50 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Replies: 73
Views: 4019

I think the drop in sessions are the best because you can come and go as you please.
Mon Feb 25, 2019 4:40 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Homework question
Replies: 3
Views: 146

### Re: Homework question

You have to write the redox half reactions to determine the number of moles of electrons transferred.
Mon Feb 25, 2019 4:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Homework questions [ENDORSED]
Replies: 2
Views: 156

### Re: Homework questions[ENDORSED]

A negative voltage is possible, but it means the reaction will not be spontaneous.
Mon Feb 25, 2019 4:32 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Recharging Batteries [ENDORSED]
Replies: 10
Views: 681

### Re: Recharging Batteries[ENDORSED]

Charging a battery requires supplying it with energy.
Thu Feb 21, 2019 4:28 pm
Forum: Balancing Redox Reactions
Topic: Oxidation States
Replies: 10
Views: 431

### Re: Oxidation States

Mn does not always have an oxidation state of 7+. That was only true for that particular example.
Thu Feb 21, 2019 4:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Reduction Potentials
Replies: 3
Views: 201

### Re: Reduction Potentials

I believe they are tested against hydrogen, as it is impossible to test only one element at a time. Hydrogen is considered to have a potential of 0.
Thu Feb 21, 2019 4:23 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 3
Views: 125

### Re: Salt Bridge

It allows ions to flow from one vessel to the other. It only allows certain ions to pass through and not others.
Mon Feb 11, 2019 4:37 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond enthalpies
Replies: 10
Views: 396

### Re: Bond enthalpies

You need to know the Lewis structure. Otherwise, you won't know how many bonds of each type there are.
Mon Feb 11, 2019 4:32 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: difference in states
Replies: 6
Views: 429

### Re: difference in states

It would affect the calculations though.
Mon Feb 11, 2019 4:30 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Midterm [ENDORSED]
Replies: 49
Views: 2227

### Re: Midterm[ENDORSED]

It can also be a good idea to practice doing math problems slowly and methodically. If you make one mistake on the wrong question, it can cost you severely.
Thu Feb 07, 2019 6:48 pm
Forum: Phase Changes & Related Calculations
Topic: Solids and Liquids
Replies: 5
Views: 190

### Re: Solids and Liquids

Solids and liquids have a constant volume. Also, pressure is really only used to describe gasses.
Thu Feb 07, 2019 6:39 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Chem 14B Midterm
Replies: 3
Views: 244

### Re: Chem 14B Midterm

Gibbs free energy is not going to be on the midterm.
Thu Feb 07, 2019 6:32 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb calorimeters vs polystyrene cup calorimeters
Replies: 2
Views: 129

### Re: Bomb calorimeters vs polystyrene cup calorimeters

The pressure of a normal calorimeter is always constant since it is open to the air.
Mon Jan 28, 2019 1:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law (Method 1)
Replies: 4
Views: 231

### Re: Hess's Law (Method 1)

You can do that if you want. Just make sure to add the right reactions. Sometimes a question will give you delta H for the reverse reaction instead and you will need to account for that.
Mon Jan 28, 2019 1:39 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpy Formation of an element
Replies: 4
Views: 202

### Re: Standard Enthalpy Formation of an element

Standard enthalpy of formation is the enthalpy used to create a compound from its elemental components. Since the elemental components are already in the elemental form, it does not take any enthalpy to create them from the elemental form.
Mon Jan 28, 2019 1:37 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Energy vs. Enthalpy
Replies: 2
Views: 94

### Re: Energy vs. Enthalpy

Yes, enthalpy is the heat energy plus the work used to expand. The energy needed for the reaction to occur is the activation energy.
Thu Jan 17, 2019 10:31 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 4
Views: 188

### Re: Le Chatelier's Principle

You could also increase the pressure.
Thu Jan 17, 2019 10:28 am
Forum: Ideal Gases
Topic: 6th edition 11.81
Replies: 2
Views: 141

### Re: 6th edition 11.81

You also have to calculate K using the equilibrium pressures.
Thu Jan 17, 2019 10:25 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook 7th edition 6E1
Replies: 1
Views: 48

### Re: Textbook 7th edition 6E1

That is a diprotic acid, meaning it can give off 2 protons per formula unit. The first ionization is when the first proton comes off and the second ionization is when the second one comes off. The acid is strong at first, but when it releases the first proton it becomes HSo4 which is a weak acid. Th...
Sun Jan 13, 2019 4:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp Units
Replies: 6
Views: 236

### Re: Kp Units

It does not matter.
Sun Jan 13, 2019 4:10 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Phases and Reaction Quotient (HW)
Replies: 3
Views: 164

### Re: Phases and Reaction Quotient (HW)

You can think of the solid ad liquid concentrations as being factored out and included in K.
Sun Jan 13, 2019 4:08 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: reaction quotient [ENDORSED]
Replies: 4
Views: 221

### Re: reaction quotient[ENDORSED]

The reaction quotient is calculated the same way as the equilibrium constant. If the reaction is at equilibrium, it is called K and if the reaction is not at equilibrium yet, it is called Q.
Wed Jan 09, 2019 8:57 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Applying Le Chatelier's principle
Replies: 2
Views: 101

### Re: Applying Le Chatelier's principle

In addition, the reaction rate will increase.
Wed Jan 09, 2019 8:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework problem 11.89 6th edition
Replies: 1
Views: 99

### Re: Homework problem 11.89 6th edition

It looks to me like the total pressure is about 30, but the question is not asking for the total pressure anyway.
Wed Jan 09, 2019 8:46 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Concentrations
Replies: 4
Views: 136

### Re: Equilibrium Concentrations

Use equilibrium concentrations to calculate K. Use initial concentrations to calculate Q.
Mon Dec 03, 2018 10:52 am
Forum: Polyprotic Acids & Bases
Topic: oxacids and carboxylic acids
Replies: 5
Views: 603

### Re: oxacids and carboxylic acids

I think it is probably possible for a carboxylic acid to be polyprotic. I don't see any reason why not.
Mon Dec 03, 2018 10:50 am
Forum: Polyprotic Acids & Bases
Topic: Polyprotic Question!
Replies: 12
Views: 1069

### Re: Polyprotic Question!

The first proton is released most easily. Successive protons are less likely to dissociate.
Mon Dec 03, 2018 10:30 am
Forum: Amphoteric Compounds
Topic: Examples
Replies: 6
Views: 241

### Re: Examples

(HSO4)-1
Wed Nov 28, 2018 10:45 am
Forum: Hybridization
Topic: pi bonds
Replies: 3
Views: 187

### Re: pi bonds

Pi bonds do not involve hybridization.
Wed Nov 28, 2018 10:41 am
Forum: Hybridization
Topic: Hybrid Orbitals Notation?
Replies: 2
Views: 85

### Re: Hybrid Orbitals Notation?

I'm not sure what that denotation is saying. Maybe try double checking what it says in the textbook in case you were reading it wrong.
Wed Nov 28, 2018 10:35 am
Forum: Hybridization
Topic: Ethene Hybrid Orbitals
Replies: 4
Views: 287

### Re: Ethene Hybrid Orbitals

It needs to maintain a unhybridized orbital so that it can form a double bond.
Tue Nov 20, 2018 11:26 am
Forum: Bond Lengths & Energies
Topic: Drawing resonance structures?
Replies: 6
Views: 281

### Re: Drawing resonance structures?

A test would usually tell you to either draw all resonance structures or just one of the resonance structures.
Tue Nov 20, 2018 11:24 am
Forum: Bond Lengths & Energies
Topic: Polarity of different bond lengths
Replies: 3
Views: 270

### Re: Polarity of different bond lengths

I think that it would have some effect, but it probably isn't something that will make a difference in this class.
Tue Nov 20, 2018 11:11 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Different-looking N — H bonds in the Lewis structure for Ammonia (NH3)
Replies: 3
Views: 197

### Re: Different-looking N — H bonds in the Lewis structure for Ammonia (NH3)

The bonds are all the same. They are just being shown in 3D. The dashed bond is going into the page and the conical shaped bond is coming out of the page.
Tue Nov 13, 2018 5:45 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Alternative version of formula
Replies: 7
Views: 624

### Re: Alternative version of formula

Yes, they both work and I think your formula is much easier to remember and use.
Tue Nov 13, 2018 5:39 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 8
Views: 445

### Re: Electronegativity

There are also many metals which are exceptions such as lead.
Tue Nov 13, 2018 5:30 pm
Forum: Sigma & Pi Bonds
Topic: Difference in bonds
Replies: 2
Views: 147

### Re: Difference in bonds

Sigma bonds are used for single bonds and pi bonds are used for everything else. However, double and triple bonds still have one sigma bond and the rest are pi bonds.
Wed Nov 07, 2018 10:58 am
Forum: Ionic & Covalent Bonds
Topic: Bond Lengths, Bond Order, and Bond Strength
Replies: 2
Views: 197

### Re: Bond Lengths, Bond Order, and Bond Strength

Bonds with a higher bond order are shorter than bonds with a lower bond order. Bond strength has to do with bond enthalpy, which we haven't learned yet. It is not necessarily related directly to bond order.
Wed Nov 07, 2018 10:54 am
Forum: Ionic & Covalent Bonds
Topic: Covalent attributes [ENDORSED]
Replies: 2
Views: 129

### Re: Covalent attributes[ENDORSED]

I think it depends on the family. For alkali metals, what you are saying is true, but for halogens, which form anions, it is not true.
Wed Nov 07, 2018 10:46 am
Forum: Coordinate Covalent Bonds
Topic: Coordinate Covalent Bond Definition
Replies: 14
Views: 1090

### Re: Coordinate Covalent Bond Definition

I don't believe this was covered in lecture. Usually, if you try to make a lewis structure and are struggling, there might be a dative or coordinate bond.
Tue Oct 30, 2018 10:40 am
Forum: Lewis Structures
Topic: Lewis Structure for Compounds
Replies: 2
Views: 90

### Re: Lewis Structure for Compounds

Glycine is a single molecule, but ammonium sulfate is an ionic compound comprised of two polyatomic ions.
Tue Oct 30, 2018 10:38 am
Forum: Lewis Structures
Topic: lewis structures
Replies: 3
Views: 82

### Re: lewis structures

Nitrogen, Boron, and Beryllium are exceptions. They can have less than 8 valence electrons.
Tue Oct 30, 2018 10:34 am
Forum: Lewis Structures
Topic: Lewis Structures with Polyatomic Species
Replies: 2
Views: 208

### Re: Lewis Structures with Polyatomic Species

The four H atoms are on the outside of N and since N has five valence electrons, there will be a bond connecting the two NH4 structures with the SO4 This is absolutely false. The nitrogen atom will make four bonds, one with each hydrogen. The fifth valence electron is lost because of the positive c...
Tue Oct 23, 2018 9:55 am
Forum: Administrative Questions and Class Announcements
Topic: test 2
Replies: 5
Views: 362

### Re: test 2

Probably not, but there will always be some basic things that you have to know, like what a mole is and stuff like that.
Tue Oct 23, 2018 9:54 am
Forum: Trends in The Periodic Table
Topic: Test 2 Topics Covered Question
Replies: 2
Views: 140

### Re: Test 2 Topics Covered Question

I would definitely read the F section. I would not be surprised to see Lavelle test us on something we haven't gone over.
Tue Oct 23, 2018 9:46 am
Forum: Trends in The Periodic Table
Topic: 1 F 11
Replies: 2
Views: 86

### Re: 1 F 11

I think the solutions manual may be wrong. That doesn't sound right to me at all.
Wed Oct 17, 2018 3:25 pm
Forum: Quantum Numbers and The H-Atom
Topic: Finding quantum numbers [ENDORSED]
Replies: 2
Views: 148

### Re: Finding quantum numbers[ENDORSED]

Everything said in the previous reply is true except the magnetic quantum number actually has different ranges for each value of the principle quantum number.
n=0 - ml=0
n=1 - ml=-1,0,1
n=2 - ml=-2,-1,0,1,2
n=3 - ml=-3,-2,-1,0,1,2,3
Wed Oct 17, 2018 3:22 pm
Forum: Quantum Numbers and The H-Atom
Topic: Hydrogen
Replies: 2
Views: 97

### Re: Hydrogen

The principal quantum levels of a Hydrogen atom correspond to different values of the principal quantum number n. Electrons with higher energy are found on higher energy levels.
Wed Oct 17, 2018 3:18 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1D.13
Replies: 2
Views: 126

### Re: 1D.13

How many of which quantum number? If you are talking about the magnetic quantum number, then only 0-4 are possible.
Fri Oct 12, 2018 9:31 am
Forum: Properties of Light
Topic: Do I need to memorize the Light Spectrum? [ENDORSED]
Replies: 13
Views: 393

### Re: Do I need to memorize the Light Spectrum?[ENDORSED]

I think you just need to know the order of the types of radiation and maybe the numbers for only the main ones like visible light, infrared, and ultraviolet.
Fri Oct 12, 2018 9:21 am
Forum: Properties of Light
Topic: Hz to S-1
Replies: 4
Views: 161

### Re: Hz to S-1

They are the exact same thing.
Fri Oct 12, 2018 9:19 am
Forum: Properties of Light
Topic: How light behaves
Replies: 8
Views: 337

### Re: How light behaves

Try to think of light as being either a wave or a particle instead of both at the same time. In some instances it acts like one and other times it acts like the other. For each circumstance, find out which one it is acting like and treat it that way for the rest of the problem.
Wed Oct 03, 2018 7:47 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Mole Definition
Replies: 5
Views: 245

### Re: Mole Definition

A mole is just like a dozen, but instead of signifying 12 of something, it signifies 6.022x10^23. The reason that this number is used is because 6.022x10^23 amu is equal to 1 gram. This helps make calculations simpler.
Wed Oct 03, 2018 7:41 pm
Forum: Significant Figures
Topic: Significant Figures
Replies: 6
Views: 408

### Re: Significant Figures

You must keep track of significant figures throughout your calculations, however you should not round until the end. If you need to, you can write down how many significant figures each number has as you go through each step, just remember to keep the numbers unrounded. Pay particular attention to l...
Wed Oct 03, 2018 7:31 pm
Forum: Limiting Reactant Calculations
Topic: Two Limiting Reactants
Replies: 6
Views: 268

### Re: Two Limiting Reactants

If 5 grams of reactant A react with 7 grams of reactant B, 12 grams of product must be produced because mass is conserved.