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: 559
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: 727
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: 409
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: 681
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: 660
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: 654
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: 509
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: 502
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: 1456
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: 812
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: 268
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: 890
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: 320
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: 6469
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: 364
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: 9651
- Views: 2970107
Re: Post All Chemistry Jokes Here
What did one ion say to the other?
I got my ion you
I got my ion you
- Sun Feb 18, 2018 11:07 pm
- Forum: Balancing Redox Reactions
- Topic: Exercise 14.17
- Replies: 6
- Views: 757
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: 375
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: 369
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: 322
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: 1504
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: 1383
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: 280
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: 683
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: 415
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: 222
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: 830
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: 369
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: 290
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: 192
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: 165
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: 289
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: 289
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
- Topic: Isoelectronic Ionic Radius
- Replies: 2
- Views: 415
Re: Isoelectronic Ionic Radius
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: 577
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: 243
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: 578
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: 458
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: 577
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: 231
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: 324
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: 313
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: 562
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)
- Topic: Radicals
- Replies: 4
- Views: 609
Re: Radicals
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: 355
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 ?
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: 355
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: 366
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: 485
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: 6689
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: 487
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: 683
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: 581
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: 827
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: 197
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: 1208
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: 939
Re: H1 // Book Problem [ENDORSED]
Yes, because by the law of conservation of mass, matter can not be created nor destroyed