Search found 62 matches
- Sat Mar 17, 2018 10:19 pm
- Forum: First Order Reactions
- Topic: HW #15.37c
- Replies: 2
- Views: 448
Re: HW #15.37c
I had a similar question. but I noticed that when using this form of the first-order rate law, the solutions were consistent with leaving out the volume.
- Sat Mar 17, 2018 10:18 pm
- Forum: Second Order Reactions
- Topic: 15.35
- Replies: 6
- Views: 1056
Re: 15.35
Use the half-life equation for the second-order reaction. then substitute A for the fraction of A naught.
- Sat Mar 17, 2018 10:17 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: 15.51
- Replies: 2
- Views: 489
Re: 15.51
would the unique rate for the formation of NOBr have a coefficient of 2?
Re: Final
just to the extent that he covered during lecture.
- Fri Mar 16, 2018 3:42 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Question 15.51
- Replies: 8
- Views: 978
Re: Question 15.51
The slow step determines the rate of the reaction so that is where you get your rate law from.
- Fri Mar 16, 2018 3:40 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: The Effect of Temperature
- Replies: 3
- Views: 423
Re: The Effect of Temperature
raising temp will increase the rate constant and the speed of the reaction.
- Fri Mar 16, 2018 3:39 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: 15.67
- Replies: 3
- Views: 496
Re: 15.67
It all comes down to using two sets of the Arrehenius equation and creating a ratio out of the two.
- Mon Mar 12, 2018 10:21 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: How does a homogeneous catalyst affect (a) the rate law; (b) the equilibrium constant? [ENDORSED]
- Replies: 5
- Views: 1118
Re: How does a homogeneous catalyst affect (a) the rate law; (b) the equilibrium constant? [ENDORSED]
I believe it decreases the activation energy which will in turn increase the rate constant and rate of the reaction.
- Mon Mar 12, 2018 10:19 pm
- Forum: Zero Order Reactions
- Topic: Half Lives? [ENDORSED]
- Replies: 7
- Views: 1159
Re: Half Lives? [ENDORSED]
Yes, half-life works for that fraction.
- Mon Mar 12, 2018 10:18 pm
- Forum: First Order Reactions
- Topic: Reaction Order [ENDORSED]
- Replies: 6
- Views: 961
Re: Reaction Order [ENDORSED]
Reaction order would be the exponent for the concentration in the rate law.
- Mon Mar 12, 2018 4:08 pm
- Forum: Second Order Reactions
- Topic: Half life
- Replies: 6
- Views: 936
Re: Half life
Since it is a fraction, the value would appear flipped when it is used in the second-order reaction. take a look at the respective equations and you will see that the values correspond to each other.
- Fri Mar 09, 2018 8:45 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: 15.65 c
- Replies: 2
- Views: 429
15.65 c
Why should k increase more than the k of the reverse reaction?
- Fri Mar 09, 2018 8:29 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: 15.63
- Replies: 3
- Views: 399
Re: 15.63
what should be the final answer?
- Fri Mar 02, 2018 10:28 am
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Hw 15.1 [ENDORSED]
- Replies: 7
- Views: 1056
Re: Hw 15.1 [ENDORSED]
yes due to the ratio.
- Fri Mar 02, 2018 10:27 am
- Forum: General Rate Laws
- Topic: Unique Rate [ENDORSED]
- Replies: 5
- Views: 803
Re: Unique Rate [ENDORSED]
Its important to note that everything in the reaction should have the same unique rate.
- Fri Mar 02, 2018 10:26 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: 15.23 & 15.29 [ENDORSED]
- Replies: 2
- Views: 474
Re: 15.23 & 15.29 [ENDORSED]
I believe that in order to produce B, A has to be used up. Therefore, B uses x amount A so we subtract A initial minus x.
- Sun Feb 25, 2018 11:46 pm
- Forum: General Rate Laws
- Topic: Rate of Reaction
- Replies: 4
- Views: 542
Re: Rate of Reaction
The 2 is there due to the ratio of the coefficients between the reactants and the products.
- Sun Feb 25, 2018 11:45 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: activation energy
- Replies: 4
- Views: 549
Re: activation energy
Generally, a higher activation energy will require more energy input, which will lead to a relatively slower reaction.
- Sun Feb 25, 2018 11:44 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: unique average rates
- Replies: 3
- Views: 676
Re: unique average rates
Aren't the unique average rates positive for both products and reactants?
- Mon Feb 19, 2018 10:37 pm
- Forum: Balancing Redox Reactions
- Topic: 14.9
- Replies: 2
- Views: 410
Re: 14.9
don't you also have to check with the half reaction of iodine in this case too?
- Mon Feb 19, 2018 2:35 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 14.47b
- Replies: 1
- Views: 351
14.47b
For the anode, there is no water. Where did the water come from based on the solution manual?
- Sun Feb 18, 2018 9:56 am
- Forum: Balancing Redox Reactions
- Topic: Half reaction
- Replies: 1
- Views: 281
Half reaction
When given this following pair, I3-/I-, the half-reaction is I3- +2 e- --> 3 I-.
How did this half-reaction come about? I was unsure about how to find the number of electrons in this case when the charge is both negative one on each side.
How did this half-reaction come about? I was unsure about how to find the number of electrons in this case when the charge is both negative one on each side.
- Fri Feb 16, 2018 9:17 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 14.9
- Replies: 1
- Views: 263
14.9
When calculating these problems, how do we figure out n, the number of moles of electrons?
- Mon Feb 12, 2018 12:12 am
- Forum: Van't Hoff Equation
- Topic: Derivation
- Replies: 9
- Views: 1211
Re: Derivation
I believe you should understand that this equation comes from the two Gibbs free energy equations that we have learned.
- Sat Feb 10, 2018 3:19 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: 9.35 [ENDORSED]
- Replies: 2
- Views: 435
Re: 9.35 [ENDORSED]
Can you explain the differing Cv values for each of the gases in the solution manual corrections?
- Sat Feb 10, 2018 3:14 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 9.35 [ENDORSED]
- Replies: 5
- Views: 637
Re: 9.35 [ENDORSED]
I believe this problem's solution is on the solution manual errors. A and C should have the same amount of disorder.
- Wed Feb 07, 2018 10:52 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 9.65
- Replies: 6
- Views: 751
Re: 9.65
Would a spontaneous reaction (negative free energy) be more stable?
- Sun Feb 04, 2018 8:21 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Van't Hoff's Equation [ENDORSED]
- Replies: 3
- Views: 559
Re: Van't Hoff's Equation [ENDORSED]
It allows us to calculate K at a different temperature if the standard enthalpy of reaction is known.
- Sun Feb 04, 2018 7:58 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Reversible an Irreversible [ENDORSED]
- Replies: 4
- Views: 776
Re: Reversible an Irreversible [ENDORSED]
In edition to a reversible reaction being more efficient (more useful work done), a reversible has a constant Temperature and Volume and Pressure are inversely related.
An irreversible pathway has a changing temperature and work is done against a constant external pressure.
An irreversible pathway has a changing temperature and work is done against a constant external pressure.
- Sun Feb 04, 2018 7:54 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Reversible systems
- Replies: 7
- Views: 873
Re: Reversible systems
You would find the entropy change for both change in pressure and volume and add the net change for this reaction.
- Sun Feb 04, 2018 7:51 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Second Law of Thermodynamics [ENDORSED]
- Replies: 5
- Views: 964
Re: Second Law of Thermodynamics [ENDORSED]
Entropy can still increase in these instances.
For instance, even when the entropy of an anabolic reaction decreases, there is still heat released to the surroundings, thus increasing the entropy change.
For instance, even when the entropy of an anabolic reaction decreases, there is still heat released to the surroundings, thus increasing the entropy change.
- Sat Jan 27, 2018 9:22 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: Finding W
- Replies: 3
- Views: 425
Re: Finding W
If there are two states for one particle, degeneracy is 2^1.
For N particles in one of two states, degeneracy (w) = 2^N
For N particles in one of two states, degeneracy (w) = 2^N
- Sat Jan 27, 2018 9:19 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 9.7 and 9.11 formula differences
- Replies: 4
- Views: 554
Re: 9.7 and 9.11 formula differences
In the first question, we use the first formula because it is asking for entropy at a constant pressure. when you derive the equation, it comes out as that. For the second problem, the conditions are different because it is isothermal. Thus, you end up using a different equation that keeps into acco...
- Sat Jan 27, 2018 9:13 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Units for Entropy
- Replies: 4
- Views: 462
Re: Units for Entropy
It depends on the question, whether it is asking entropy per mole or not.
- Sat Jan 20, 2018 8:28 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Ch 8 #53 Part b
- Replies: 8
- Views: 1897
Re: Ch 8 #53 Part b
Hi RenuChepuru1L, The heat of the reaction is equal to the negative heat of the calorimeter because the calorimeter is gaining heat from the reaction. Hence to calculate heat gained by the calorimeter, we use C(delta T). The question asks for the internal energy change for the reaction of 1.00 mol ...
- Thu Jan 18, 2018 3:43 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 8.23
- Replies: 5
- Views: 603
Re: 8.23
I had the same question. But I think as long as we are consistent throughout the problem, either options work.
- Thu Jan 18, 2018 3:41 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 8.67b
- Replies: 1
- Views: 181
8.67b
In 8.67 b, where do we find that the value to atomize one mol of C equals 717 kJ/mol?
- Thu Jan 18, 2018 3:35 pm
- Forum: Phase Changes & Related Calculations
- Topic: Heat Capacity
- Replies: 6
- Views: 742
Heat Capacity
For heat capacity/specific heat, do we use kJ or J? Or does it really matter, as long as we stay consistent?
- Sat Jan 13, 2018 2:27 pm
- Forum: Phase Changes & Related Calculations
- Topic: Intensive vs. Extensive
- Replies: 4
- Views: 422
Re: Intensive vs. Extensive
An extensive property is dependent on the amount of a substance.
We get an intensive property when we divide heat capacity by the amount of substance present.
We use extensive and intensive properties when dealing with specific heat capacities.
We get an intensive property when we divide heat capacity by the amount of substance present.
We use extensive and intensive properties when dealing with specific heat capacities.
- Sat Jan 13, 2018 2:24 pm
- Forum: Phase Changes & Related Calculations
- Topic: Boiling water vs. steam
- Replies: 6
- Views: 1071
Re: Boiling water vs. steam
If you look at the heating graph, the enthalpy of vaporization is a longer line than the enthalpy of fusion. This shows that there is a greater amount of heat given off by the steam during its phase change.
- Sat Jan 13, 2018 2:21 pm
- Forum: Phase Changes & Related Calculations
- Topic: Standard Reaction Enthalpy
- Replies: 8
- Views: 780
Re: Standard Reaction Enthalpy
Standard reaction enthalpy is the reaction enthalpy when all R and P are in their standard state at 1 ATM.
Standard enthalpy of formation is the standard reaction enthalpy for the formation of one mole of a substance from its elements in their most stable form.
Standard enthalpy of formation is the standard reaction enthalpy for the formation of one mole of a substance from its elements in their most stable form.
- Sat Dec 09, 2017 8:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Practice Test Fall 2017 [ENDORSED]
- Replies: 19
- Views: 3371
Re: Practice Test Fall 2017 [ENDORSED]
for Week 9, problem 6c, why does expansion favor products?
- Sat Dec 09, 2017 7:09 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 12.23 [ENDORSED]
- Replies: 7
- Views: 1195
Re: 12.23 [ENDORSED]
So does the Equilibrium constant still equal 10^-14 even if the temperature does not equal 25 degrees?
- Fri Dec 08, 2017 9:49 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: Oxides
- Replies: 1
- Views: 527
Oxides
How do you know if a metal oxide produces a strong base?
How do you know if a non-metal oxide produces either a strong or weak base?
How do you know if a non-metal oxide produces either a strong or weak base?
- Sun Dec 03, 2017 9:16 pm
- Forum: Lewis Acids & Bases
- Topic: 12.13
- Replies: 2
- Views: 367
12.13
a. Is NH3 a Lewis base because it wants to donate the lone pair?
b. Is BF3 a Lewis acid because it wants to accept an electron pair to form a full octet?
c. Why does Ag+ (a Lewis acid) want to gain an electron pair?
b. Is BF3 a Lewis acid because it wants to accept an electron pair to form a full octet?
c. Why does Ag+ (a Lewis acid) want to gain an electron pair?
- Sun Dec 03, 2017 8:11 pm
- Forum: Conjugate Acids & Bases
- Topic: HW: 12.9
- Replies: 2
- Views: 892
Re: HW: 12.9
For part c, why is there no proton transferred when CH3COOH gains a hydrogen to become CH3CONH2?
- Sun Nov 26, 2017 9:38 pm
- Forum: Naming
- Topic: Polydentate
- Replies: 3
- Views: 454
Re: Polydentate
Polydentates have multiple bonding sites. CO3^2 has multiple spots because the lone pairs of its oxygen allows for different bonding spots.
- Fri Nov 24, 2017 4:20 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Homework question 17.33
- Replies: 4
- Views: 429
Re: Homework question 17.33
If the atoms have a formal charge of 0, it will not want to bind with anything, correct?
17.31 d
This problem says to write out the formula of sodium bisoxalato(diaqua)ferrate(III).
How come oxalato in the answer is written after aqua?
It goes (OH2)2 (C2O4)?
When they tell us to write out the formula alphabetically, are we using the name or the symbols for alphabetical order?
How come oxalato in the answer is written after aqua?
It goes (OH2)2 (C2O4)?
When they tell us to write out the formula alphabetically, are we using the name or the symbols for alphabetical order?
- Sun Nov 19, 2017 11:31 pm
- Forum: Hybridization
- Topic: Pi Bonds
- Replies: 3
- Views: 617
Re: Pi Bonds
A double bond needs both a pi bond and sigma bond. When two atoms are bound by more than one covalent bond, the additional orbitals overlap side by side to form pi bonds.
- Sun Nov 19, 2017 11:28 pm
- Forum: Hybridization
- Topic: Pi Bonds
- Replies: 2
- Views: 426
Re: Pi Bonds
It's based on the structure of the bonds. When we look at how the pi bonds are connected, there is no room for rotation without the bonds disconnecting. But when we look at sigma bonds, their cylindrical interaction allows rotation.
- Sun Nov 12, 2017 11:17 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 4.1
- Replies: 5
- Views: 563
Re: 4.1
Lone pairs are the reasons for the bond angles being closer together. We learned in class that the lone-lone pair repulsion strength is the greatest, followed by the lone-bonding pairs. We know that bonding pairs want to be as far apart as possible. Thus, the explanation for the bond angles being cl...
- Sun Nov 12, 2017 11:12 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Notation
- Replies: 3
- Views: 580
Re: VSEPR Notation
With VSEPR Models, molecules can have the same amount of electron densities. The difference in these molecules can lie in the angles between the bonds. For instance, trigonal pyramidals have different bond angles. Sulfite have O-S-O bond angles of 106 degrees while NH3 has H-N-H bond angles that are...
- Sun Nov 05, 2017 10:40 pm
- Forum: Ionic & Covalent Bonds
- Topic: 3.25
- Replies: 6
- Views: 783
Re: 3.25
With these two charges, find the lowest common factor between the two. Use this lowest common factor as the subscript for the opposite charges.
- Sun Nov 05, 2017 10:37 pm
- Forum: SI Units, Unit Conversions
- Topic: Si Unit for molar mass
- Replies: 3
- Views: 2111
Si Unit for molar mass
For problems with molar mass, should we stick with grams always even if the SI unit is kilograms?
- Sun Oct 29, 2017 10:40 am
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy [ENDORSED]
- Replies: 2
- Views: 559
Ionization Energy [ENDORSED]
Why does Oxygen go against the trend of having an increasing ionization energy to the right of the periodic table?
- Mon Oct 23, 2017 1:18 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 2.1a
- Replies: 1
- Views: 206
2.1a
Why does the energy of a electron increase from a 1s to a 2p orbital?
- Sat Oct 21, 2017 5:27 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 3d And 4s Orbital Energy Levels [ENDORSED]
- Replies: 3
- Views: 1506
Re: 3d And 4s Orbital Energy Levels [ENDORSED]
Under certain circumstances is the 3d state lower in energy.
Once the 4s state is occupied and the electron enters the 3d state, then the 3d state is lower in energy than 4s. If the electron hasn't reached 3d yet, then 4s is written first.
Once the 4s state is occupied and the electron enters the 3d state, then the 3d state is lower in energy than 4s. If the electron hasn't reached 3d yet, then 4s is written first.
- Sat Oct 21, 2017 5:23 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 3d and 4s
- Replies: 3
- Views: 330
Re: 3d and 4s
I think after the 4s state/orbital is occupied and the electron enters the 3d state, then the 3d state is lower in energy than 4s.
- Sat Oct 14, 2017 1:05 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Change in energy of an electron [ENDORSED]
- Replies: 3
- Views: 416
Change in energy of an electron [ENDORSED]
Hi, I have two questions: 1. when we are finding the change in energy using the equations, are we finding the change in energy of only the electron? Will the change in energy be either positive or negative based on if the electron is absorbing or emitting? 2. When an electron emits a photon, will th...
- Tue Oct 03, 2017 10:22 pm
- Forum: Significant Figures
- Topic: All students read this sig fig post [ENDORSED]
- Replies: 170
- Views: 33492
Re: All students read this sig fig post [ENDORSED]
when finding the molar mass in the periodic table, how many sig figs do we use?
- Tue Oct 03, 2017 10:20 pm
- Forum: Significant Figures
- Topic: All students read this sig fig post [ENDORSED]
- Replies: 170
- Views: 33492
Re: All students read this sig fig post [ENDORSED]
Hi, when there are numerous instances in a problem when multiplication/division is needed, can we just find the final answer and do the sig fig in the end after all the multiplication? Also, is a problem with both addition and multiplication different because you have to recount the sig figs after y...