Search found 60 matches

by Nickolas Manipud 1C
Sun Mar 18, 2018 3:46 pm
Forum: Student Social/Study Group
Topic: Final
Replies: 11
Views: 980

Re: Final

I'm guessing they gave us cell potential to plug into our function and check our answer.
by Nickolas Manipud 1C
Sat Mar 17, 2018 2:47 pm
Forum: General Rate Laws
Topic: 15.49
Replies: 2
Views: 263

Re: 15.49

For those questions, you don't have to worry about the order. Just write the reactants into the rate law.
by Nickolas Manipud 1C
Fri Mar 16, 2018 10:20 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: What are the units of activation energy?
Replies: 2
Views: 401

Re: What are the units of activation energy?

You use J/mol.

Look at the Arrhenius equation, k = A*e^(-Ea/RT). R has units of J*K-1*mol-1 while T has units of K. The K will cancel out so what you have left is J*mol-1. You want to cancel both of these out which can be done with Ea with units of J*mol-1.
by Nickolas Manipud 1C
Thu Mar 15, 2018 5:30 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: H2 Cell Potential
Replies: 1
Views: 89

H2 Cell Potential

The book says that 2H+ + 2e- ---> H2 has a standard cell potential of "0, by definition." Why is this so?
by Nickolas Manipud 1C
Thu Mar 15, 2018 12:58 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.101b
Replies: 3
Views: 145

15.101b

How can OH- be a part of the rate law if it is an intermediate?
by Nickolas Manipud 1C
Wed Mar 14, 2018 10:17 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: HW#15.87
Replies: 2
Views: 128

Re: HW#15.87

How do we know that ii) at high sucrose concentration is first order?
by Nickolas Manipud 1C
Mon Mar 05, 2018 12:09 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: k'
Replies: 4
Views: 141

k'

Is there any relation between the pseudo-constant k' and the reverse rate constant k' ?
by Nickolas Manipud 1C
Sun Mar 04, 2018 7:11 pm
Forum: First Order Reactions
Topic: 15.25
Replies: 4
Views: 229

Re: 15.25

The above poster is right. It's a shortcut but you can still use the 1st order integrated rate law to solve the problem.
by Nickolas Manipud 1C
Sun Mar 04, 2018 7:08 pm
Forum: General Rate Laws
Topic: Knowing rate law equations
Replies: 5
Views: 239

Re: Knowing rate law equations

It's a good idea to know the derivations so you know where these equations come from which will give you a better understanding of the concepts.
by Nickolas Manipud 1C
Sun Mar 04, 2018 7:04 pm
Forum: First Order Reactions
Topic: Units in 15.29
Replies: 2
Views: 151

Re: Units in 15.29

It might have been because the question gives you minutes. You're right to say that it is usually standard to use seconds. On the test, I'm sure that you'll still get credit if you use either seconds or minutes unless the question wants a specfic unit.
by Nickolas Manipud 1C
Mon Feb 19, 2018 10:14 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Inert conductor
Replies: 2
Views: 96

Re: Inert conductor

You include it when a half-cell does not have any other solid or liquid that is part of the half-reaction to conduct electricity.
by Nickolas Manipud 1C
Mon Feb 19, 2018 10:10 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Working Cells
Replies: 1
Views: 117

Re: Working Cells

The delta G is the maximum cell potential (the potential before we connect the electrical current). When we connect the current, the delta G of the cell gets closer and closer to zero over time since the cell is going towards equilibrium. Therefore, since delta G and E are directly related, E will g...
by Nickolas Manipud 1C
Mon Feb 19, 2018 7:53 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.15
Replies: 1
Views: 135

Re: 14.15

I'm pretty sure you only put a comman if they are both aqueous and therefore in the same solution
by Nickolas Manipud 1C
Tue Feb 13, 2018 1:45 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Change in temp vs Change in volume equations
Replies: 2
Views: 117

Change in temp vs Change in volume equations

For these equations, , why is there a C for one equation and an R for the other
by Nickolas Manipud 1C
Mon Feb 12, 2018 5:13 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.43 HW
Replies: 3
Views: 278

Re: 9.43 HW

You usually want entropy to be in J/K so you would use molar heat capacity
by Nickolas Manipud 1C
Mon Feb 12, 2018 5:08 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: enthalpy vs standard
Replies: 2
Views: 130

Re: enthalpy vs standard

Standard enthalpy is the change in enthalpy for one mole under the conditions of 1 atm and 298 K.
by Nickolas Manipud 1C
Sun Feb 11, 2018 11:55 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy of Spontaneous Processes
Replies: 2
Views: 121

Re: Entropy of Spontaneous Processes

You can think of a process being spontaneous as the same as it being favorable. A process will naturally go in the direction that is favorable. In other words, it goes in the direction that increases entropy of the universe (this is true because of the 2nd law of thermodynamics).
by Nickolas Manipud 1C
Sun Feb 11, 2018 11:47 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: delta H
Replies: 4
Views: 147

Re: delta H

Molecules want to achieve a low energy state so they do this by releasing energy through the formation of bonds
by Nickolas Manipud 1C
Sun Feb 11, 2018 10:11 pm
Forum: Balancing Redox Reactions
Topic: Oxidation
Replies: 5
Views: 282

Re: Oxidation

The oxidation number is the charge of an atom or molecule.

If it loses, for example, three electrons, the oxidation number becomes 3+. If it gains 3 electrons, the oxidation number becomes 3-.
by Nickolas Manipud 1C
Sun Feb 11, 2018 10:08 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: delta S total
Replies: 2
Views: 141

Re: delta S total

The 2nd law states that the entropy of the universe is always increasing
by Nickolas Manipud 1C
Sun Feb 11, 2018 9:57 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Units of S and H
Replies: 4
Views: 400

Re: Units of S and H

Because you just found the standard enthaply or molar entropy of 1 mole of some substance from the chemical reaction
by Nickolas Manipud 1C
Sun Feb 11, 2018 9:47 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Gas Constant, R
Replies: 6
Views: 254

Re: Gas Constant, R

Some problems from the homework required using 8.206 x 10^-2
by Nickolas Manipud 1C
Sat Feb 10, 2018 3:44 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Work
Replies: 6
Views: 462

Re: Work

No. Free expansion occurs since there is no external pressure acting upon the system.
by Nickolas Manipud 1C
Mon Jan 22, 2018 10:49 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 8.91
Replies: 1
Views: 101

Re: 8.91

Wassup Janine You want to find how long it takes for ice to melt. The question says ice takes 10.5 h to reach 5 degrees Celsius and that the water at a liquid state at 0 degrees Celsius takes 0.5 h to reach 5 degrees Celsius. Therefore, the remaining 10.0 h must be from the ice melting. (10.5 - 0.5 ...
by Nickolas Manipud 1C
Mon Jan 22, 2018 8:54 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Problem 8.99
Replies: 6
Views: 259

Re: Problem 8.99

The limiting reactant determines the amount of energy released by the reaction which will help us determine the final temperature
by Nickolas Manipud 1C
Mon Jan 22, 2018 8:52 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.99
Replies: 6
Views: 208

Re: 8.99

You would use the enthalpies of formation for Zn+, Cl-, Zn (solid), and H+
by Nickolas Manipud 1C
Mon Jan 22, 2018 12:32 am
Forum: Administrative Questions and Class Announcements
Topic: Reversible and Isothermal Expansions
Replies: 2
Views: 197

Re: Reversible and Isothermal Expansions

Nope! This was taken from his website: "Test 1 covers only Chapter 8 material covered in Weeks 1 and 2. Week 3 I will cover equation 4 (page 266) in Chapter 8. Therefore, no questions on isothermal, reversible expansion on Test 1. Concept questions involving work and internal energy will be on ...
by Nickolas Manipud 1C
Mon Jan 22, 2018 12:29 am
Forum: Administrative Questions and Class Announcements
Topic: Week 3 Test Topic is endorsed
Replies: 37
Views: 1924

Re: Week 3 Test Topic is endorsed

Doing ALL the problems (except for the ones he said to skip) he assigns will prepare you enough for the test
by Nickolas Manipud 1C
Mon Jan 22, 2018 12:27 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: heat capacity
Replies: 2
Views: 110

Re: heat capacity

Molar = J/(mol*K)
Specific = J/(g*K)
Essentially, use molar heat capacity when dealing with moles and specific heat capacity when dealing with grams.
by Nickolas Manipud 1C
Sun Jan 14, 2018 2:21 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Quiz 1 [ENDORSED]
Replies: 2
Views: 226

Re: Quiz 1 [ENDORSED]

Depends on how much stuff we cover by Friday
by Nickolas Manipud 1C
Sun Jan 14, 2018 12:53 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Question about Question 8.7
Replies: 3
Views: 215

Re: Question about Question 8.7

Work is done ON a system when the system's internal energy increases. This makes sense if you think about a system being compressed (which is work being done ON the system). Since it's being compressed, more pressure is created, leading to more internal energy in that system.
by Nickolas Manipud 1C
Fri Jan 12, 2018 8:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Δ H=q
Replies: 3
Views: 213

Re: Δ H=q

You can use Dr. Lavelle's analogy of a person climbing a mountain. The change in altitude is a state function but the actual distance traveled is not a state function because it depends on what path the person takes (the climber could have taken a shortcut or a longer, more scenic route). The change...
by Nickolas Manipud 1C
Sat Dec 09, 2017 8:12 pm
Forum: Naming
Topic: Test 4
Replies: 4
Views: 365

Re: Test 4

Rachel Formaker 1C wrote:Diaquadifluoromercury(I)


Wouldn't mercury have a charge of 3+ and not 1+?
by Nickolas Manipud 1C
Sat Dec 09, 2017 8:05 pm
Forum: Naming
Topic: Test 4
Replies: 4
Views: 365

Test 4

What's the name for [HgF2(OH2)2]+ ?
by Nickolas Manipud 1C
Thu Nov 30, 2017 5:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ch 11 #89
Replies: 2
Views: 163

Re: Ch 11 #89

Clarisse Wikstrom 1F wrote:What do you mean by "ratios of the change in equilibrium"?


When you draw the ICE box, in the "Change" row, you would get 10, 5, and 10 for A, B, and C, respectively. The ratios of 10, 5, and 10 are 2:1:2 which tells you the number of moles for A:B:C.
by Nickolas Manipud 1C
Thu Nov 30, 2017 1:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ch 11 #89
Replies: 2
Views: 163

Ch 11 #89

The following plot shows how the partial pressures of reactant and products vary with time for the decomposition of compound A into compounds B and C. All three compounds are gases. Use this plot to do the following: (a) Write a balanced chemical equation for the reaction. (b) Calculate the equilibr...
by Nickolas Manipud 1C
Thu Nov 30, 2017 1:29 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Ch 11 #87c
Replies: 1
Views: 128

Ch 11 #87c

Dissociation of a diatomic molecule, X2(g) -> 2 X(g) occurs at 500 K. Picture 1 shows the equilibrium state of the dissociation and picture 2 shows the equilibrium state in the same container after a change has occurred. Which of the following changes will produce the change shown? (c) Decreasing th...
by Nickolas Manipud 1C
Tue Nov 28, 2017 1:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ch 11 #47
Replies: 1
Views: 286

Ch 11 #47

For the reaction pcl5 \rightleftharpoons pcl3 + cl2 , Kc = 1.1 x 10^-2 at 400 K. (a) Given that 1.0 g of PCl5 is placed in a 250.-mL reaction vessel, determine the molar concentrations in the mixture at equilibrium. (b) What percentage of the PCl5 has decomposed at equilibrium at 400. K? I tried usi...
by Nickolas Manipud 1C
Tue Nov 21, 2017 12:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework Question 11.7 [ENDORSED]
Replies: 4
Views: 246

Re: Homework Question 11.7 [ENDORSED]

clararehmann1B wrote:Notice that you can see which molecules have decayed within the flask. Start with counting out how many molecules have split apart!


The answer is flask 3 but I counted the the number of molecules that have split apart and there are 12 of these in both flasks 3 and 4. So why is flask 3 the answer?
by Nickolas Manipud 1C
Sun Nov 19, 2017 4:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 4
Views: 216

Bond Angles

Do we have to know any other specific bond angles beside 90, 120, 180, and 109.5? For example, should we know that a trigonal pyramidal molecule has bond angles of 107 degrees or just that it is less than 109.5?
by Nickolas Manipud 1C
Sat Nov 18, 2017 1:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: trigonal planar vs. t-shaped
Replies: 5
Views: 602

Re: trigonal planar vs. t-shaped

Emma Li 3F wrote:How do you tell if a molecule (with 4 atoms) has a trigonal planar shape or is t-shaped?


I was having trouble with this too but this picture really helps
https://goo.gl/images/2yK9vp
by Nickolas Manipud 1C
Fri Nov 17, 2017 2:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm on myucla
Replies: 6
Views: 376

Re: Midterm on myucla

Essly Mendoza 1J wrote:Do you guys know what the average on the midterm was? Thanks!


Lavelle said 83%
by Nickolas Manipud 1C
Fri Nov 17, 2017 12:54 am
Forum: Hybridization
Topic: Hybridization in Carbon
Replies: 3
Views: 142

Re: Hybridization in Carbon

Remember you're only counting the REGIONS of electron density so single, double, and triple bonds are all considered as one region of electron density
by Nickolas Manipud 1C
Fri Nov 17, 2017 12:44 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm on myucla
Replies: 6
Views: 376

Re: Midterm on myucla

Mine is up but I wouldn't worry about it. It should be up eventually
by Nickolas Manipud 1C
Thu Nov 09, 2017 12:16 pm
Forum: Quantum Numbers and The H-Atom
Topic: Maximum electrons
Replies: 2
Views: 188

Re: Maximum electrons

You would count the total number of electrons in the s-, p-, d-, and f- subshells which is 32 electrons. Then, since the question is only asking for electrons with ms = +1/2, you would divide 32 in half to get your answer of 16 electrons.
by Nickolas Manipud 1C
Thu Nov 09, 2017 12:11 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Relationship between Orbitals and Properties of Electrons
Replies: 2
Views: 142

Re: Relationship between Orbitals and Properties of Electrons

I know that elements in s- and d-orbitals can become cations so therefore, their electrons tend to be given away. Meanwhile, in p-orbitals, the elements can become anions so they want to keep their electrons and pull in more electrons from a cation to create a stable valence shell.
by Nickolas Manipud 1C
Thu Nov 02, 2017 4:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Quantum Numbers
Replies: 3
Views: 143

Re: Quantum Numbers

Remember that l = (n-1) so if n=7, then the possible l values are 0,1,2,3,4,5,6
by Nickolas Manipud 1C
Wed Nov 01, 2017 3:20 pm
Forum: Trends in The Periodic Table
Topic: 2.67
Replies: 5
Views: 281

Re: 2.67

Can anyone explain to me why Cl has a higher electron affinity than Br? In general, electron affinity decreases as you go down a group because there are more shells between the nucleus and the valence electrons. As a result, the nuclear charge has less of an effect in pulling the valence electrons ...
by Nickolas Manipud 1C
Tue Oct 31, 2017 11:33 am
Forum: Trends in The Periodic Table
Topic: Chapter 2, Question 85
Replies: 1
Views: 181

Chapter 2, Question 85

Question: In the heavier transition-metal elements, especially the lanthanoids and actinoids, there are numerous exceptions to the regular order of orbital occupation predicted by the buildingup principle. Suggest why more exceptions would be noted for these elements. Answer from Solutions Manual: ...
by Nickolas Manipud 1C
Tue Oct 31, 2017 11:11 am
Forum: Trends in The Periodic Table
Topic: Electron affinity of Carbon vs Nitrogen
Replies: 1
Views: 146

Electron affinity of Carbon vs Nitrogen

Why does carbon have a higher electron affinity than nitrogen when the general trend is that electron affinity increases to the right?
by Nickolas Manipud 1C
Sat Oct 21, 2017 1:46 pm
Forum: Quantum Numbers and The H-Atom
Topic: Radial Nodes [ENDORSED]
Replies: 1
Views: 127

Radial Nodes [ENDORSED]

What is a radial node and how would you determine the number of radial nodes for orbitals?
by Nickolas Manipud 1C
Thu Oct 19, 2017 11:50 am
Forum: Properties of Light
Topic: EM spectrum
Replies: 6
Views: 398

Re: EM spectrum

You should know that visible light is about 400-700 nm.

It also may be useful to know the order of the EM spectrum and that the Balmer series consists of visible light and Lyman consists of UV.
by Nickolas Manipud 1C
Sun Oct 15, 2017 6:42 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Post Module #37
Replies: 1
Views: 140

Atomic Spectra Post Module #37

Write the equation that allows one to calculate the electronic energy levels for the hydrogen atom. Do the calculated energies compare favorably with empirical observation (spectroscopic results)?

What does the second part mean?
by Nickolas Manipud 1C
Sat Oct 14, 2017 11:07 am
Forum: Photoelectric Effect
Topic: Constants that need to be memorized
Replies: 6
Views: 317

Re: Constants that need to be memorized

On Lavelle's website, you'll find a link that says "Constants and Equations." I feel like the ones in there will be given on the test.
by Nickolas Manipud 1C
Sat Oct 14, 2017 11:03 am
Forum: Photoelectric Effect
Topic: Photon vs. Energy [ENDORSED]
Replies: 6
Views: 300

Re: Photon vs. Energy [ENDORSED]

They're not really interchangeable terms.

I like to think of photons as "packets" of light. Photons carry an energy that determines how fast they move. This is important because the photon's speed (aka their frequency) can help us find that photon's wavelength and energy.
by Nickolas Manipud 1C
Sat Oct 14, 2017 10:54 am
Forum: Properties of Electrons
Topic: Energy Level Change
Replies: 5
Views: 304

Re: Energy Level Change

It is possible for the electron to continue to move to higher levels. More often than not, the electron will drop back down to the ground state because it is most stable there. However, if an electron jumps to the first state, it can jump to the second state if the electron absorbs another photon ju...
by Nickolas Manipud 1C
Thu Oct 05, 2017 8:43 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E7 [ENDORSED]
Replies: 9
Views: 517

Re: E7 [ENDORSED]

I don't round my sig figs until the very end to prevent my answer from going too far off from the correct answer.
by Nickolas Manipud 1C
Thu Oct 05, 2017 4:29 pm
Forum: Molarity, Solutions, Dilutions
Topic: E9 [ENDORSED]
Replies: 5
Views: 1358

Re: E9 [ENDORSED]

You multiply it by 11 O atoms because that is how many O atoms are in magnesium sulfate heptahydrate (MgSO4 * 7H20)

Multiplying it by 11 will give you moles of O which you then multiply by Avagadro's constant (6.022 * 10^23) to get the number of O atoms.

Hope this helped!

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