## Search found 56 matches

Sat Mar 17, 2018 9:25 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Rate Constant [ENDORSED]
Replies: 2
Views: 221

### Re: Rate Constant[ENDORSED]

its the one that's the steepest
Sat Mar 17, 2018 9:21 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Water and Cell Diagrams
Replies: 3
Views: 234

### Re: Water and Cell Diagrams

no,If something is aqueous it is implied that there is water
Sat Mar 17, 2018 9:18 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Cell Potential of a Couple
Replies: 2
Views: 118

### Re: Standard Cell Potential of a Couple

you want E to be as positive as it can because positive standard potential means spontaneity
Sat Mar 17, 2018 9:17 pm
Forum: Calculating Work of Expansion
Topic: Work with changeP and constant V
Replies: 4
Views: 280

### Re: Work with changeP and constant V

if delta v is equal to zero then work is equal to zero by the equation w=-pdeltav
Wed Mar 07, 2018 3:25 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Unique rates
Replies: 4
Views: 203

### Re: Unique rates

And since there are assigned homework problems involving unique rates i assume it can be asked on the test
Wed Mar 07, 2018 3:19 pm
Forum: Administrative Questions and Class Announcements
Topic: practice final?
Replies: 4
Views: 315

### Re: practice final?

I'm sure some of the review sessions will have practice problems in preparation for the final
Wed Mar 07, 2018 3:12 pm
Forum: Second Order Reactions
Topic: 15.35
Replies: 1
Views: 278

### Re: 15.35

in Part A you are using the half life equation where in part b and c you use the formula: (1/[a]) = (1/[a]0) +kt and solve for t
Wed Feb 28, 2018 9:22 pm
Forum: General Rate Laws
Topic: Significance
Replies: 3
Views: 129

### Re: Significance

the order shows how the reactants effect the rate
Wed Feb 28, 2018 9:19 pm
Forum: Zero Order Reactions
Topic: Units of k [ENDORSED]
Replies: 13
Views: 367

### Re: Units of k[ENDORSED]

The units of k can change the units for rate when you are using it in a calculation
Wed Feb 28, 2018 9:13 pm
Forum: Zero Order Reactions
Topic: Negative order
Replies: 4
Views: 164

### Re: Negative order

i am unsure if the order can be negative, good question
Tue Feb 20, 2018 8:02 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.97-cathode vs anode
Replies: 2
Views: 79

### Re: 14.97-cathode vs anode

cathode is reduction (gaining electrons) and anode is oxidation (losing electrons )
Tue Feb 20, 2018 7:59 pm
Forum: Balancing Redox Reactions
Topic: Writing Half-Reactions
Replies: 6
Views: 251

### Re: Writing Half-Reactions

cathode is reduction and anode is oxidation
Tue Feb 20, 2018 7:54 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode/Cathode
Replies: 2
Views: 82

### Re: Anode/Cathode

RED CAT is another way to remember that reduction is cathode
Sun Feb 18, 2018 11:24 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation (log vs. ln)
Replies: 5
Views: 633

### Re: Nernst Equation (log vs. ln)

in class he mentioned log is included because that is what is used in the ph scale
Sun Feb 18, 2018 11:20 pm
Forum: Balancing Redox Reactions
Topic: 14.15
Replies: 2
Views: 96

### Re: 14.15

if you think it is an error it may be under Lavelle's solution manual mistakes on his website
Sun Feb 18, 2018 11:11 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7420
Views: 980096

### Re: Post All Chemistry Jokes Here

What did one ion say to the other?
I got my ion you
Sun Feb 18, 2018 11:07 pm
Forum: Balancing Redox Reactions
Topic: Exercise 14.17
Replies: 6
Views: 207

### Re: Exercise 14.17

to start the cell diagram it helps to label each side as anode or cathode
Sun Feb 11, 2018 11:43 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Homework Problem 9.69
Replies: 2
Views: 114

### Re: Homework Problem 9.69

you use the 2nd and 3rd equation to find delta G for three moles of NADH and then divide it by the first equation because the first equation represents NADH per mole of ATP
Sun Feb 11, 2018 11:39 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 9.81
Replies: 2
Views: 106

### Re: 9.81

I was also wondering how you know to set up the equation in this manner
Sun Feb 11, 2018 11:37 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: 9.47
Replies: 1
Views: 120

### Re: 9.47

the total entropy change is equal to zero not just entropy of the system or surroundings
Wed Jan 31, 2018 8:42 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: The value of Cp
Replies: 8
Views: 314

### Re: The value of Cp

on the test we should be given the value of Cp and you only use Cp if it explicitly says constants pressure.
Wed Jan 31, 2018 8:38 pm
Forum: Calculating Work of Expansion
Topic: Work Equations [ENDORSED]
Replies: 9
Views: 354

### Work Equations[ENDORSED]

How do you know whether to use the work equation -p deltaV or -nRTln(v2/V1)?
Wed Jan 31, 2018 8:30 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 9.57
Replies: 1
Views: 81

### 9.57

Why does the solution to chapter 9 question 57 use h20 (aq) when the problem gives it as h20 (l) and i don't believe h20 aq exists?
Wed Jan 24, 2018 10:08 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Changing the energy of a system
Replies: 6
Views: 231

### Re: Changing the energy of a system

You can also change the energy of a system by heating or cooling it( if its a closed system) and by doing work on the system (compressing a piston)
Wed Jan 24, 2018 3:13 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Positive and Negative Signs 8.21
Replies: 3
Views: 143

### Re: Positive and Negative Signs 8.21

it doesn't matter which side has the negative. either way it would turn out to be the same answer
Tue Jan 23, 2018 8:11 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 8.21
Replies: 1
Views: 70

### 8.21

in question 8.21 what does the term negligible mean in regards to the concept of the question ?
Thu Jan 18, 2018 10:08 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Is there a way specific way to approach into seeing if open closed or isolated?
Replies: 9
Views: 316

### Re: Is there a way specific way to approach into seeing if open closed or isolated?

for example a pot on the oven with no lid is open, a pot on the oven with a lid is closed, and a really good thermal cup wouldn't allow for the transfer of energy or matter so it would be isolated
Thu Jan 18, 2018 10:02 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Question 8.43
Replies: 2
Views: 100

### Re: Question 8.43

by looking at the enthalpies you can see that the melting should happen twice as fast as vaporization which is one indication as to why the answer is c
Thu Jan 18, 2018 9:58 pm
Forum: Calculating Work of Expansion
Topic: Work for compression/expansion
Replies: 2
Views: 99

### Re: Work for compression/expansion

The negative indicates that the system is losing energy
Wed Jan 17, 2018 8:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.45
Replies: 2
Views: 67

### 8.45

Why in the solutions manual does it say that the reaction enthalpy is 358.8 kj. mol^-1 versus in the question it is simply written as 358.8 kj ?
Thu Jan 11, 2018 8:05 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 2
Views: 85

### Re: Bond Enthalpies

it is the enthalpy change when a bond is broken. where enthalpy is the state function that allows us to keep track of energy changes at constant pressure
Thu Jan 11, 2018 7:55 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.31 b)
Replies: 2
Views: 89

### Re: 8.31 b)

Can someone also please explain where the 12.5 J/mol c comes from ?
Thu Jan 11, 2018 7:38 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.31 b)
Replies: 2
Views: 89

### 8.31 b)

in question 8.31 part b what does the equation Cvm = (3/2)R represent ?
Sat Dec 09, 2017 11:13 pm
Forum: Trends in The Periodic Table
Replies: 2
Views: 148

ionic radius are different because cations are smaller than their parents while anions are larger than their parents so you cant look at ionic radius as you do atomic radius. I hope this helps
Sat Dec 09, 2017 2:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: t-shaped
Replies: 4
Views: 273

### Re: t-shaped

Thank you for the help
Sat Dec 09, 2017 2:20 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Henderson Hassleback [ENDORSED]
Replies: 1
Views: 114

### Henderson Hassleback[ENDORSED]

Should we know the Henderson hassleback formula for the final ?
Fri Dec 08, 2017 3:21 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted vs. Lewis
Replies: 4
Views: 230

### Re: Bronsted vs. Lewis

for bronsted most of a strong acid is depronated in solution and for a weak acid only a small fraction are
Fri Dec 08, 2017 3:09 pm
Forum: Lewis Structures
Topic: Octet vs Formal Charge
Replies: 2
Views: 166

### Re: Octet vs Formal Charge

some elements have to follow the octet rule, and you need to make sure that the formal charge adds up to the total charge
Mon Nov 27, 2017 11:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: t-shaped
Replies: 4
Views: 273

### t-shaped

What are the bond angles for something that is t-shaped?
Sun Nov 26, 2017 7:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.11
Replies: 1
Views: 125

### 4.11

Can someone please explain to me why part a of number 11(sulfur tetrachloride) in chapter 4 is trigonal bipyramidal instead of seesaw?
Mon Nov 20, 2017 9:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: seesaw
Replies: 2
Views: 121

### seesaw

Why is the lone pair an equatorial instead of axial in a seesaw shape?
Mon Nov 20, 2017 9:19 pm
Forum: Hybridization
Topic: lone pair effect on hybridization
Replies: 3
Views: 162

### lone pair effect on hybridization

How do lone pairs effect the calculation of hybridization?
Mon Nov 20, 2017 8:55 pm
Forum: Hybridization
Topic: Writing Hybridization
Replies: 3
Views: 164

### Re: Writing Hybridization

In the solution manual it is written with d at the end.
Thu Nov 16, 2017 8:03 pm
Forum: Determining Molecular Shape (VSEPR)
Replies: 4
Views: 193

A radical is electrons with unpaired spins. I assume you must first evaluate all the elements of the compound. For example on the midterm it would not make sense to put the one electron on oxygen or hydrogen because their octets are already full, leaving the electron to be put on carbon.
Sun Nov 05, 2017 7:47 pm
Forum: Lewis Structures
Topic: 11/5 ch3 review
Replies: 2
Views: 167

### 11/5 ch3 review

In the review session one of the examples was [HC2O4]^-1
I do not understand why the h atom attaches to an O atom instead of the C. Could someone please explain why ?
Sun Nov 05, 2017 7:44 pm
Forum: Lewis Structures
Topic: 11/5 ch3 review SNF3
Replies: 1
Views: 129

### 11/5 ch3 review SNF3

Why is S in the middle of the lewis structure?
Sun Nov 05, 2017 7:41 pm
Forum: Lewis Structures
Topic: Review Session ClO4-
Replies: 2
Views: 128

### Re: Review Session ClO4-

you need to consider the formal charge to make the molecule more stable
Sun Nov 05, 2017 7:30 pm
Forum: Lewis Structures
Topic: Expanded Octet Rule
Replies: 3
Views: 181

### Re: Expanded Octet Rule

Phosphorus is a bigger size and has an empty d-orbital
Sun Oct 29, 2017 9:26 pm
Forum: Trends in The Periodic Table
Topic: f-orbitals
Replies: 6
Views: 1223

### Re: f-orbitals

also how would you get the electron configuration for Th(thorium) would it include an f-orbital or just (Rn) 7s^26d^2 ?
Sun Oct 29, 2017 9:06 pm
Forum: Trends in The Periodic Table
Topic: 2.97
Replies: 2
Views: 261

### Re: 2.97

You would start by using the Rydberg equation: E=Z^2hR(1/n^2lower- 1/n^2 upper)
Fri Oct 20, 2017 12:29 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Configuration Notation [ENDORSED]
Replies: 5
Views: 245

### Re: Configuration Notation[ENDORSED]

if you just write 2p2 it does not specify what the ml quantum number would be. So you would need to include (for example: 2px1, 2py1)
Fri Oct 20, 2017 12:10 pm
Forum: Properties of Electrons
Topic: Energy Levels
Replies: 3
Views: 240

### Re: Energy Levels

It depends on the energy of the incoming photon
Thu Oct 12, 2017 10:01 pm
Forum: Properties of Electrons
Topic: Series
Replies: 6
Views: 419

### Re: Series

I was also told that you should know that the Balmer series corresponds with visible light and that the Lyman series corresponds to ultraviolet
Thu Oct 12, 2017 9:55 pm
Forum: Properties of Light
Topic: Homework 1.23
Replies: 2
Views: 112

### Re: Homework 1.23

I believe the conversion will be given, but the conversion is 1ev=1.602x10^-19J and in problem 23 you would have to first convert it from Kev to ev.
Thu Oct 05, 2017 7:44 pm
Forum: Molarity, Solutions, Dilutions
Topic: Homework Problem G23
Replies: 2
Views: 412

### Re: Homework Problem G23

You would start by using the 0.50g of NaCl given and divide it by the molar mass of NaCl (58.44g mol^-1) and then multiply that by the ratio of moles of NaCl to Cl ions which is 1:1. And then you would add that to the concentration in KCl by starting with the given (0.30g KCl) and dividing that by t...
Thu Oct 05, 2017 7:08 pm
Forum: Balancing Chemical Reactions
Topic: H1 // Book Problem [ENDORSED]
Replies: 7
Views: 396

### Re: H1 // Book Problem[ENDORSED]

Yes, because by the law of conservation of mass, matter can not be created nor destroyed