## Search found 39 matches

Sat Mar 17, 2018 9:54 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrodes
Replies: 3
Views: 311

### Electrodes

Can someone clarify when its necessary to add an electrode (like Pt) to a cell?
Thu Mar 15, 2018 9:50 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Practice final problem
Replies: 2
Views: 330

### Re: Practice final problem

NVM!! I wasn't thinking. I understand
Thu Mar 15, 2018 9:42 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Practice final problem
Replies: 2
Views: 330

### Practice final problem

Can anyone explain how they got the change in temperature in part B?
Thu Mar 15, 2018 8:32 pm
Forum: *Alkanes
Topic: Organic chemistry [ENDORSED]
Replies: 3
Views: 660

### Organic chemistry[ENDORSED]

Will we be responsible for naming organic molecules? What parts of organic chemistry will we be responsible for?
Mon Mar 12, 2018 11:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Discussion Sections
Replies: 2
Views: 273

### Discussion Sections

Do discussion sections meet this week?
Mon Mar 05, 2018 8:47 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: derivations
Replies: 2
Views: 193

### derivations

will we have to know how to derive integrated rate laws for this weeks test?
Mon Mar 05, 2018 6:22 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: rate constant vs rates
Replies: 2
Views: 191

### rate constant vs rates

why does increasing the concentration of reactants cause the rate to increase but it doesn't affect the rate constant ?
Mon Mar 05, 2018 5:44 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: 15.19
Replies: 3
Views: 285

### 15.19

Can someone explain how to figure out the rate law of the reaction when you are given a+b+c--> products and a chart of experiments. How do you know what experiments to look at and how do you use them?
Sun Feb 25, 2018 11:42 pm
Forum: General Rate Laws
Topic: Rate of Reaction
Replies: 4
Views: 262

### Rate of Reaction

Can someone explain why -d[NO2]/dt=d[NO]/dt=2 d[O2]/dt
I'm confused about the 2 before the d[O2]/dt
Sun Feb 25, 2018 11:07 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Tangent line
Replies: 4
Views: 300

### Re: Tangent line

What is the ideal place to take the tangent line from then? How do you decide where to take the tangent line from?
Sun Feb 25, 2018 10:56 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Tangent line
Replies: 4
Views: 300

### Tangent line

When we're trying to determine the rate of a reaction and want to draw a line tangent to the curve would it matter where we take the tangent line from (at the beginning, end or middle of the curve)?
Sun Feb 25, 2018 9:47 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics vs Thermodynamics
Replies: 7
Views: 469

### Kinetics vs Thermodynamics

Is there a relationship between Kinetics and Thermodynamics? If something is kinetically stable, is it thermodynamically unstable, stable or is there no relationship between both?
Mon Feb 19, 2018 6:41 pm
Forum: Balancing Redox Reactions
Topic: Balanced Redox Reactions
Replies: 2
Views: 188

### Balanced Redox Reactions

When balancing redox reactions and we have to add water to the reaction does it matter where water is added (product or reactants side)? I was reading the text posted on the class website and it says: "Because there are four oxygen atoms in MnO4- that are not present in the final Mn2+ form, we ...
Sat Feb 17, 2018 9:07 pm
Forum: Balancing Redox Reactions
Topic: Test #2
Replies: 5
Views: 313

### Test #2

Does anyone know what exactly is going to be on the second test this week? Will any specific topics be excluded?
Sat Feb 17, 2018 12:08 am
Forum: Balancing Redox Reactions
Topic: Basic vs Acidic Conditions
Replies: 2
Views: 376

### Basic vs Acidic Conditions

Is there a way to tell whether we should balance an equation under acidic conditions as opposed to basic conditions, without it being explicitly stated in the directions?
Fri Feb 16, 2018 9:08 pm
Forum: Balancing Redox Reactions
Topic: 14.3 Balancing redox reactions
Replies: 2
Views: 208

### 14.3 Balancing redox reactions

a)Cl2 + S2O3(-2) --->Cl (-1) + SO4 (-2)

I am trying to balance the reaction and so far I have Cl2+2e-->2Cl- and S2O3(-2)+5H2O---> 2SO4 (-2) + 10H+
How do I finish balancing: S2O3(-2) + 5H2O---> 2SO4 (-2) + 10H+
Mon Feb 12, 2018 6:33 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: partial pressure units
Replies: 1
Views: 120

### partial pressure units

When we are calculating Gibbs free energy, do we have to convert partial pressures given in bar to atm? Does it matter?
Sun Feb 04, 2018 11:00 pm
Forum: Van't Hoff Equation
Topic: Friday Lecture:
Replies: 2
Views: 363

### Friday Lecture:

I know we were going to discuss free energy on Friday, but what else did Lavelle go over? I wasn't able to attend lecture and am trying to catch up and watch videos on the subject if anyone can please give me details on what i should review I'd appreciate it.
Sun Feb 04, 2018 10:38 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.27 Entropy
Replies: 3
Views: 249

### 9.27 Entropy

How would I explain which molecule HBr or HF has a higher molar entropy? I know Br is heavier (higher atomic weight) than Fluorine but how do I connect that idea to this question? Is there any actual calculations that I can do to figure this out?
Sun Feb 04, 2018 9:49 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: 9.25
Replies: 3
Views: 240

### Re: 9.25

Would we have to accurately draw the molecule with wedges and dashes to depict the 3D structure of the molecule or would it not matter?
Fri Jan 26, 2018 11:59 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy (9.11) [ENDORSED]
Replies: 1
Views: 102

### Entropy (9.11)[ENDORSED]

When solving problems for changes in entropy when given pressure values, would we need to show the derivation of the entropy equation for changes in pressure before solving the problem or would it suffice to explain that I used delta S=n*R*ln(p1/p2) because of the relationship between pressure and v...
Fri Jan 26, 2018 11:15 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.13 Entropy Change
Replies: 2
Views: 151

### 9.13 Entropy Change

During the test of an internal combustion engine,3.00 L of nitrogen gas at 18.5 degrees Celsius was compressed suddenly and irreversibly to 0.500 L by driving in a piston. in the process, the temperature of the gas increased to 28.1 degrees celsius. Assume ideal behavior. what is the change in entro...
Fri Jan 26, 2018 1:10 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Degeneracy
Replies: 3
Views: 188

### Degeneracy

In class we compared the equilibrium of entropy and the equilibrium in entropy, where in entropy equilibrium was hit at a minimum value while in entropy it was reached at a maximum value. My notes are incomplete and I was wondering what the point of this comparison was.
Fri Jan 19, 2018 12:09 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Internal Energy
Replies: 3
Views: 302

### Internal Energy

In class, we went over an example that talked about a piston moving out and the energy of the system decreasing by an amount. The first diagram showed the formula F=P*A and the second showed that V=A*d. Why is it that the volume is the area times displacement of the piston? Why does it only take int...
Wed Jan 17, 2018 11:27 pm
Forum: General Science Questions
Topic: Sig Figs
Replies: 3
Views: 482

### Sig Figs

Will we be docked points for incorrect significant figures on quizzes and exams?
Wed Jan 17, 2018 11:17 pm
Forum: Calculating Work of Expansion
Topic: 8.3 Homework
Replies: 4
Views: 343

### 8.3 Homework

Can someone explain why work on air is positive when an air bicycle pump is compressed .
I thought work is positive if work is done by the system, and negative if work is done on the system. Wouldn't work be done on air, so it'd be negative?
Sun Mar 05, 2017 10:24 pm
Topic: 4.26 Electron Movement
Replies: 1
Views: 599

### 4.26 Electron Movement

Complete the reaction mechanism.(Given an HI and CH2CH2 structure) Is there any way to tell how many steps it takes to complete a reaction mechanism? In this instance, one of the double bonds goes to the Hydrogen in HI and the single bond on HI goes to Iodine. From there, how do I determine what to ...
Sun Feb 26, 2017 8:55 pm
Forum: *Electrophiles
Topic: Problem 4.3 of HW
Replies: 1
Views: 298

### Problem 4.3 of HW

When drawing the structure of CH2F2 how do you determine what element is going to be represented by a wedged bond (black triangle looking bond) and a dashed line as opposed to solid lines? Does it matter what molecule in the structure is assigned these bonds? For example, rather than the hydrogens h...
Tue Feb 21, 2017 7:05 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Activation Energy
Replies: 4
Views: 624

### Activation Energy

Can someone explain why a reaction with very low activation energy has a rate that does not change much with temperature.
Sun Feb 05, 2017 10:52 pm
Forum: Balancing Redox Reactions
Topic: Oxidation States
Replies: 3
Views: 491

### Oxidation States

How do you determine which elements are undergoing changes in oxidation states?

Ex: H(+) + Cr2O7 (2-) + C2H5OH ----> Cr(3+) + C2H4O +H20

I know that Cr is one of the elements, but how is Carbon also undergoing changes?
Tue Jan 31, 2017 4:10 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Quiz 1 Preparation
Replies: 1
Views: 369

### Quiz 1 Preparation

#3 If 2 mols of an ideal gas at 300 degrees K and 3 atm expands isothermally and reversibly from 6 to 18 L and has a final pressure of 1.2 atm what is its w, q, and delta U? To find the work I used -n*R*T*ln(v2/v1) and plugged in the values as follows =-2*8.206 *300*ln(18/6) =5409.127 L*atm and to c...
Sun Jan 15, 2017 5:22 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Chapter 8 Number 19
Replies: 2
Views: 338

### Re: Chapter 8 Number 19

Ohh okay, Thank you :)
Sun Jan 15, 2017 5:12 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Chapter 8 Number 19
Replies: 2
Views: 338

### Chapter 8 Number 19

a)calculate the heat that must be supplied to a 500.0 g copper kettle containing 400.0 g of water to raise its temperature from 22.0 degrees Celsius to 100degrees celsius. I used the equation q=(m)*(Cs)*(delta T) and plugged in the given information as follows: (400g)*(4.184 J/C*g)*(100-22) and got ...
Mon Nov 16, 2015 11:02 pm
Forum: Naming
Topic: Coordination Compounds
Replies: 1
Views: 337

### Coordination Compounds

When naming coordination compounds how is it that we get the roman numeral after the cation name? How do we identify it?
For example if we are given [Co(NH3)5Cl]Cl. 2H20 the name for this compound is Penta Ammine Chloro Cobalt(II) Chloride dihydrate. How is it that we get (II) after cobalt?
Mon Nov 09, 2015 12:00 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating Equilibrium Composition
Replies: 1
Views: 225

### Calculating Equilibrium Composition

An example in the course reader asks to find K. It states: Mix .500 mol*L -1 N 2 with .800 mol*L -1 H 2 . Also given at equilibrium there's .150 mol*L -1 NH 3 . What's K. The balanced equation is 1 mole N 2 + 3 mole H 2 <--> 2 mole NH 3 The chart looks like this: N 2 H 2 NH 3 Initial Molar concentra...
Sun Nov 01, 2015 6:35 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Bond Order
Replies: 2
Views: 1660

### Bond Order

I know that if when computing the bond order we get
0:the molecule won't form
1: means a single bond
2: means a double bond
3: means a triple bond
but what happens when we get fractions of a number such as 2.5? What kind of bond is formed then?
Tue Oct 20, 2015 10:51 pm
Forum: Ionic & Covalent Bonds
Topic: 3.21 Ground state
Replies: 5
Views: 842

### 3.21 Ground state

Give the ground-state electron configuration and number of unpaired electrons expected for Ag+

I understand that the configuration is [Kr]4d10, but I don't understand why it's not Palladium which is also 4d10. They're both similar. Is either one correct or why is it not Palladium?
Sun Oct 11, 2015 10:17 am
Forum: Quantum Numbers and The H-Atom
Topic: Problem 2.23
Replies: 1
Views: 435

### Problem 2.23

For each orbital listed in 2.21 (6p, 3d, 2p, 5f), give the possible values of the magnetic quantum number.
Thu Oct 01, 2015 8:16 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals of chem: Dilution G9
Replies: 4
Views: 2008

### Fundamentals of chem: Dilution G9

The question states: A chemist studying the properties of photographic emulsions needed to prepare 500.0 mL of 0.179 M AgN03 (aq). What mass of Silver Nitrate must be placed into a 500.0-mL volumetric flask, dissolved, and diluted to the mark with water? I know I have to find the mass of AgNO3, but ...